WORKING PAPER 2015–3

Testing methods for heavy-duty vehicle fuel

efficiency: Trends from regulatory programs
around the world and implications for India
Author: Ben Sharpe
Date: 20 April 2015
Keywords: Heavy-duty vehicle fuel economy standards, vehicle testing and certification, regulatory design

1. Introduction that are employed or are under consideration in each of

these programs. The subsequent section discusses the
In response to the growing contribution of the trucking
opportunities and challenges facing India, specifically
sector to global warming and local air quality impacts,
in terms of the test procedure options in play as policy-
many nations and regions around the world have
makers design a HDV fuel efficiency regulation. In the
developed programs and policies to improve the envi-
final section, we outline concrete recommendations for
ronmental performance of heavy-duty vehicle fleets. To
test procedure development/adoption in India as well
date, Japan, the U.S., Canada, and China have enacted
as timelines for implementation. Moreover, we highlight
mandatory fuel efficiency or greenhouse gas (GHG)
future research that can build on this test procedure
standards for new heavy-duty vehicles (HDVs), and
assessment and also preview the additional analysis
many other countries are in various stages of develop-
planned by the ICCT that will support fuel efficiency
ment for their own regulatory measures.
regulatory development for HDVs in India.
The primary objectives of this paper are to explore
This working paper is the first in a series of papers
methods for testing and certifying the fuel efficiency
that the ICCT will be releasing that touch on various
of HDVs and vehicle components in the established
aspects related to regulatory development for HDV
and emerging regulatory programs around the world
efficiency in India. These analyses will include a market
and the implications for India, as policymakers there
study, industry survey, and a comprehensive technology
deliberate establishing a performance standard of their
potential report.
own. In the India context, one of the key open regulatory
design questions is whether a program centered around
full vehicle certification or individual engine testing 2. Overview of current and developing
is most appropriate as a first phase regulation. The fuel efficiency regulations for HDVs
primary contribution of this paper is to provide an
analysis of the advantages and disadvantages of each Since 2006, Japan, United States (U.S.), Canada, China,
of these options and present the ICCT’s recommended and California have adopted some form of fuel efficiency
path forward for India. or GHG standard for heavy-duty commercial trucks
and buses, while India, Brazil, Mexico, South Korea,
This paper begins by briefly summarizing the various fuel and the European Union (E.U.) are in the process of
efficiency and GHG regulations that have been estab- developing such regulations. Combined, these nine
lished or are in the process of being developed in Japan, regions represent more than three quarters of global
the U.S., Canada, and China as well as the HDV CO2 certi- heavy-duty vehicle (HDV) fuel consumption, as shown
fication approach that is being initiated in the European in Figure 1 (Facanha, Miller et al. 2014). The ICCT’s best
Union. These brief regulatory summaries are followed by judgment as to the regulatory development timelines in
more details about the testing and certification methods each of these countries and regions is shown in Table 2.

Acknowledgements: This work was funded by the Shakti Sustainable Energy Foundation. The author thanks Anup Bandivadekar, Oscar Delgado, and
Fanta Kamakaté for their critical reviews.

© INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION, 2015 WWW.THEICCT.ORG

TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Heavy-duty freight vehicle fuel use

(million BOE/day)
HDV efficiency Regulations under
regulation in place consideration 0.0 1.0 2.0 3.0
U.S. P P
China P P
EU-27 P
India P
Japan P P
Brazil P
Russia
Canada P P HHDV (14k + kg)
Mexico P MHDV (6.4 - 14k kg)
S. Korea P LHDV (3.5 - 6.4k kg)

Figure 1: Nations with active or emerging regulatory programs for heavy-duty vehicles
(BOE = barrels of oil equivalent)

Because of the complexities of the HDV sector, designing a important exceptions are Japan and South Korea, where
regulatory program for HDVs presents unique challenges. medium-duty trucks and buses dominate heavy-duty
For example, measuring the fuel efficiency of a HDV vehicle fuel use.
can be quite complicated since a single engine model
can be paired with a large number of chassis types and In the remainder of this section, brief program overviews
transmissions, with each combination having different are presented for each of the jurisdictions that have
fuel consumption characteristics. Furthermore, the fuel implemented fuel efficiency regulations for HDVs. Though
efficiency of a given vehicle in use may vary dramati- the E.U. has not put a mandatory performance standard
cally based upon the duty cycle. Another attribute of in place for commercial vehicles, we provide a summary
the heavy-duty industry that presents challenges from a of their approach for testing and certifying the fuel con-
regulatory perspective is the fact that vehicle manufactur- sumption and CO2 emissions from HDVs.
ing is often a fragmented and highly customized process.
Unlike passenger cars and light-duty trucks, the assembly
2.1 JAPAN
of HDVs can involve multiple different manufacturers,
suppliers, and upfitters. For example, for a particular city Japan deserves credit as the world’s first country to
delivery truck, one component manufacturer might make establish HDV fuel economy standards in 2006 as part of
the engine; another company might supply the transmis- the country’s commitment to the Kyoto Protocol (Ministry
sion; a separate manufacturer could be responsible for of Economy Trade and Industry (METI) and Ministry of
incorporating the engine and transmission and building the Land Infrastructure Transport and Tourism (MLIT) 2005).
rolling chassis; and, finally, an upfitter would be responsible Separate fuel economy standards were established for
for assembling the body that encapsulates the chassis and city buses and for heavy-duty trucks, and there are unique
carries the cargo. Given that vehicle design and manu- stringency requirements that vary by vehicle mass. Truck
facturing are often shared among multiple entities whose weight classes ranged from 3.5 to 20 metric tons, while
individual contributions can all have unique impacts on buses ranged from less than 8 to greater than 14 metric
the ultimate fuel efficiency performance of a vehicle, this tons. On average, the standards required an improvement
can potentially present challenges in terms of identifying a in fuel economy of 12% by 2015, or a 1.2% annual improve-
single regulated entity. ment. These standards were incorporated into Japan’s
broad Top Runner system for energy efficiency, where
The HDV market is so complex and varied that the the current best performer efficiency is used to set future
U.S., Canada, and China have focused the bulk of their standards. Each manufacturer is required to meet the fuel
regulatory attention on the most energy intensive economy target in each bin it sells vehicles, based upon
vehicle types. In these three nations, long-haul tractor- a sales-weighted average for that bin, with no opportuni-
trailers are the top energy consumers. Indeed, as shown ties for cross-bin crediting (The International Council on
in Fig. 1, the heaviest class of commercial vehicles, which Clean Transportation (ICCT) 2008).
includes long-haul tractor-trailers, account for the bulk
of fuel consumption for seven out of the nine nations After considering several testing options based upon
currently considering fuel economy standards. The two multiple criteria — equipment and labor costs, accuracy,

