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AADT Estimation with Regression Using Centrality and Roadway Characteristic Variables

2017, Transportation Research Board 96th Annual MeetingTransportation Research Board

Clemson University TigerPrints All Theses Theses 5-2017 Annual Average Daily Traffic (AADT) Estimation with Regression Using Centrality and Roadway Characteristic Variables McKenzie Keehan Clemson University, mkeehan@clemson.edu Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Recommended Citation Keehan, McKenzie, "Annual Average Daily Traffic (AADT) Estimation with Regression Using Centrality and Roadway Characteristic Variables" (2017). All Theses. 2644. https://tigerprints.clemson.edu/all_theses/2644 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact kokeefe@clemson.edu. ANNUAL AVERAGE DAILY TRAFFIC (AADT) ESTIMATION WITH REGRESSION USING CENTRALITY AND ROADWAY CHARACTERISTIC VARIABLES A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Civil Engineering by McKenzie Keehan May 2017 Accepted by: Mashrur Chowdry, Committee Chair Wayne Sarasua Eric Morris ABSTRACT Accurate estimation of annual average daily traffic (AADT) is critical in nearly every roadway decision, such as allocations of funding for roadway improvements and maintenance. While some roadway locations have permanent count stations capable of counting vehicles 24-hours a day throughout the entire year, they are typically only installed at selected locations on major roadways (i.e., freeways and major arterials) with high traffic volumes. On lower functional class roads and roadway segments on higher functional class roads without permanent count stations, short-term coverage counts are collected and adjusted with data from permanent count stations to estimate AADT. Short-term coverage counts are essential because they provide data from roadways of all functional classes and lane configurations, accounting for varying volumes on all roads maintained by an agency. Although necessary, coverage counts can be expensive and can exhaust resources such as investment in data collection workforce, equipment and data analysis. This study develops a strategy for estimating AADT on every roadway within a given jurisdiction using permanent count stations and short term coverage counts, while limiting the number of coverage counts needed. The goal of this thesis is to illustrate a noteworthy time and cost savings using a new centrality based AADT estimation method. A set of new deterministic variables, based on the theory of centrality, are introduced. This study revealed that estimated root mean square error (RMSE) for the new centrality based AADT method is half of the estimated RMSE in the travel demand based AADT model for the same area. Additionally, it was found that using centrality based AADT estimation model, the number of coverage count stations necessary can be reduced by more than 60% compared to the ii standard factor method for AADT estimation without compromising the AADT estimation accuracy. iii DEDICATION I would like to dedicate this thesis to my mother and father, for their unconditional love and support. iv ACKNOWLEDGMENTS I would like to express so much gratitude and appreciation to my advisor, Dr. Mashrur Chowdhury, for constantly challenging me and aiding in my growth as a researcher and graduate student. During my last two years under his wing, I have seen myself evolve in ways I could have never imagined, and it has been due to his relentless support and guidance. He has helped me to exceed expectations I had previously set for myself, and has helped me to realize that there are no limitations to our potential. I would also like to thank Dr. Wayne Sarasua and Dr. Eric Morris for serving as my thesis committee members, and providing valuable feedback throughout my research. Dr. Sarasua has also taught me in several courses and has proved to be a passionate professor who cares deeply about the success of each of his students. I appreciate the administrative staff members from the Glenn Department of Civil Engineering, including Kristi Baker, Sandi Priddy, CJ Bolding, Karen Lanning, and Monica Hughes, for helping me with all of the managerial and organizational aspects of my position and my needs as a student. I would like to extend my deep appreciation to Dr. Kakan Dey for being an amazing mentor through his continuous effort to improve the research quality and for always being there whenever I needed him. I would like to thank Md Mizanur Rahman, Sakib Kahn, and Sababa Islam, for being the best mentors a fellow student could ask for. Their kindness and expertise have done so much for me as I student and I would not have been able to be as successful in my student career if not for them. Moreover, I would like to thank Md Mhafuzul v Islam and Md Zadid khan for helping me with many projects, including class projects, competitions, and presentations, which were all made better due to their help and guidance. I would like to thank the South Carolina Department of Transportation (SCDOT) for funding a lot of the work I’ve done throughout my graduate student career, and providing me with the data that were necessary for my research. I cordially thank my parents, my siblings, and my entire family for being the support system for me during any critical times. They have always been my inspiration to reach my goals. vi TABLE OF CONTENTS Page TITLE PAGE .................................................................................................................. i ABSTRACT .................................................................................................................... ii DEDICATION............................................................................................................... iv ACKOWNLEDGEMENTS .......................................................................................... v TABLE OF CONTENTS ............................................................................................ vii LIST OF FIGURES ...................................................................................................... ix LIST OF TABLES ......................................................................................................... x INTRODUCTION.......................................................................................................... 1 1.1 Problem Statement.............................................................................................. 1 1.2 Objective of the Thesis........................................................................................ 2 1.3 Organization of the Thesis ................................................................................. 2 LITERATURE REVIEW ............................................................................................. 4 2.1 Overview ............................................................................................................... 4 2.2 AADT Estimation Methods................................................................................. 4 2.3 AADT Estimation through Centrality ............................................................... 9 RESEARCH METHOD .............................................................................................. 11 ANALYSIS AND RESULTS ...................................................................................... 21 4.1 AADT Estimation Using Centrality and Linear Regression ......................... 21 4.2 Comparison of AADT Estimation using Centrality based Model and Traditional Travel Demand Model Output ........................................................... 23 vii Table of Contents (Continued) Page 4.3 Possibility of Reduction of Coverage Counts using Centrality based AADT Method ...................................................................................................................... 26 4.4 Cost Savings Analysis ........................................................................................ 29 CONCLUSIONS AND RECOMMENDATIONS ..................................................... 32 5.1 Conclusions ......................................................................................................... 32 5.2 Recommendations .............................................................................................. 33 REFERENCES............................................................................................................. 36 APPENDIX A .............................................................................................................. A1 viii LIST OF FIGURES Page FIGURE 1 Method of Origin-Destination Centrality Calculation .......................... 11 FIGURE 2 Map of External Gateway Points ............................................................ 14 FIGURE 3 Greenville Parcels with Relative Weights .............................................. 16 FIGURE 4 External-to-External Centrality Map ..................................................... 17 FIGURE 5 Internal-to-External Centrality Map...................................................... 17 FIGURE 6 Internal-to-Internal Centrality Map ...................................................... 18 FIGURE 7 Comparison of AADT Estimation Methods ........................................... 23 FIGURE 8 Method to Determine Coverage Count Reduction Potential................ 24 FIGURE 9 Reduction of Coverage Counts by Using the Centrality Method ........ 26 ix LIST OF TABLES Page TABLE 1 Shapefiles and Attributes Used in the Model Development ................... 12 TABLE 2 Three Stress Centrality Types and Associated Inputs ............................ 15 TABLE 3 Regression Summary Statistics ................................................................. 20 TABLE 4 Comparison of Model Inputs for Centrality Method and TDF Model . 21 TABLE 5 Comparison of Model Steps for Centrality Method and TDF Model ... 21 TABLE 6 Trials for Reduction of Coverage Counts ................................................ 25 TABLE 7 Cost Savings Analysis................................................................................. 27 x CHAPTER ONE INTRODUCTION 1.1 Problem Statement Annual average daily traffic (AADT) is defined as the average daily measure of the total volume of vehicles on a roadway segment over a year. Traffic volumes are the lead indication travel demand and utilization of the roadways within a specified network (1, 2). Therefore, accurate traffic volume estimations are critical in nearly every roadway decision. While some roadway locations have permanent count stations capable of collecting vehicle volumes 24-hours a day throughout the entire year, they are very costly to implement and maintain, and are typically only provided at selected roadway segments. Therefore, short term coverage counts are taken at thousands of strategically placed roadway segments of all functional classes and lane configurations, accounting for varying volumes on the roads maintained by an agency (3). The counts at these locations are usually only collected once a year or every few years with pneumatic tubes, and the data collection period can last from 24 hours to 7 days, depending on the responsible transportation agency’s policy and reporting requirements (3, 4). For short-term count stations, the permanent count stations serve as control counts, and are used to determine daily, monthly, and seasonal factors to calibrate the data collected at short-term count stations in estimating AADT. However, operating and estimating AADT using coverage counts can be expensive and can exhaust a significant amount of resources in terms of manpower, equipment, and 1 data analysis. In addition, the data provided by these counts is limited, and not always sufficient in predicting accurate AADT values. For example, a 24-hour count on one day throughout the entire year may need to be used to calculate AADT using only the one count and calculated daily and monthly factors using the factor method, as further explained in the Chapter 2: Literature Review. Any inconsistencies between the day’s data and the other elements of that day and month may result in inaccurate AADT estimation. 1.2 Objective of the Thesis This thesis aims to develop a unique means of estimating AADT on roadways within a given jurisdiction, while limiting the required amount of implementation time and effort. All of the data used in development of the AADT estimation method is readily available. The motivation for this research is to develop an AADT estimation method, which any jurisdiction can implement with minimal time and effort. 1.3 Organization of the Thesis Chapter 2 describes the background research and literature on the currently available AADT estimation methods. Some of these methods are currently being utilized by state and local transportation agencies, while others are simply being used in academia for research purposes. Additionally, Chapter 2 discusses the theory of centrality, its applications, and its potential in AADT estimation. Chapter 3 discusses the method for applying the theory of centrality in AADT estimation used in this thesis. The steps used in the application are outlined and explained in detail. 