2 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION  WORKING PAPER 2015-3

 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

the ability to account for non-engine efficiency improve- their respective authorities. The EPA developed GHG
ments, and overlaps with emissions test cycles — the emission standards under the Clean Air Act, and the
Japanese government chose to measure fuel economy NHTSA developed fuel consumption standards under
under its heavy-duty standards through a combination the 2007 Energy Independence and Security Act.
of engine-only fuel consumption testing and simulation Environment Canada’s authority covers GHG emissions,
modeling of gear shifting and vehicle resistance loads. so its standards are linked to the EPA’s GHG regulation.
The test method as designed essentially constrains The fuel efficiency and GHG standards are designed
compliance options for manufacturers to engine to be functionally equivalent, based on carbon dioxide
efficiency improvements only. Since the simulation model (CO2) conversion factors for each fuel. In addition, the
assigns standard values by fuel efficiency category for EPA standard also includes limits on engine nitrous oxide
driving resistance and chassis size, efficiency improve- (N2O) and methane (CH4), as well as limits on emissions of
ments due to changes in these variables are not counted refrigerant from air-conditioning systems.
toward compliance.
The U.S. approach mirrors the Japanese program by
Japan’s focus on engine efficiency improvements in adopting a simulation modeling strategy, but the U.S.
its regulation aligns well with the technology potential program is distinct in two important ways. First, the U.S.
that exists at lower driving speeds. At lower speeds that program sets an engine standard that is separate and
are typical of urban driving, losses in the engine and unconnected from the vehicle standard. The second major
transmission tend to dominate, while as speed increases, contribution from the U.S. rule proposal is the expansion
aerodynamic and rolling resistance drag represent of the simulation modeling approach to include additional
an increasing share of overall energy consumption elements of potential efficiency gains from tires, aerody-
(Delorme, Karbowski et al. 2009). Given that urban namics, weight reduction, and other factors as discussed
driving accounts for a large percentage of overall HDV below. As with Japan’s fuel economy rule, compliance with
fuel consumption in Japan, the regulation’s emphasis on the U.S. regulation is based on sales-weighted averaging.
engine improvements is a logical point of focus for its Thus each manufacturer’s product mix must meet the
first phase regulation. targets, on average, based on sales-weighting of vehicles
that generate credits (i.e., vehicles that perform better
For the next iteration of its heavy-duty standards, Japan’s than the target) and debits (i.e., vehicles that consume
regulatory agencies are researching how to update their more fuel/emit more CO2 than the target).
testing and simulation methods as well as how best to
incorporate a wider range of technology improvements The U.S. rule can be thought of as four rules combined
beyond just the engine (e.g., aerodynamics, reduced tire into one regulation. There are distinct provisions for the
rolling resistance, light-weighting, advanced transmis- four primary regulatory subcategories: tractor trucks,
sions, and hybrid powertrains). pickup trucks and vans, vocational vehicles, and engines
of tractor trucks and vocational vehicles.
2.2 UNITED STATES AND CANADA Tractor trucks account for the largest percentage of
Five years after Japan’s policy action, the U.S. finalized fuel consumption and GHG emissions from the HDV
fuel efficiency and GHG emission standards for medium- sector and thus attract the greatest amount of regulatory
and HDVs in the fall of 2011 (The International Council attention in the rule. There are nine separate standards for
on Clean Transportation (ICCT) 2011, U.S. Environmental tractor trucks based on combinations of three categories
Protection Agency 2011). Canada followed roughly a year- of vehicles (Class 7, Class 8 day cab, and Class 8 sleeper
and-a-half later with its own rule, which was published cab) and three roof height categories (low, medium, and
in the spring of 2013 and is largely identical to the high). Regulatory stringency ranges from 9% to 23% for
U.S. regulation (Environment Canada 2013). The U.S. model year (MY) 2017 vehicles compared with the MY
Environmental Protection Agency (EPA) and the National 2010 baseline. Table 1 presents a high-level summary of
Highway Traffic Safety Administration (NHTSA) worked the tractor standards as well as the primary elements of
collaboratively to deliver these Phase 1 regulations under the other three major regulatory categories.

WORKING PAPER 2015-3 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION 3

TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Table 1: Major elements of the U.S. and Canada heavy-duty vehicle regulations

Stringency versus
Regulatory Category Regulatory Subcategories Compliance Assessment MY 2010 Baseline
Greenhouse Gas Emissions Model
(GEM) simulation
Nine subcategories based on weight,
Tractor trucks Inputs: aerodynamics, tire rolling 9% to 23%
cab configuration, and roof height
resistance, weight reduction, idle
reduction, vehicle speed limiter
Heavy-duty pickup trucks • Diesel 12% for gasoline
Chassis dynamometer testing
and vans • Gasoline 17% for diesel
• Light heavy-duty (Classes 2B-5)
• Medium heavy-duty GEM simulation
Vocational vehicles 6% to 9%
(Classes 6 and 7) Inputs: tire rolling resistance
• Heavy heavy-duty (Class 8)
• Light heavy-duty (Classes 2B-5)
• Medium heavy-duty
Engines for tractors and (Classes 6 and 7)
Engine dynamometer testing 5% to 9%
vocational vehicles • Heavy heavy-duty (Class 8)
• Gasoline and spark-ignited engines
(all classes)

Tractor manufacturers must demonstrate compliance or heavy-duty pickup trucks or vans and includes a vast
with the tractor standards using the Greenhouse Gas array of different vehicle configurations (e.g., bucket
Emissions Model (GEM), a vehicle simulation program that trucks, refuse vehicles, and buses), duty cycles, and
was developed by the EPA and NHTSA. For tractors, inputs payloads. The regulated entity is the chassis manufac-
to the model include data on aerodynamics, tire rolling turer. Manufacturers comply with the vocational vehicles
resistance, weight reduction, extended idle reduction, standards using the GEM software by inputting tire rolling
and vehicle speed limiting. In addition, there is a separate resistance test data.
standard for engines of tractor trucks as discussed below.
Notably, transmissions are not included in the suite of The stringency of the vocational vehicle standards is
technologies that are part of the standard compliance premised solely on improvements in engines (driven by
pathway using the GEM program. In the regulation, the the separate engine standard) and tires rolling resistance
EPA and NHTSA explain that transmissions (and axle and does not incorporate savings opportunities from
ratios) were not included in the core set of compliance other areas such as aerodynamics, transmissions and
technologies for tractors and vocational vehicles for two hybrids, and weight reduction. This is not because the
primary reasons: (1) lack of baseline data and (2) the desire agencies have rejected the technology potential across
to avoid unintended disruptions to the market. many vocational applications, but rather that there are
obstacles to capturing these savings given the structure
Heavy-duty pickup trucks and vans with a gross vehicle and protocols of the regulation. For example, the aero-
weight (GVW) between 8,500 and 14,000 pounds are dynamic coefficient of drag is not an input parameter
often very similar to their counterparts in the light-duty in the vocational vehicle module in GEM, since a single
category. Because of the similarities among light- and chassis may be used with multiple bodies that have vastly
heavy-duty pickups and vans, the testing and compliance different aerodynamic profiles.
approach is closely related to the program for LDVs. The
Class 2B and 3 vehicles are tested on a chassis dynamom- Engine testing for compliance with fuel consumption and
eter with the stringency of the standards scaled by a newly GHG standards is designed to occur simultaneously with
created “work factor” that reflects the vehicle’s utility (i.e., testing for criteria pollutants using the same procedures
hauling capacity, payload, and capacity for four-wheel and test cycles that are currently used. In effect, three
drive). There are separate standards for diesel and gasoline more pollutants must be measured and reported: CO2,
vehicles, and, in MY 2018, the average CO2 emissions CH4, and N2O. The procedures to determine which engines
compared with a MY 2010 baseline must be 12% lower for must actually be tested will also remain the same as in
gasoline vehicles and 17% lower for diesel vehicles. current criteria pollutant testing. Engines are categorized
as light-heavy (Class 2B through 5), medium-heavy (Class
The vocational vehicle category is a catchall group for the 6 and 7), and heavy-heavy (Class 8) based on what
rest of the HDVs that are not classified as tractor trucks vehicle class they are ultimately used in.