2 Chapter 4 provides a detailed explanation of the linear regression model produced by this method. Additionally, Chapter 4 compares the newly developed model to an existing travel demand forecasting model for the city, both conceptually and statistically. Next in Chapter 4, a procedure is performed in order to determine if this method could reduce the number of short term count stations that the city of Greenville should use in order to produce AADT estimates for all current short term count locations. Finally in Chapter 4, a cost savings analysis is performed to determine the financial competence of this method. Chapter 5 concludes this thesis, offering conclusions and recommendations for further research. 3 CHAPTER TWO LITERATURE REVIEW 2.1 Overview Because quality AADT estimation on local roads is vital, ample amounts of research have been carried out in order for models to be developed that can adequately estimate the AADT of every roadway within a given area (2,5,6), which is discussed further in this chapter. It is important to note the amount of time and costs associated with these often inaccurate or inconsistent methods. In this chapter we have reviewed AADT estimation methods and the theory of centrality, as well as its feasibility in AADT estimation. 2.2 AADT Estimation Methods Although collecting traffic count data every day in a year is the most accurate method of calculating AADT, it is not economically feasible to install and maintain data collection systems on a widespread scale. Traditionally, for roadways without permanent count stations, AADT is calculated using the America Association of State Highway and Transportation Official’s (AASHTO’s) factor method. Using this method, daily and monthly factors are calculated using permanent counts stations, and typically each permanent counts station is associated with a group of short term count locations, based on clustering. 24-hour traffic counts from short term count stations are then multiplied with the adjustment factors to find AADT, as shown in the following equation: 4 Eqn. 1 where V24ab = 24-hour volume for day a in month b (vehs); DFa = daily adjustment factor for day a; and MFb = monthly adjustment factor for month b (1). Another AADT estimation method, used by some states and implemented in programs such as the Traffic Count Database System (7), used additional factors such as a seasonal factor and an axelcorrection factor, as shown in the following equation: Eqn. 2 where V24ab = 24-hour volume for day a in month b (vehs); SFab = seasonal adjustment factor for day a and month b; and AFc = applicable axel-correction factor for c number of axels (7). However, these formulas can only be used on roadway segments that have short term count locations, which are not used to collect data on most publically maintained roadways within a given state or jurisdiction. Therefore, ample amounts of research have been carried out in order for models to be developed that can adequately estimate the AADT of every roadway within a given area (2,5,6). Several studies have shown that linear regression that utilizes roadway characteristics and socioeconomic factors at short term count locations can be used to estimate AADT (2,5,6,8). Doustmohammadi et al. developed a linear regression model to calculate AADT using a variety of socio-economic factors and roadway data for small and medium sized urban communities in Alabama (5). The significant variables identified in the final two models (one for a small city and one for a large city) included the functional classification (FCLASS) and lane counts of roadway segments (LANE), in addition to 5 population, retail employment (RETAILEMBUFF), and all-other employment (NONRETAILEMBUFF) all inside a 0.25 mile radius around the traffic count site. These two models are shown below: Model 1 (R2 = 0.82): AADT = -5625 + 8493 FCLASS + 219 LANE - 1.16 POPBUFF -0.58 NONRETAILEMBUFF + 11.55 RETAILEMBUFF Model 2 (R2 = 0.79): AADT = -12590 + 4479 FCLASS - 1.15 POPBUFF – 0.86 NONRETAILEMBUFF +7.91 RETAILEMBUFF It was concluded that their AADT estimation models can accurately estimate AADT on desired roadways in cities of similar populations (5). However, the accuracy and means of collecting the socio-economic factors used are resource intensive and difficult for annually updating AADT. For example, the population data was obtained from the Census Department, where data is only updated every 5 years (9). In this study, the other two socioeconomic factors - retail and all-other employment – were found from case studies that were completed as a part of long-range transportation plans recently completed by a third party organization. This socio-economic data can be time consuming to collect, and relies on sources not maintained by the DOT. Additionally, socio-economic factors determined by surveys or sampling may not be accurate or capable of validation. Zhao et al. used regression and further statistical analysis to find factors supplemental to AADT estimation in a study conducted for Florida. The study used geographic information system (GIS) technology to investigate various factors that may be good predictor of AADT on a road (2). A variety of land-use and accessibility measurements were developed and tested in (2). The four models developed achieved R2 6 values from 0.66 to 0.82. The variables for each are: i) Model 1: Lane count, functional class, access to employment centers, directness of access to expressways, and employment inside a 0.25 mile radius (R2= 0.8180); ii) Model 2: Lane count, access to employment centers, directness of expressway access, and network distance to the mean centers of population (R2= 0.6607); iii) Model 3: Lane count, access to regional employment centers, directness of expressway access, network distance to the regional mean centers of population, and population inside a 0.25 mile radius around a traffic count site (R2= 0.7624); and iv) Model 4: Lane count, access to regional employment centers, directness of expressway access, network distance to the regional mean centers of population, employment inside a 0.25 mile radius around a traffic count site, and population inside a 0.25 mile radius around a traffic count site (R2= 0.7648). During their data collection efforts, the author used employment data, which was purchased from a third party, containing the number of employees at each business location and the standard industrial classification code. In this case, the data had been purchased for a prior project, however, for most DOTs, implementing this method would not only require attaining or purchasing additional data not readily available to their agency, but also relying on data not operated and maintained by the DOT and only updated at the third party’s discretion. Wang et al. presented a means to estimate AADT for roadways through travel demand forecasting (6). A main factor of applying the travel demand model involved using land-use data at the parcel level to determine estimated trips produced from or attracted to each parcel. All-or-nothing trip assignment was conducted using free-flow travel times. Then, the trips were dispersed through a trip distribution gravity model at the parcel-level. 7 The results show that the proposed model generated 52% MAPE, which is 159% lower than the MAPE from regression models ran for the same area (6). While travel demand modeling methods have proven accurate in AADT estimation, they are often time consuming to develop and require a lot of data collection resources and modeling expertise. The classic four step travel demand model is complex, time consuming, and costly for many jurisdictions. This is explained in much further detail in the Chapter 4: Results and Analysis, where the newly developed model is compared to an existing Travel Demand Model. Artificial Neural Networks are also commonly utilized as a means to find AADT on roadways. Sharma et al. developed two models for estimating AADT using an Artificial Neural Network – one using the previous 48-hour count data and one using the previous two 48-hour count data (10). When compared to the traditional factor model, the artificial neural network models proved to be less accurate. However, an advantage of the neural network models is that they did not require the ATRs to be grouped, unlike in the factor method. The study found that the errors of AADT estimation using the factor approach could be lowered by grouping the ATR sites appropriately and accurately assigning shortterm count stations to each ATR site. For two 48-hour counts, the 95th-percentile error is between 14.14 to 16.68 percent, as compared with the range of 16.77 to 24.89 percent for a single 48-hour count. While their results are adequate, many practicing traffic engineers find the neural network approach to be more complex than the existing factor approach due to lack of expertize. 8 In emerging Connected Vehicle Technology where vehicles continuously send data to roadside infrastructure through a wireless communication medium potentially could reduce the needs of permanent as well as coverage count stations for collecting traffic volume data (11, 12). Although it will be several more years before enough connected vehicles on different road segments reduce the need for count stations for volume data collection, they potentially are considered as potentially an economically beneficial data collection strategy (13). 2.3 AADT Estimation through Centrality Land-use characteristics at the parcel level have been incorporated in several AADT estimation models (8, 14). Centrality models, for example, seek to apply numerical values to the topological significance of each element in a network using land-use characteristics. Centrality is used in graph theory and network analysis in order to identify the level of importance of certain elements of a graph or network. A network in this case is broadly defined, and can refer to street networks, urban networks, and even social networks (15). In 2012, Zhang et al. developed a model based on road network patterns and traffic analysis zones using three types of centrality - betweenness centrality, degree centrality, and closeness centrality (14). The betweenness centrality of a node is the count of the times that the node is intersected by all of the “shortest paths” within the network – when considering the paths from every node in the network to every other node in the network. Degree centrality of a node is the count of the number of other nodes that are adjacent to 9 it, and with which it is, therefore, in direct contact. Closeness centrality of a node is based upon the degree to which a point is close to all other points. The greater the closeness centrality of a node is, the closer the node is to all others within the network. Zhang et al.’s study used a centrality property of the whole network, based on the node centralities calculated, to find the each type of network centrality – betweenness, degree, and closeness. It was found that network betweenness centrality was the most accurate in distinguishing and describing various Traffic Analysis Zone (TAZ) road network patterns (14). Most recent approaches for estimating AADT use a modified form of stress centrality. Stress centrality is defined as the total count of the times a link would be used if one were to travel from every node to every other node via the shortest path in a network. Lowry introduced a new metric called origin-destination (OD) centrality that can be used in linear regression as a contributing variable to calculate AADT spatially (8). Finding OD centrality can be executed using a geographic information system (GIS) platform and less data than other methods require, including land use data and the street network. A case study of this concept yielded an R2 of 0.95. AADT can vary greatly among roadway segments of the same functional classification, and this method can demonstrate significant variation along roadway segments of the same functional class (8). There are several benefits of using centrality concepts in estimating AADT. First, the concept is simple and can be realistically applied to any given network, without the use of expensive, proprietary, and/or subjective data. Also, to derive centrality measures, a GIS program is essentially the only required tool. Not only can this entire model can be 10 completed within a short time period, but it has the potential to reduce the number of coverage counts needed to accurately estimate AADT. In this research, the author was motivated to investigate if the centrality method utilized on a small city could be applied to a medium size city, and determine if the model would benefit from the inclusion of additional variables, rather than the centrality variables alone (16). 