4 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION  WORKING PAPER 2015-3

 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

2.3 CHINA developing a simulation-based methodology for testing

and certifying the CO2 emissions of HDVs. The backbone
Tractor-trailers, dump trucks, and straight trucks account
of the European certification process is the Vehicle
for nearly two-thirds of fuel consumption in the HDV
Energy Consumption calculation Tool (VECTO). VECTO
sector in China, and thus represent the categories of
is currently in the proof-of-concept phase and is still
HDVs worthy of the initial regulatory focus (Zheng 2013).
being validated before it becomes the official software
The composition of the Chinese market is substantially
that manufacturers must use to evaluate each vehicle
different than that of U.S. and European markets, where
model’s CO2 emissions and fuel efficiency. As with Japan’s
tractor-trailers account for greater than half of fuel con-
model and the GEM tool in the U.S. and Canada, VECTO
sumption in the sector. In China, single-unit trucks (e.g.,
uses component test data from physical testing (e.g.,
straight trucks, dump trucks) account for the greatest
track testing for determining aerodynamic drag, engine
share of fuel consumption (ibid).
mapping based on dynamometer results, etc.) to create
The first phase “Industry Standard” was issued in 2011 a virtual representation of the vehicle that can then be
for implementation in mid-2012 for new models, and exercised over mission-specific drive cycles (Fontaras,
mid-2014 for all vehicles. Under the Industry Standard, Rexeis et al. 2013). The key aspect in which the European
three HDVs categories are regulated—straight trucks approach differs from that in North America is that there
(not including dump trucks), coach buses (not including is no separate engine standard to go along with the
city buses), and tractor trucks. The currently adopted, VECTO certification process.
second phase “National Standard” went into effect for
The policy outcome for the E.U. has not yet been decided.
new HDV models in mid-2014. This regulation tightened
Two options are currently under consideration. A labeling
the stringency of standards by an average of 10.5% to
and information program would provide consumers and
14.5% compared to the limits under the Industry Standard.
HDV purchasers with accurate, detailed information about
Besides the aforementioned three types of HDVs the
fuel efficiency across multiple configurations and manu-
standards added in two new categories of vehicles—city
facturers. A central question for European policymakers
buses and dump trucks (Muncrief 2013).
is whether enhanced consumer information through a
For their certification approach, China has implemented a labeling and information program will suffice to capture the
framework in which “base” vehicles must be evaluated on technological potential for European HDVs. Alternatively,
a chassis dynamometer, but manufacturers have the ability the Commission could develop mandatory performance
to use an official simulation model to certify “variants” of targets for CO2 /ton-km. These two policy options are not
the base vehicle models. China’s primary reliance on chassis mutually exclusive, but are actually quite complementary.
testing to determine compliance is particularly noteworthy
given that all other nations that have adopted or are con- 2.5 CALIFORNIA
sidering HDV efficiency standards have designed their test
procedure process to feature simulation modeling as the As part of the regulatory mandate to reduce GHG
primary means of certification. emissions from all sectors of the California economy,
the California Air Resources Board (ARB) developed a
regulation that aims to increase the efficiency of tractor-
2.4 EUROPEAN UNION trailers operating in California. This regulation, which
The European Commission has been working closely with was first proposed in late 2008 and formally finalized in
its domestic HDV industry since the summer of 2007 early 2012 (California Air Resources Board (CARB) 2012),
to develop a new program focused on controlling fuel has mandatory equipment specification provisions for
consumption and CO2 emissions from HDVs. The collabo- trucking fleets that affect both tractors and trailers. The
ration has primarily focused on assessing the technical reduction in fuel use and GHG emissions will be achieved
potential of mitigation options for HDVs, developing a by requiring the use of aerodynamic tractors and trailers
simulation modeling tool, and a set of mission-based test that are also equipped with low rolling resistance tires.
cycles and procedures for each major class or category The tractors and trailers subject to this regulation must
of HDV. either use U.S. EPA SmartWay certified tractors and
trailers or be retrofitted with SmartWay verified tech-
For the past few years, much of the attention from nologies. California’s program is the first in-use GHG
regulators and industry in Europe has been around regulation in the world.

WORKING PAPER 2015-3 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION 5

 Table 2: Regulatory development timelines for heavy-duty vehicle efficiency and GHG regulations around the world

Regulation
Type 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Phase 1 regulation implemented starting MY 2015  

Fuel
Japan
economy
Phase 2 under
Phase 2 implementation
consideration

Standard   Regulation implemented starting MY 2014

Final rule  
proposal   (mandatory DOT program starts MY 2016)
United GHG/Fuel
States efficiency
  Phase 2 regulatory Phase 2 Phase 2  
  Phase 2 implementation
  development proposal  final rule   

  Standard Regulation implemented starting MY 2014

Final rule
  proposal (optional until MY 2016)
Canada GHG
Phase 2 regulatory Phase 2 Phase 2
Phase 2 implementation
development proposal final rule

6 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION 

Test Industry Industry National
Fuel Final regulation of National standard effective on July 1, 2014 for newly certified Next phase
China procedure standard standard standard
consumption vehicles and July 1, 2015 for existing vehicles implementation
finalized proposal implemented adopted

European CO2 test Impact Test protocol and simulation

Technical studies   Policy implementation
Union procedure assessment model finalization 

Impact assessment
Fuel Regulatory development and
Korea Technical studies and test procedure
efficiency finalization
development

End-user
Requirements for new Additional requirements for existing tractors Additional requirements for existing trailers and reefers (< MY
California purchase  
tractors, trailers (2011+) and trailers (< MY 2010) 2010)
requirements

(Text in orange represents the ICCT’s best estimate as to the timing of these regulatory developments)
TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

WORKING PAPER 2015-3

 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

3. Testing and certification pathways emissions and fuel economy tests of heavy-duty
vehicles on chassis dynamometers (SAE J2711) (Society
Heavy-duty vehicles are produced in a much greater of Automotive Engineers (SAE) 2002), and the EPA has
range of sizes and configurations than light-duty detailed procedures for conducting emissions testing
vehicles, and have a more diverse range of in-use duty (40 CFR Part 86 (U.S. Environmental Protection Agency
cycles. Also, chassis dynamometers and the associated (EPA) 2015), 40 CFR Part 1065 (U.S. Environmental
facilities that can accommodate the significant loads Protection Agency (EPA) 2015)).
and test apparatus of heavy-duty vehicles are often
expensive and much less common than light-duty The most significant benefit of this test method is that
chassis dynamometers. As such, governments and it effectively brings the entire drivetrain into the test.
industry have historically opted for work-specific As such, it can be used to provide a realistic assessment
engine-based standards and engine dynamometer of distance-specific emissions and fuel use for a wide
testing for criteria pollutant emissions certification. range of advanced vehicle and drivetrain technologies,
However, because traditional engine dynamometer including all hybrid configurations.
testing may not be fully adequate for properly repre-
Compared to engine testing, chassis dynamometer
senting vehicle operations, governments and industry
testing is time consuming and expensive. In this method
have been formulating different strategies for certifying
the vehicle is stationary during the test, and the aero-
CO 2 emissions and fuel consumption performance.
dynamic load is not imposed on the vehicle surface as it
These options include certification pathways based on
is during driving. Instead, a simulated aerodynamic load
the following testing methods:
is imposed on the vehicle through the tires by adjusting
• Chassis dynamometer the load on the dynamometer rolls. In effect, the dyna-
• Engine dynamometer mometer uses inertial and electrically generated loads
applied through the vehicle’s tires to simulate aerody-
• Powertrain dynamometer
namic load.
• Simulation modeling
The required load is determined by conducting an
• Closed test track
on-road coastdown test prior to the dynamometer
All of these options are described further below. testing. In a coastdown test the vehicle is accelerated to
Following the test procedure descriptions below, some speed and then allowed to coast to a stop without
Section 3.2 presents a comparison of these options applying the brakes, while vehicle speed versus time is
according to a number of criteria as well as how the recorded. By calculating the varying deceleration rate of
regulatory programs discussed in Section 2 differ in the vehicle over time, one can compute the forces (rolling
terms of testing and certification strategies. resistance and aerodynamic drag) that were operating on
it at each speed. This information is programmed into
the dynamometer so that it will impose the appropri-
3.1 METHODS OF TESTING AND CERTIFYING ate load on the vehicle at each point in the test cycle.
HEAVY-DUTY VEHICLES The vehicle is then mounted on the dynamometer,
and a dynamometer coastdown test is conducted to
3.1.1 Full vehicle chassis dynamometer testing ensure that the coastdown profile is the same on the
In this test method, the full vehicle is mounted on a dynamometer as it was on the road. An alternative to
dynamometer with the drive wheels resting on one or performing coastdowns is constant speed testing. As
more large cylindrical rolls. The vehicle is stationary the name suggests, constant speed tests derive the
during testing, but the drive wheels spin the rolls to total driving resistance by evaluating the vehicle during
simulate driving at different speeds1. The dynamometer steady-state operation on a test track.
imparts varying loads to the drive wheels to represent
varying vehicle inertial load, rolling resistance, and While this method of evaluating and simulating rolling
aerodynamic drag throughout the drive cycle. The resistance and aerodynamic drag on a dynamometer
vehicle driver follows a specific profile of speed versus is theoretically sound, it is critical that the coastdown
time, and is usually given a computerized driver’s aid, (or constant speed) test be conducted correctly. The
which shows actual speed versus target speed in real accuracy of chassis dynamometer testing is limited by
time. The Society of Automotive Engineers (SAE) has the accuracy of the coastdown data used to calibrate
developed a recommended practice for conducting the dynamometer for a specific vehicle. The largest
constraint on coastdown testing is finding an appropri-
1 To avoid tire slippage during high torque operations, some heavy-duty ate location to conduct the test (a straight and level
chassis dynamometers are designed such that the load-transmitting road of sufficient length where the air is relatively still).
axle is directly connected to the wheel hubcap.

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

The accuracy and repeatability of coastdown tests are certification testing. For many years, governments and
significantly affected by test track configuration and industry have been accustomed to using engine test
ambient conditions. cycles such as the U.S. Federal Test Procedure (FTP)
transient cycle and the European Transient Cycle (ETC)
There are several standardized HDV cycles in existence; for criteria pollutant certification purposes. Moreover,
TransportPolicy.net is an extensive online reference. There another advantageous aspect of this test method is
are cycles specific to a number of different types of HDV the relatively high test-to-test repeatability of the mea-
driving patterns, including cycles tailored to tractor- surements compared to chassis dynamometer results.
trailers, delivery trucks, transit buses, coach buses, and Unlike the chassis dynamometer procedure, there is
refuse vehicles. All of these cycles have vehicle speed no tire slip, no error introduced by human drivers,
versus time (in seconds), and the vehicle operator (i.e., and most temperatures and pressures can be tightly
the person operating the vehicle on the chassis dyna- controlled in a laboratory setting (e.g., air, fuel, engine
mometer) must following the speed trace as closely as coolant, oil, etc.).
possible. In addition to chassis dynamometer testing,
vehicle cycles are also used in simulations models to A key drawback of using engine testing for HDV fuel
evaluate vehicle performance. efficiency testing is that existing cycles are arguably
not reasonably representative of how modern engines
From a regulatory perspective, China is the only juris- operate under real-world conditions. Certain stakehold-
diction that requires chassis dynamometer testing. The ers, including vertically integrated original equipment
cycle used for evaluating all HDVs in China (on both manufacturers (OEMs), contend that optimizing engine
the chassis dynamometer for “base” vehicles and in performance to engine cycles leads to sub-optimal fuel
the simulation model for “variant” vehicles) is a slightly efficiency during actual operations (Daimler Trucks
modified version of the World Harmonized Vehicle North America 2014, Volvo Group 2014).
Cycle (WHVC), the C-WTVC. As shown in Figure A1,
the C-WTVC is very similar to the WHVC. Some of the All of the countries with criteria pollutant regulations
original WHVC acceleration and deceleration values have utilized standardized engine cycles for testing and
are reduced in order to reflect Chinese HDVs, which, certification for many years. The introduction of the U.S.
on average, have lower engine power-to-vehicle weight and Canada’s Phase 1 GHG regulations represent the
ratios than HDVs from other major markets (i.e., Europe, first time that these engine cycles have been used for
North America, and Japan) that were used to develop testing fuel consumption and CO 2 emissions. Some of
the WHVC. the key advantages and disadvantages of using engine
cycles that were originally derived to test criteria
Both the WHVC and C-WTVC are comprised of three mini- pollutants to evaluate an engine’s fuel consumption
cycles: an urban, interurban, and highway driving portion. performance are discussed below in Section 4.1.
In China’s regulation, the fuel efficiency for each of these
three mini-cycles is weighted according to the type of 3.1.3 Powertrain dynamometer testing
HDV, and the final certification value for each vehicle
A powertrain dynamometer test differs from a traditional
model is based on the weighted score. The weighting
engine dynamometer test in that it requires a dynamom-
factors for each of the regulatory subcategories are
eter that can accommodate the additional rotational
listed in Table A2, which summarizes all of the engine
inertia and torques associated with the inclusion of
and vehicle test cycles that are utilized in the regulatory
the transmission in the test setup. In practical terms, a
programs in Japan, the U.S. and Canada, and China.
powertrain test cell needs to have the power absorption
capabilities of a traditional heavy-duty chassis dyna-
3.1.2 Engine dynamometer testing
mometer, but with the power absorbers connected
Existing engine certification test cycles are designed directly to the transmission output shaft, rather than to
to offer a reasonable approximation of how an engine rollers that support the drive wheels of the test vehicle.
installed in a conventional vehicle would operate during
in-use driving. In this testing approach, the engine There are typically two strategies for testing a
is exercised using a standard engine dynamometer, powertrain in a dynamometer test cell. In the first
in which power and torque are measured from the strategy, the physical engine and transmission are linked
crankshaft of the engine. to computer-simulated models of the remaining vehicle
systems. In this powertrain-in-the-loop simulation
One of the most attractive aspects of the engine (PILS), the powertrain is exercised using a vehicle
dynamometer test method is that it is consistent with duty cycle (i.e., vehicle speed versus time). In this PILS
existing criteria pollutant regulatory programs, which approach, the engine and transmission operate as if
currently use engine dynamometers for all emissions they were in an actual vehicle. This PILS method requires