11 CHAPTER THREE RESEARCH METHOD Opting to use only data that is readily available to South Carolina DOT, this study attempts to find new deterministic variables to calculate AADT on roadways in a medium size city (population roughly 65,000) based on the theory of centrality. A similar study was conducted for the small city of Mascow, Idaho (population of roughly 24,000) (7). Our study area, the city of Greenville, SC currently has 6 automatic traffic recorders (ATRs) and 153 short-term count locations within the city limits. The main objective of this particular research was to apply origin-destination centrality to the city as a means to find new variables to estimate AADT that are statistically significant at least 95% (pvalue<0.05). To expand off of the discussion in the Literature Review, origin-destination centrality is a type of centrality that is derived from stress centrality. Stress centrality is defined as the total count of the times a link would be used if one were to travel from every node to every other node via the shortest path in a network. In terms of calculating stress centrality, the stress centrality equation of a link within a network is given below: Eqn. 3 ∑ ∈ where V = the set of all zones in a network, σij = the shortest route from node i to node j, and σij(e) = 1 if link e is used in this path and σij(e) = 0 if link e is not used in the shortest path. This stress centrality would be based on three types of travel in or through a city: 12 Internal-to-Internal, Internal to External, and External to External. These will be explained further in Step 5, later in this chapter. FIGURE 1 METHOD OF ORIGIN-DESTINATION CENTRALITY CALCULATION Unlike stress centrality, the origin-destination centrality of a link uses relative weights of the TAZs and gateways in each origin-destination combination. Additionally, the theory of centrality assumes all links are of the same size, and does not take into account the capacity of each. Therefore, this O-D centrality of each link is actually significant only per lane. Therefore, we will incorporate the number of lanes into the equation, making it simply: 13 Eqn. 4 ∑ ∈ where N = is the number of lanes on link e, V = the set of all zones in a network, σij = the shortest route from node i to node j, σij(e) = 1 if link e is used in the path and σij(e) = 0 if link e is not used in the shortest path, Wi = the relative weight of origin I, and Wj = the relative weight of destination j. A “node” in this instance will refer to either a TAZ or a gateway. The majority of the steps (Steps 1-5 and Step 7) included in this research effort were performed through a GIS software. All of the data used in the new model development are publically accessible, updated at least once annually. The base data used in the model development was collected from the City of Greenville, SC’s GIS Data website (17) and the ITE Trip Generation Manual (18). This method does not require any additional data collection or cost for the purchasing of data from private organizations. The data used are geocoded in GIS shapefiles for the data sets shown in Table 1 below. TABLE 1 Shapefiles and Attributes used in the Model Development Shapefile Street Centerlines Parcels Zoning Count Station Locations Notable Attributes Street Name, Functional Class, Speed Limit, Number of Lanes Parcel Number, Number of Buildings, Building SF, Parcel Area Zone Number, Zoning Code Station Number, Count Data Step 1: Develop Street Network First, the polyline shapefile of the street network, titled “Street Centerlines” was used to develop a street network for the City of Greenville, SC. The ESRI ArcGIS extension, “Network Analyst”, has a tool called “Create Network Dataset” that can easily 14 convert a shapefile to a network. When using ArcGIS to make routing decisions, it is essential to first convert a polyline shapefile to a network of links. Step 2: Create Traffic Analysis Zones (TAZs) Much like travel demand models, the stress centrality and origin-destination centrality models are composed of Traffic Analysis Zones (TAZs). The “Parcels” shapefile contains land use attributes such as land area (acre), land use type, number of buildings, etc. Each TAZ is composed of multiple adjacent parcels based on geometry, land use type, and roadway access. Within the city limits of Greenville, SC, the parcels were sorted into 1,262 zones. Step 3: Create TAZ Centroids The area (acre), land use type, number of buildings, building square feet, and others are all specified in the shapefile’s attributes for each of the parcels. Given these attributes, combined with trip generation data from the ITE Trip Generation Manual (18), each parcel is assigned its own relative weight, by calculating daily trip generation rate for each TAZ, as shown in Figure 2. For example, if a parcel’s land use was identified as a single family residence, the daily trip generation rate from the Trip Generation Manual, in this case 9.5 trips per dwelling unit, would be multiplied by the number of dwelling units within that parcel, giving that parcel a relative trip generation rate. Centroids for each zone are established through a weighted mean analysis based on the geometry and weight of each parcel within a zone. The weighted mean is essentially 15 the centroid of the zone taken as the mean center of all of the parcels within the TAZ, except instead of each of the parcels contributing equally to the center, some parcels contribute more than others based on relative trip generation rates. Step 4: Create External Entry and Exit Points Because the utilized methods of centrality use travel that can begin and/or end outside of the city limits, external points of entry and exit to the city are established by examining all potential major exit/entry roadways. Just outside of the city limits of Greenville, 32 major points of entry or exit are identified. FIGURE 2 Eternal Gateway Points 16 Step 5: Determine the Shortest Route between TAZs and Gateway Points Once all internal TAZ centroid and external points are established, the shortest routes between each origin-destination combination are determined. Table 2 below shows the inputs required for each routing type. Using the previously created Network in ArcGIS, the shortest distance between all of the points in a given dataset can be found through the use of the “Closest Facility” tool in the Network Analyst extension. The output of the tool produces routes between each origin-destination combinations established. TABLE 2 Three Centrality Types and Associated Inputs Stress Centrality Method Internal ‐ Internal Internal ‐ External External ‐ External Inputs Origins Destinations Zone Centroids Zone Centroids Zone Centroids External Points External Points External Points Travel throughout a city (i.e., jurisdiction under consideration for modeling) is based on three types of origin-destination combinations: 1) Internal-to-Internal (I-I): Trips from one travel analysis zone (TAZ) to another travel analysis zone within the city; 2) Internal-to-and-from-External (I-E): Trips from one travel analysis zone to a destination outside of the city limits, or vice versa; 3) External-to-External (E-E): Trips from an origin outside the city limits to a destination outside of the city limits, that requires traveling through the city 17 Step 6: Assign Weights to Each TAZ and External Point As in determining the stress centrality for each type of origin-destination combination, finding the origin-destination centrality began with creating a street network dataset, TAZs, and external exit/entry points. In this method, each zone’s weight is determined by summing the weights of all of the parcels within that zone, which were established in Step 3. The relative weight of each external point (E) is then taken as the nearest AADT value available on that roadway. FIGURE 3 Greenville Parcels with Relative Weights 18 Step 7: Create Three Origin-Destination Centrality Models The three models are created using the origin-destination travel combinations: I-I, I-E, and E-E. Their outputs incorporate the weights created in Step 5 above. The three new origin-destination centrality maps are shown in Figure 4, Figure 5, and Figure 6. The findings of the analysis are explained in the Chapter 4: Results and Analysis. FIGURE 4 EXTERNAL-TO-EXTERNAL CENTRALITY MAP 19 FIGURE 5 Internal-to-External Centrality Map 20 FIGURE 6 Internal-to-Internal Centrality Map Step 8: Create Regression Model to Estimate AADT Using the outputs of the stress centrality formula above for each link and each type of stress centrality, the three new variables were calculated as potential independent variables in AADT multiple linear regression and non-linear regression model development. Other variables were incorporated in an attempt to produce the most accurate model are speed, number of lanes, and functional class. These methods and the findings of the analysis are explained in Chapter 4: Results and Analysis. 21 CHAPTER FOUR ANALYSIS AND RESULTS 4.1 AADT Estimation Using Centrality and Linear Regression Once the three new origin-destination centrality were calculated following the steps presented in Chapter 3: Research Method, multiple linear regression analysis was performed with these three and three roadway characteristic variables, in order to develop the most accurate centrality based AADT estimation model. The six independent variables considered are: i. I-I Origin-Destination Centrality (I-I OD) ii. I-E Origin-Destination Centrality (I-E OD) iii. E-E Origin-Destination Centrality (E-E OD) iv. Functional Classification (FC) 5 - Interstate 4 - Major Arterial Freeway/Expressway 3 - Major Arterial 2 - Minor Arterial, Major Collector 1 - Minor Collector v. Speed Limit (SL) The centrality variables were combined with roadway characteristic variables (i.e., speed, functional class and number of lanes) with the goal to derive new variables that could prove to be independent variables for AADT estimation model. The final regression model is shown in Table 3 below. 22 TABLE 3 Regression Analysis Summary Statistics Regression Statistics Multiple R 0.910628468 R Square 0.829244206 Adjusted R Square 0.825851707 Standard Error 4828.530729 Observations 155 ANOVA df Regression Residual Total Intercept I-I OD E-E OD Speed 3 151 154 Coefficients -18267.96215 3.12073E-06 0.001284391 712.4749964 SS 17096765045 3520521060 20617286105 Standard Error 2496.893055 4.95513E-07 0.000124769 77.96341866 MS 5698921682 23314709 F 244.4346 Significance F 9.9506E-58 P-value 1.39986E-11 3.12489E-09 3.68774E-19 3.94468E-16 Due to these results, the formula below was selected as the best formula: AADT = 3.12073E-06* I-I OD + 1.284391E-04 *E-E OD+ 712.4749964 SL – 18267.96215 As shown, I-E OD centrality was not used in this final model. This is because, due to the nature of the three models, I-E OD centrality was too similar to E-E centrality and I-I OD centrality to provide statistical significance in the final model. The coefficient of I-I Centrality is much lower than that of E-E Centrality, because the values used for I-I centrality were much larger than those used for E-E Centrality. The coefficients for all variables used are positive, showing a positive correlation with AADT. Additionally, the p-values for each of the variables used are all significant at greater than 99% (p-value < 23 0.001). Finally, the intercept is a very large negative value, which is also not surprising, due to the large values of these variables. 4.2 Comparison of AADT Estimation using Centrality based Model and Traditional Travel Demand Model Output In order to validate the accuracy of the centrality based AADT estimation model, the author compared the model’s predictive ability with that of the city’s existing travel demand model. First, it is important to carefully specify the differences between the steps and data necessary to use the two models. Travel demand forecasting models consists of four major steps: Trip generation, trip distribution, mode choice, and trip assignment (19). Time-of-day and directional factoring is a very important step as well, but is not explicitly mentioned in four steps of the “four-step” model. For example, in the four step model, ample amount of data inputs are necessary prior to the initiation of the four steps, which can include, but are not limited to, employees, students, automobiles, and households by TAZ. In addition, there are two ends of any trip generation – trip productions and trip attractions – and all trips must have a given purpose – Home-based Work (HBW), Home-based Other (HBO), and Non Homebased (NHB). Considering both trip productions and attractions, in addition to each purpose, there are six types of formulas that must be used for each TAZ in order to calculate the overall trip production and attraction of each TAZ. Then, once the formulas are estimated and the trip productions and attractions are calculated, the number of attractions must be balanced to the number of productions (19). The trips for Internal-to-External and External-to-External travel are then calculated separately. Table 4 and Table 5 below compare more of the inputs and steps of each of the models. 