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

inputs for all of the other non-powertrain components functioning of all major systems such as engines and
(vehicle weight, aerodynamic drag coefficient, tire transmissions. In a regulatory context, for a single
rolling resistance, etc.). The second strategy aims at simulation model it is practically impossible to exactly
generating speed and torque at the output shaft of the replicate all of the various control strategies for the
transmission that will cause the engine to mimic the individual manufacturers, since regulators do not have
same operation it would experience during a specific access to CBI data.
engine certification duty cycle. In this setup, there is
no need for virtual vehicle parameters since there is Vehicle simulation has been an indispensible part
only physical hardware being tested. Since the speed of the vehicle design process for many years and is
and torque used in engine test cycles are not suitable now becoming an essential component of regulatory
programs as well. As discussed in more detail in Section
for powertrain testing (because they simulate torque-
3.2, simulation is an integral piece of all of the regulatory
speed characteristics at the engine output shaft), a test
certification procedures in existence today (including
cycle that simulates torque-speed characteristics at the
the E.U., which is developing an official simulation-
transmission output shaft is required for this strategy.
based certification process but has not indicated that
For more information about powertrain test cycles, see
a regulation will be pursued in the future). Vehicle
(Andreae and Sun 2012). Of the two methods described
simulation models can provide a relatively inexpensive
here, the PILS strategy generally does a much better
design platform and valuable source of timely informa-
job producing results closer to what would be experi-
tion, particularly in cases where physical testing and
enced under real-world vehicle operations.
experimenting becomes difficult.

3.1.4 Simulation model-based evaluation

3.1.5 Test track evaluation
Unlike chassis and engine dynamometer testing, the use
This test method involves operating the vehicle on
of simulation models for heavy-duty vehicle certification
a closed test course (typically a one mile or longer
is fairly new. Software models vary greatly in complexity
circular or oval track with banked corners). For each
and applicability, but, in general, a simulation model
test the driver is taught how to operate the vehicle for
uses actual data from physical systems to re-create a
the target test cycle. This includes parameters such as
virtual vehicle that can mimic, in computational space,
acceleration rates from each stop and target speeds
its real-world counterpart. Vehicle simulation software
between specific points on the track, braking rates and
can be used for the prediction of fuel consumption
stopping points, and idle times at each stop. The Truck
and CO2 emissions from HDVs under various operating
Maintenance Council (TMC) and SAE procedures for
conditions, as long as sufficiently detailed models are in-service and dynamometer tests can serve as the basis
provided and the necessary input data and parameters for a test track test protocol (Society of Automotive
are available. Engineers (SAE) 1986, Society of Automotive Engineers
(SAE) 1986, Society of Automotive Engineers (SAE)
The primary advantage of vehicle simulation tools is the
1987, Truck Maintenance Council (TMC) 1996).
ability to model a large number of vehicle variants and
subsystems using less time and resources than the other The most attractive aspect of this method is the fact
dynamometer-based methods. However, simulation that the complete physical vehicle is being tested on
programs do require physical testing (e.g., engine dyna- the road (albeit, in a controlled test track environment
mometer testing, coastdown testing, tire testing, etc.) without normal traffic conditions). In this sense, this
to create the data inputs that are the backbone of the is the most representative of all of the test methods.
modeling process. In general, the more representative However, the two major drawbacks are time and
(or “accurate”) a simulation model is of real-world resource intensity and poor test-to-test repeatability.
operations, the more time and resources are required
to validate the model and ensure its fidelity (see Figure
3). In addition, another challenge facing simulation 3.2 COMPARISON OF TEST METHODS
models is the increased complexity of modern engine, There are certain issues and challenges with each of the
powertrain, and vehicle control systems. For virtually all testing methods that are currently used to certify the
manufacturers and component suppliers, sophisticated fuel efficiency performance of HDVs. As shown in Table
control algorithms, which are considered confidential 3, none of the methods are clearly superior across all
business information (CBI), are integral to the proper the key regulatory parameters.

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Table 3: Advantages and disadvantages of the various methods for testing heavy-duty vehicles

Test Method Advantages Disadvantages

• Ability to test any vehicle configuration, including • Limited availability of chassis dynamometers due to
hybrids and vehicles with advanced transmissions high capital costs
• Ability to test all of the vehicle components as a • Testing is time and resource intensive
system
• Coastdown testing is a required prerequisite for
Chassis • Uses actual production control system algorithms developing road load inputs — limited availability
dynamometer during test of adequate test facilities, and variability based on
ambient conditions
• Not consistent with existing criteria pollutant
test procedures, which are based on engine
dynamometer testing
• Industry and regulators have strong familiarity with • Cannot test driveline systems such as the transmission
engine dynamometer testing — ability to leverage
• Existing engine cycles are arguably not
existing engine certification cycles
representative of how modern engines operate
Engine • Consistency with existing criteria pollutant under real-world conditions
dynamometer test procedures, which are based on engine
• May conflict with test procedures for fuel economy/
dynamometer testing
GHG emissions that are based on vehicle cycles. For
• Uses actual production control system algorithms example, there is currently no vehicle cycle that is
during test equivalent to the heavy-duty FTP engine cycle.
• Ability to test any vehicle configuration, including, • Very few powertrain test cells in existence
post-transmission parallel and series hybrids, and
• May conflict with existing criteria pollutant
Powertrain advanced transmissions. All driveline components
test procedures that are based on engine
dynamometer tested as a system.
dynamometer testing
• Uses actual production control system algorithms
during test
• Ability to evaluate a large number of vehicle variants • Increasing model sophistication and accuracy
in a timely and cost-effective manner requires added resources for physical testing and
model validation
Simulation • Minimizes time-consuming and expensive
dynamometer testing • Very challenging to accurately represent the
confidential control strategies of each manufacturer
• Perfect test-to-test repeatability
• Ability to test any vehicle configuration, including • Testing is time and resource intensive
post-transmission parallel and series hybrids, and
• Poor test-to-test repeatability
advanced transmissions
• Appropriate test protocols and data analysis
Test track • Ability to test all of the vehicle components as a
procedures would need to be developed if intended
system
for use in a regulatory context
• Uses actual production control system algorithms
during test

Because each of the testing options has strengths and

weaknesses in terms of cost, complexity, accuracy, and
transparency, it is understandable that different govern-
ments have developed unique approaches to testing and
certification pathways in their HDV regulations. However,
as shown in Figure 2, there is certainly a fair amount of
overlap in the test procedure approaches in each of the
regulatory programs.

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Payload Rolling resistance, aerodynamic drag Separate engine standard

~1/2 payload From Testing

Full Payload Standard Value

Chassis dyno testing

Simulation Model (base vehicles tested,

variants simulated)

Engine map Test cycles

From Testing 3 cycles (weighted)

Standard Value 2 cycles (weighted, incl. grade)

1 cycles (‘mini-cycles’ weighted)

Mission based (may incl. grade)