24 TABLE 4 Comparison of Model Inputs for Centrality Method and TDF Model Model Inputs Street Network Street Data (Name, Number of Lanes, Speed, etc.) Employees by TAZ Students by TAZ Automobile by TAZ Households by TAZ Centrality Method x x x Travel Demand Forecasting Model x x x x x x TABLE 5 Comparison of Model Steps for Centrality Method and TDF Model Model Steps Develop Street Network Create Traffic Analysis Zones (TAZs) Create TAZ Centroids Create External Entry and Exit Points Assign Weights to TAZs and External Points Generate Trip Productions by Purpose and TAZ Generate Trip Productions by Purpose and TAZ Balance Number of Attractions to Productions Generate Trips for Internal‐to‐External Travel Generate Trips by Gateway for External‐to‐External Travel Generate Production & Attraction Trip Tables by Purpose Transpose Table to Create Origin‐Destination Tables by Purpose Create a QuickSum Matrix Direct Traffic between all TAZ pairs using Trip Assignment Direct Traffic between all gateway and TAZ pairs using trip assignment Create Three Origin‐Designation Centrality Models Create Regression Model to Estimate AADT Centrality Method x x x x x x x x x Travel Demand Forecasting Model x x x x x x x x x x x x x x x The Base AADT estimates used in Figure 7 are based on observations from 149 short-term count locations in the City of Greenville. Base AADT data was calculated using 25 adjustment factors and short term count data collected by SCDOT. The travel demand model was created by a third party for the Greenville Metropolitan Planning Organization (MPO) for year 2010. Average growth rates from the 6 ATRs located in the City of Greenville were used to estimate the 2015 volumes from the travel demand model’s calibrated volumes for 2010. The comparison of the AADT estimates for short term count stations using two models (i.e., centrality based AADT method, and AADT from travel demand model) is shown in Figure 7. It is important to note that both the origin-destination centrality model and the travel demand model were calibrated using the estimated AADT using the factor approach and 24-hour count for each short-term count station. The travel demand model achieved lower goodness-of-fit (i.e., R2 value of 0.61), while the new centrality based AADT method developed in this research has higher goodness-of-fit (i.e., R2 value of 0.77). Additionally, the root mean square error (RMSE) for the centrality-based AADT linear regression model and the travel demand based AADT model are 7352.54 and 14073.19 respectively. It could be concluded that centrality based AADT method performs better compared to AADT estimate from travel demand model in terms of RMSE and R2. 26 120000 Travel Demand Model Origin‐Destination Centrality Model BASE AADT VALUES 100000 80000 y = 1.4132x ‐ 3035.8 R² = 0.6147 60000 y = x ‐ 3E‐12 R² = 0.8292 40000 20000 0 0 10000 20000 30000 40000 50000 60000 PREDICTED AADT VALUES FIGURE 7 Comparison of AADT Estimation Methods 4.3 Possibility of Reduction of Coverage Counts using centrality based AADT Method In an attempt to explore if the number of short-term count locations maintained throughout the city could be reduced applying centrality based AADT estimation method, random sub-sets of short term count were used to determine how many short-term stations were necessary to achieve same level of AADT estimation for all roads in the city. Five random sub-sets of each scenario were used, and the scenarios consisted of 100%, 80%, 60%, 40% and 20% of the total short term count stations in the city of Greenville. In each random sub-set, two thirds of the data were used for model calibration and the other third was used for model validation. This is shown in further detail in Figure 8 below, for clarification. 27 FIGURE 8 Method to Determine Coverage Count Reduction Potential After the model of the calibration set was developed, the validation set was ran using the same linear regression model. Then the Median Absolute Percent Error (MdAPE) of the calibration and validation data sets were calculated. This process was repeated 5 times for each scenario. The results of each trial in each scenario are shown in Table 6 below. As demonstrated in Figure 9, after using more than 60 short-term count stations (40% of 28 current short-term count stations), little AADT estimation accuracy is gained in terms of MdAPE, suggesting that the number of coverage counts used in the modeling can be reduced by 60%, which could substantially reduce data collection cost for the SCDOT. The author believes this method can further save DOTs resources without compromising model accuracy. A cost savings analysis is performed later in this chapter. TABLE 6 Trials for Reduction of Coverage Counts Percentage of Count Stations 100 80 60 40 20 Trial Number Validation Data MdAPE 1 2 3 4 Calibration Data MdAPE 55.264 57.391 59.166 59.331 5 1 2 3 4 64.716 56.670 59.967 58.667 64.045 62.194 5 1 2 3 4 58.784 53.213 58.629 45.903 63.355 70.419 5 1 2 3 4 5 1 2 3 4 5 65.522 54.727 38.788 62.132 59.158 60.729 68.901 64.788 45.558 38.878 67.126 29 92.253 97.678 64.559 66.062 60.501 56.790 64.027 47.361 61.825 54.766 72.636 53.099 64.652 79.689 69.292 58.174 51.264 111.861 96.816 59.709 195.504 90.297 57.824 120 Calibration Data (67%) Median Absolute Percent Error 100 Validation Data (33%) 80 60 40 20 0 100 80 60 40 20 Number of Short Term Count Stations FIGURE 9 Reduction of Coverage Counts Applying the Centrality Method 4.4 Cost Savings Analysis Because the centrality based AADT method has the potential to reduce the number of short-term count stations, a cost savings analysis was performed to estimate annual savings for the South Carolina Department of Transportation by using this method throughout the state. SCDOT performs 12,000 short-term counts per year, each collecting 24 hour volume data. Due to the estimated reduction of over 60% short-term counts in Greenville applying centrality based AADT method cost savings analyses was performed for 40%, 50%, 60%, and 70% short-term count reduction statewide, as presented in Table 7 below. 30 Each time SCDOT performs a short-term count, they use a PEEK-ADR 2000 counter and two pneumatic tubes. The counter costs an average of approximately $1000 (depending on features, etc.) and was assumed to have an average lifespan of approximately 200 uses. The tubes used have an approximate cost of $200 per pneumatic tube, with two tubes needed in every count. The average lifespan per tube is estimated at approximately 20 uses (due to tearing, breakage, and wearing out). It was assumed that every short term count requires 3 SCDOT employees for a total of 5 hours at $30/hour, which includes labor, travel, etc. The initial cost to develop the model is not included in this analysis. Additionally, according to the author’s estimates, it will cost approximately $10,000 per year to pay an in-house traffic engineer to maintain the centrality model vs. maintaining the factor method model. Then, the total cost of the centrality based method at each of the four levels of count location reduction was calculated in order to calculate a percent cost savings. Therefore, the cost savings of each reduction level is simply: Eqn. 6 Cost savings = Cost of factor method Cost of centrality method with x% reduction The cost of each method is calculated using the final equation below: Eqn. 5 Total Cost = Cost of traffic counter Cost to run and update the model Cost of tubing Cost of manpower Using this equation, the cost of the factor method was determined to be $5,700,000 annually. 