Figure 2: Test procedure comparison across the various HDV regulatory programs

From the figure, the most common element across all of the input of engine-specific data into the model a critical
the regulatory programs is simulation modeling. Though requirement to properly evaluate engine improvements.
the individual certification models in Japan, U.S./Canada,
China, and the E.U. are all unique, when we look at the Separate engine standards were a major point of
key input requirements and simulation conditions across contention between various stakeholders during the
the five jurisdictions, some important commonalities regulatory development of the Phase 1 rule, and this
emerge. Looking at engine data requirements, default debate continues on as the regulators in the U.S. and
engine maps are used in GEM (U.S./Canada), whereas Canada weigh options for the Phase 2 standards. Namely,
engine dynamometer-derived maps are needed for the the crucial decision is whether or not to maintain the
models in Japan, China, and the E.U. In their respective stand-alone program for engines. The advantages and
Phase 1 programs, both the U.S. and Canada elected to use disadvantages presented by separate engine standards
default engine maps in their certification process primarily are discussed more in Section 4 in the context of a
based on the fact that engines have their own separate potential HDV fuel efficiency regulation in India.
certification process. In other words, the North America
Another prominent question that policymakers in the
agencies were confident that the engine standards based
U.S. and Canada face is about how best to design the
on mandatory engine dynamometer testing would be
regulation to promote not only engine and road load
sufficient to drive engine technologies into the market
improvements, but also credit transmission improve-
and did not think that testing-derived engine data was a
ments within the core certification process. Transmission
necessary input to the GEM simulations. Therefore, Phase
advancements and the benefits of deeper engine-trans-
1 GEM is not designed to be as accurate as possible with
mission integration were not credited in the Phase 1 rule
respect to the powertrain (i.e., engine plus transmission).
within the primary testing and certification framework.
Furthermore, transmission and improved driveline tech-
As a result, the development of updated test procedures
nologies are not promoted within the standard GEM cer-
and certification methods that are more comprehensive
tification framework, and default values are used for these
in capturing powertrain technology efficiency benefits is
systems as well. In effect, since the GEM virtual vehicles
an issue of high importance to many stakeholders in the
all have default engines, transmissions, axle ratios, and tire
upcoming Phase 2 rulemaking.
radii, the function of GEM is explicitly limited to evaluating
road load-based technologies — namely, aerodynamics, Going back to Figure 2, aerodynamics and tire rolling
tire rolling resistance, weight and idle reduction, and speed resistance are key road load inputs in four out of five cer-
limiting. For the certification programs in Japan, China, tification pathways, with Japan being the only exception
and the E.U., the lack of a separate engine standard makes that uses default values for these parameters. Input

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

data for the aerodynamics of a vehicle is determined in the previous section, all of the simulation models
by coastdown testing (or constant speed testing in the require input data derived from physical component
European process) on a test track. For tires, the rolling testing (e.g., engines, aerodynamics, tires). However, what
resistance coefficient is determined by laboratory testing sets the European and Japanese approaches apart is that
in the U.S., Canada, and E.U., whereas, for the certifica- there are no separate dynamometer-based standards
tion process in China, the tire rolling resistance coef- that go along with the simulation requirement. The lower
ficient is determined using a formula (China Automotive right-hand corner of the figure represents a scheme solely
Technology and Research Center (CATARC) 2010, Zheng, dependent on physical chassis dynamometer testing. The
Jin et al. 2011). only country that requires chassis dynamometer testing
is China for “base” vehicles; however, “variants” may be
Some of the standardized test procedures that are most certified using the official simulation model.
commonly used for component testing input data for
aerodynamics, rolling resistance, and powertrains are If we look at the two options in the middle of the figure
listed in Table A1 in the appendix. — those which combine requirements for both simulation
and separate dynamometer testing as part of certification
process — we find the two regulatory programs in North
4. Test procedure challenges and America. Option (2) represents the Phase 1 regulation in
opportunities for India the U.S. and Canada in which both the GEM simulation and
As policymakers in India consider developing fuel engine dynamometer testing are mandatory for tractor
efficiency standards for HDVs, one of the fundamental trucks and vocational vehicles (heavy-duty pickup trucks
questions will be how the regulation is designed in terms and vans must be chassis dynamometer tested, similar to
of testing methods and certification pathways. Figure the light-duty vehicle certification process). As discussed in
3 (adapted from Sanchez 2013) shows how the various the previous section, regulators in the U.S. and Canada are
certification frameworks around the world compare in currently deliberating 1) how to integrate transmissions into
terms of the mix of simulation and vehicle testing. On the the program, and 2) whether or not to require engine-spe-
continuum, the upper left represents one extreme in which cific data inputs into GEM as part of the Phase 2 regulation.
simulation is the sole basis for certification. As discussed These developments are represented in option (3).

M
Road od
load Engine
el
fid
el
it y
an
Transmission d
SIMULATION va
China: “Variant” lid
vehicle models at
(1) ‘Full vehicle’ simulation io
n
ch
al
le
ng
? Engine es
Te

+ dynamometer in
s

cr
tin

ea
se
g

SIMULATION HARDWARE Phase 1 rule

co
st

(2) Vehicle simulation + separate engine standard

sa
nd
ca
pi

“Powertrain”
ta

+
li

dynamometer
nv

Option for
es

SIMULATION HARDWARE
Phase 2 rule
tm
en

(3) Vehicle simulation + separate engine standard/powertrain testing

ti
nc
re
as
es

?
“Base” vehicle
HARDWARE models

(4) Chassis dynamometer testing

Figure 3: Continuum of certification pathways

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

As shown by the orange and purple arrows in Figure 3, engine standards disrupt their integrated design process
there is an inherent tradeoff in moving in either direction and limit their ability to pursue the most cost-effective
along the continuum. As we move from the top left to means of reducing fuel use and GHG emissions from the
the bottom right, testing costs and capital expenses vehicles that they produce.
increase, while the burden of simulation model fidelity and
validation decreases (or goes away completely in the case Yet another key issue is the linkage of fuel efficiency
of a regulatory scheme that solely relies on chassis dyna- and criteria pollutant emissions standards. Not having a
mometer testing). Conversely, moving in the opposite separate engine standard could divorce the two standards
and open the door for the possibility of gaming (e.g.,
direction, the trends reverse for both parameters. Where
designing an engine control strategy that produces low
India falls on this continuum is a critical question that
nitrogen oxide (NOX) emissions over the engine cycles
policymakers in India are currently deliberating. We will
but higher NOX over vehicle cycles). It is important to
analyze this issue and provide our recommendations over
keep in mind that standards should promote technologies
the remainder of this section.
and engine optimization strategies that will translate
to real-world fuel savings. This is key for customer
4.1 SEPARATE ENGINE STANDARDS IN INDIA acceptance as well as overall societal benefit.
The issue of whether or not separate engine standards Table 4 summarizes some of the key arguments posited
make sense in the Indian context is perhaps the first by both sides of the debate around the existence of
fundamental regulatory design question that must be separate engine standards.
addressed. The HDV market structure in India is similar
to North America in that there are large independent As evidenced in Table 4, there are valid arguments on
component manufacturers (e.g., independent engine both side of the debate. By introducing some additional
and transmission manufacturers) as well as vertically evaluation criteria, we can provide greater clarity as to
integrated vehicle OEMs. This results in an inherent what testing and certification strategy (or combination
tension amongst these two types of companies. In thereof) makes the most sense for India’s first phase
general, engine manufacturers prefer a separate engine regulation and beyond. The assessment criteria we have
standard so that they have clarity regarding technology chosen and the evaluation matrix are shown below in
investments. Conversely, vehicle OEMs contend that Table 5.

Table 4: Key arguments for and against separate engine standards

For Against
• Maintains linkage of criteria pollutants with CO2 — minimizes • Could promote non-optimal powertrain design — separate
the potential gaming situation in which an engine might be engine standards fail to consider the impact of engine
tuned for low NOX /high CO2 emissions during the engine requirements on vehicle design and vice versa
cycles versus high NOX /low CO2 emissions over vehicle
• Limits compliance flexibility — vehicle OEMs may not be able
cycles and in-use operations
to pursue the most cost-effective pathway to compliance
• Uses existing test procedures — leverages engine cycles,
• Perpetuates inappropriate test cycles — engines are
which industry are very familiar with, in order to minimize the
optimized to the engine certification cycles, which may not
testing burden
accurately represent in-use driving
• Acknowledges the current market structure — allows engines
• Correlates poorly to in-use results — improved efficiency that
to be certified individually and sold into many different
is evidenced on the engine test bench may not translate to
vehicle platforms
real-world fuel savings, depending on the in-use duty cycle
• Can drive improvements in engine and vehicle technologies
— provides engine technology investment clarity for both
independent engine manufacturers and vertically integrated
vehicle manufacturers

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Table 5: Comparison of test procedure options for India

Ability to Timeline for

leverage existing Complexity of regulatory
Certification option testing facilities certification process implementation

5-7 years

Full vehicle simulation – adapted version of VECTO, GEM,

Japan or China model

? 5-7 years

Full vehicle simulation – new India model

5-7 years

Chassis dynamometer

3-5 years

Engine dynamometer

Favorable Moderate Unfavorable

The top two rows represent certification pathways for full to familiarize themselves with simulation modeling and the
vehicles based solely on simulation modeling. The only dis- plethora of other research an engagement required to enact
tinction between the two options is the simulation program full vehicle standards, it is reasonable to estimate that a
that is employed: a currently existing simulation model regulation in India centered around simulation could not be
such as VECTO or GEM (or a slightly modified version for finalized for another 3 to 4 years. Assuming that the industry
adaptation in India), or a completely new model that is needs roughly 3 to 4 years of lead-time after a regulation is
developed specifically for a regulatory program in India. codified before actual implementation, our best estimate
In both cases, there is somewhat limited ability to take is that the process of designing, finalizing, and executing a
advantage of existing testing facilities. Certainly, manufac- simulation-based full vehicle regulation in India would take
turers can utilize existing engine dynamometer capacity roughly 6 to 8 years from now to go into effect.
for developing engine map inputs, but it is unclear whether
or not there are sufficient test track facilities in India to The chassis dynamometer option is unattractive for India
accommodate aerodynamic testing (this is also true for primarily based on the limited number of existing facilities
chassis dynamometer testing, which requires coastdown and the significant capital expenditures and time required
or constant speed testing). Looking at the second criteria, to construct new facilities.
complexity of the certification process, there would likely
be a fairly steep learning curve for manufacturers in India Introducing engine-based standards in India as a first phase
to be able to learn an existing simulation model sufficiently regulation for HDV fuel efficiency is attractive for a number
enough to successfully navigate the entire certification of reasons. This option leverages the strong industry famil-
process. Even if a completely new simulation program is iarity with engine testing and presents minimal testing
developed for India, no matter how simplistic the model and compliance burden to manufacturers. Moreover, a
is in terms in inputs and operation, the fact that it is a new efficiency improvement requirement based on engine
new tool will mean a certain level of learning is required dynamometer testing would not likely require any new
amongst manufacturers and the regulatory community. testing infrastructure. A list of the accredited organizations
Given the long lead-time needed for stakeholders in India in India that do heavy-duty testing is provided in Table 6.

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

The relatively simplistic nature of engine standards 4.2 TRANSITIONING FROM ENGINE STANDARDS
make it such that a regulation could be proposed and TO A MORE COMPREHENSIVE APPROACH
finalized within the next 2 years and then implemented
As engine improvements only represent a subset of the
by the 2020 timeframe. Thus, electing to pursue engine
technologies that are available for improving the efficiency
standards as a first regulatory step maximizes the ability
of HDVs, India will need to transition from an engine testing-
to realize meaningful fuel savings and environmental
based regulation to a more comprehensive ‘full vehicle’
benefits as soon as possible. The primary downside to
approach in order to maximize fuel savings for this sector.
engine standards is that they can potentially yield engines
This more long-term objective must be able to ensure
that are optimized to the test cycles as opposed to being
that technology areas such as aerodynamics, tire rolling
designed to maximize fuel savings during typical vehicle
resistance, transmissions, and weight reduction are included
operations. The extent to which an engine’s actual duty
in the regulatory framework in a manner that makes sense
cycle in real-world driving differs from the standardized
in the Indian context. As discussed in the previous sections,
test cycles will dictate the magnitude if this negative
there are a myriad of different regulatory design and test
impact. However, this issue can be mitigated by intro-
procedure approaches that are available to policymakers
ducing weighting factors to the transient and steady-
in India. Given the challenges and long lead-time needed
state portions of engine cycles such that engines can be
for deciding amongst these options to create protocols for
evaluated to better match what the engine will experience
physical testing and simulation, developing (or adopting)
in an actual HDV such as a tractor truck or transit bus. This
duty cycles, and educating all of the necessary stakeholders
analysis suggests that the benefits of engine standards
about these new procedures, it would be prudent to begin
outweigh the disbenefits, and a first phase regulation
this process as soon as possible. As shown in Figure 4, we
in India centered on engine dynamometer testing is the
recommend that regulators in India actively begin planning
most attractive alternative. Assuming that India develops
the transition to a more comprehensive second phase
engine-based standards using existing engine test cycles,
regulation in parallel to the efforts to design a first phase
there are virtually no technical barriers to finalizing and
regulatory program for engines.
implementing an engine dynamometer-based regulation
by the 2020 timeframe. If regulatory development for engine standards proceeds
such that a proposed rule and then a final regulation can
Table 6: Accredited organizations in India that perform heavy-
duty vehicle testing be established over roughly the next 1-2 years, it seems
reasonable that implementation can begin in the 2020
Organization Location(s) timeframe. This would give manufacturers and the industry
Automotive Research Association as a whole approximately three years of lead-time. In
Pune, Maharashtra
of India (ARAI) addition, as shown in red on the bottom half of the figure,
International Center for Automotive
Gurgaon, Haryana
the process for developing full vehicle standards can
Technology (ICAT) begin in parallel to the regulatory efforts for engines.
Vehicle Research & Development Technical studies to support this process would ideally
Vahannagar, Maharashtra
Establishment (VRDE) include in-depth analyses in the following areas:
Central Farm Machinery Training
Sehore, Madhya Pradesh • Market conditions and anticipated impacts
and Testing Institute (CFMTTI)
Central Institute of Road Transport • Vehicle segmentation
Pune, Maharashtra
(CIRT)
• Technology potential
Indian Institute of Petroleum (IIP) Dehradun, Uttarakhand
• Test procedures and certification pathways
Engine standards

Regulatory Rule proposal Rule

development and finalization implementation

2015 2016 2017 2018 2019 2020 2021 2022 2023

Technical studies, test procedure Regulatory Rule proposal Rule

and simulation development development and finalization implementation

Full vehicle standards

Figure 4: Idealized regulatory timeline for engine and full vehicle standards in India

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

• Flexibility mechanisms • Leveraging existing testing facilities and expertise:

engine dynamometer testing is well understood within
• Compliance and enforcement
industry and the regulatory community. Piggybacking
Following these technical studies, regulatory development on existing criteria pollutant testing will minimize the
of this second phase regulation can begin in earnest towards testing and compliance burden.
the end of the decade, with a proposed and final rule to • Limiting complexity: engine testing is relatively
be released around roughly the same time that engine straightforward when compared to chassis dynamom-
standards are commencing implementation in the 2020 eter and simulation-based certification.
timeframe. As with the engine standards, the regulatory
• Maximizing fuel savings as soon as possible: The
program for full vehicles can be implemented starting
familiarity and relative simplicity of engine testing
approximately three years after the regulation is finalized.
makes it such that a regulatory program and certifica-
tion process centered around engine testing could be
5. Conclusions, recommendations, and
established and implemented in the next 4 to 5 years.
future work Conversely, a regulation built upon any of the other
This study reviewed and summarized HDV fuel efficiency test procedure options (i.e., chassis dynamometer,
regulations around the world and discussed the pivotal role powertrain dynamometer, and/or simulation) would
that test methods and certification pathways play in shaping take much longer to develop and fully implement.
these programs. Given the complexity of the HDV market
and the diversity of commercial vehicle fleet compositions In conjunction with the regulatory development process
and operations around the world, there has been a prolif- for engines, it is imperative that policymakers in India also
eration of different regulatory design and test procedure embark on the many technical and policy analyses that
approaches that have been developed in the countries/ will be required to move beyond engine-only standards
regions that have established HDV efficiency regulations. A to a regulatory approach that promotes improvements
high-level summary of each of these programs is provided across the entire range of technologies available for HDV
in Table 7. fuel savings. By beginning the long-term undertaking of
establishing full vehicle standards in parallel to rulemaking
Examining the various options that are available for activities for engine standards, the transition from an engine-
evaluating the fuel efficiency performance of HDVs, there is only regulation to a more comprehensive approach can be
no option that is clearly superior in terms of costs, complexity, as streamlined as possible.
and accurately representing real-world operations. Each
jurisdiction must balance these various criteria in designing Future work for the ICCT will include assessing the HDV
a regulation that best suits local conditions. market India as well as the technology potential of both
trucks and buses. In addition, we will be conducting
For India, the ICCT recommends that the first phase HDV interviews with a broad cross-section of stakeholders in
fuel efficiency regulation be engine dynamometer-based the HDV industry in India to learn about attitudes, experi-
standards that utilize existing engine test cycles for the ences, and expectations about fuel-saving technologies and
following reasons: practices in the sector.

Table 7: Regulatory design summaries for Japan, the U.S. and Canada, China, and the European Union

Regulatory Categories Certification Test Procedures Metric

• Other Truck (11 subcategories)
• Tractor (2 subcategories) Simulation modeling + engine Fuel economy
Japan
• Route Bus (5 subcategories) dynamometer testing (km/L)
• Other Bus (8 subcategories)

• Tractors Vehicles à Tractors,

HD Pickups Engines
U.S. and • Vocational vehicles simulation model Vocational
Canada • HD pickup trucks and vans Engines à gal/1,000 ton-mi gal/100 mi gal/100 bhp-hr
• Engines (tractors, voc. vehicles) dynamometer testing g/ton-mi g/mi g/kWh
• Tractors “Base” vehicles à
• Dump trucks chassis dynamometer Fuel consumption
China • Rigid trucks
“Variant” vehicles à (L/100 km)
• City buses
• Other buses simulation modeling

Truck and bus categories based

European GHG
on GVWR, chassis configuration, Simulation modeling
Union* (g/tonne-km)
and axle configuration

* Regulatory design is currently under development in the EU. This information represents an upcoming certification program, not necessarily a standard.

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

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TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

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 TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Appendix
100
90
80
Vehicle speed (km/hour)

70
60
50
40
30
20
10
0
0

0
10

20

30

40

50

60

70

80

90

0
17
10

11

12

13

14

15

16

18
Time (seconds)

C-WTVC WHVC

Figure A1: The World Harmonized Vehicle Cycle (WHVC) and the China-World Harmonized Vehicle Cycle (C-WTVC)

Table A1. Commonly used test procedures in the trucking sector

Technology area Metric Test method Example test procedures

Fuel savings Track test, on-road test SAE J1321, SAE J1526
Wind tunnel SAE J1252
Aerodynamics Coefficient of aerodynamic
drag (Cd) reduction Computational fluid dynamics
SAE J2966
(CFD)
Fuel savings Track test, On-road test SAE J1321, SAE J1526
Tire rolling resistance Coefficient of rolling resistance
Laboratory drum test ISO 28580:2009
(Crr) reduction
Track test, on-road test SAE J1321, SAE J1526
Powertrain and driveline Fuel savings Chassis dynamometer SAE J2177
Engine dynamometer 40 CFR 1065

WORKING PAPER 2015-3 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION 19

TESTING METHODS FOR HDV FUEL EFFICIENCY: TRENDS, AND IMPLICATIONS FOR INDIA

Table A2. Regulatory test cycles in Japan, the U.S. and Canada, and China

Country Type Cycle name Description Comments and cycle weightings

Heavy-Duty Urban Designed to simulate Cycle weightings (% urban, interurban)
Test Cycle stop-and-go urban
Tractor trucks < 20 tonnes GVW: 80%, 20%
(JE05 mode) driving
Tractor trucks > 20 tonnes GVW: 90%, 10%
Other trucks < 20 tonnes GVW: 90%, 10%
Japan Vehicle Designed to simulate
Other trucks > 20 tonnes GVW: 70%, 30%
Heavy-Duty Interurban highway driving at a
Test Cycle maximum of 80 kph Transit buses: 100%, 0%
(includes +/- 5% grade)
Other buses < 14 tonnes GVW: 90%, 10%
Other buses > 14 tonnes GVW: 65%, 35%
Transient cycle that
Federal Test Procedure includes segments
(FTP) heavy-duty designed to simulate Vocational vehicle engines tested using the FTP only
Engine transient cycle both urban and highway
driving
Supplemental Emissions 13-mode steady state
Tractor truck engines test using the SET only
Test (SET) test
U.S. and Heavy Heavy-Duty Designed to simulate
Canada Diesel Truck (HHDDT) stop-and-go urban
Cycle weightings (% transient, 55 mph, 65 mph)
transient cycle driving
Sleep cab tractor trucks: 5%, 9%, 86%
Designed to simulate
Vehicle 55 mph cruise highway driving at a Day cab tractor trucks: 19%, 17%, 64%
maximum of 55 mph
Vocational vehicles: 75%, 9%, 16%
Designed to simulate
65 mph cruise highway driving at a
maximum of 65 mph
Cycle weightings (% urban, interurban, highway)
Tractor trucks < 25 tonnes GVW: 0%, 40%, 60%
Tractor trucks > 25 tonnes GVW: 10%, 90%
Dump trucks > 3.5 tonnes GVW: 0%, 100%, 0%
Slightly modified
version of the World Other trucks < 5.5 tonnes GVW: 40%, 40%, 20%
China-World Harmonized Vehicle Other trucks 5.5-12 tonnes GVW: 10%, 60%, 30%
China Vehicle Harmonized Vehicle Cycle. Meant to better
Cycle (C-WTVC) reflect the duty cycles Other trucks 12.5-24.5 tonnes GVW: 10%, 40%, 50%
of Chinese commercial Other trucks > 24.5 tonnes GVW: 10%, 30%, 60%
vehicles.
Transit buses > 3.5 tonnes GVW: 100%, 0%, 0%
Other buses 3.5-5.5 tonnes GVW: 50%, 25%, 25%
Other buses 5.5-12.5 tonnes GVW: 20%, 30%, 50%
Other buses > 12.5 tonnes GVW: 10%, 20%, 70%

20 INTERNATIONAL COUNCIL ON CLEAN TRANSPORTATION  WORKING PAPER 2015-3