31 TABLE 7 Cost Savings Analysis Percent Reduction of Counts Counts Needed 40% 7,200 50% 6,000 60% 4,800 70% 3,600 Total Savings Total Cost ∗ ∗$ , ∗ ∗$ , ∗ ∗$ , ∗ ∗$ , ∗$ ∗$ ∗ $ , ∗$ ∗$ ∗ $ , ∗$ ∗$ ∗ $ , ∗$ ∗$ ∗ $ , $3,430,000 $2,860,000 $2,290,000 $1,720,000 The costs illustrated in Table 7 (Column 4) are the costs of performing the number of count locations specified at each level of reduction. It is estimated that 12,000 counts are reduced by 4,800, 6,000, 7,200, and 8,400 counts per year for 40%, 50%, 60%, and 70% short-term count reduction scenarios, respectively. Using the Equation 5 shown, the final savings range from $1,720,000 to $3,430,000. Clearly, there is a financial benefit of utilizing this method for SCDOT. The monetary benefits could save DOTs hundreds of thousands of dollars, which could be allocated to other valuable projects, such as roadway and infrastructure maintenance. 32 CHAPTER FIVE CONCLUSION AND RECOMMENDATIONS 5.1 Conclusions Affordably estimating AADT on all of the roadways within a given street network has been a challenge that many transportation agencies face, especially in smaller cities and municipalities where resources are limited. As AADT estimation on local roads is vital, ample amounts of research have been conducted to develop models that can estimate the AADT of every roadway within any jurisdiction. For example, linear regression, travel demand modeling, and Artificial Neural Network models have all been used in an attempt to estimated AADT. The new centrality-based AADT estimation model, utilizing roadway characteristics and new derived origin-destination centrality variables based on the theory of centrality, illustrates a method that is capable of minimizing cost and effort when compared to deploying dozens of short term count locations or using models such as the travel demand model. Not only was a new variable to estimate AADT created, but the model has a lower RMSE than the city’s travel demand model, and can be developed using a GIS software alone. This thesis establishes a means of estimating AADT on every roadway within a given jurisdiction, while reducing the number of coverage counts in Greenville, SC by over 60%. This method has the potential to be used in cities that do not have the time, funding or resources to use coverage counts at many roads throughout their jurisdictions. In addition, this method uses existing and publically available data to quickly and accurately estimate AADT within a reasonable estimation threshold. 33 While this method was successfully applied to Greenville, SC, it has not yet been tested for transferability among other cities within and outside SC. Future research should include a study of transferability. Another limitation of this study is that the “base AADT” counts that were used and compared to this regression model were not perfectly accurate AADT values. At 142 of the 148 locations utilized were calculated counts, the AADT values compared with the ones calculated using this model were also calculated counts, and may not be entirely accurate. The base data was calculated using 24-hour short-term traffic counts and the factor method. 5.2 Recommendations The following recommendations are made based on this research:  The method presented in this study should be examined for other cities before a decision can be made in its broader adoption. This should include cities of various sizes to determine its applicability in various size cities.  This method should be tested at the state level. In addition to its use at the state level, this method can be used at local level as well for low-cost AADT estimation strategy.  This method should be tested against AADT estimations using short-term counts and the factor method at the lowest functional classifications. Currently, there is no short-term count data available for local roads in Greenville, SC.  This method should be tested in an area with a much larger number of permanent count stations for validation. While AADT estimations using short- 34 term counts and the factor method are generally very accurate, they are not perfect data, and this model should be tested against actual ground truth data.  Cost savings estimates could be conducted for a specific area based on regional costs, which can vary based on location-based manpower and equipment costs, in order to determine an exact savings value for their particular agency prior to making a decision. 35 REFERENCES 1. Roess, R. P., E. S. Prassas, and W. R. McShane. Traffic Engineering. Upper Saddle River, NJ, 2011. 2. Zhao, F., and S. Chung. Contributing factors of annual average daily traffic in a Florida county: exploration with geographic information system and regression models. Transp. Res. Rec. 1769, 2001, pp. 113–122. 3. Traffic Forecasting & Analysis. Minnesota Department of Transportation. http://www.dot.state.mn.us/traffic/data/coll-methods.html. Accessed Aug 1, 2016. 4. Guide to LTPP Traffic Data Collection and Processing. McLean, VA: Federal Highway Administration, Office of Infrastructure Research, Development and Technology, Turner-Fairbank Highway Research Center, 2001. http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/ltpp/trfc ol/trfcol.pdf Accessed Jul 2016. 5. Doustmohammadi, M., and M. Anderson. Developing Direct Demand AADT Forecasting Models for Small and Medium Sized Urban Communities. In International Journal of Traffic and Transportation Engineering 5.2, 2016, pp. 27-31. 6. Wang, T., G. Albert, and P. Alluri. Estimating annual average daily traffic for local roads for highway safety analysis. In Transportation Research Record: Journal of the Transportation Research Board, No. 2398, 2013, pp 60-66. 7. Katter, Greg. "INDOT Traffic Data Sources and Using Traffic Count Data System Provided by MS2." (2015). 36 8. Lowry, Michael. Spatial interpolation of traffic counts based on origin– destination centrality. In Journal of Transport Geography 36, 2014, pp. 98-105. 9. United States Census Bureau. When is the census of governments conducted? https://www.census.gov/history/www/faqs/governments_faqs/when_is_the_censu s_of_governments_conducted.html. Accessed on Jul 2016. 10. Sharma, S., P. Lingras, F. Xu, and G. Liu. Neural networks as alternative to traditional factor approach of annual average daily traffic estimation from traffic counts. In Transportation Research Record: Journal of the Transportation Research Board, No. 1660, Transportation Research Board of the National Academies, Washington, D.C., 1999, pp. 24-31. 11. Khan, S. M., Dey, K., and Chowdhury, M., “Real-time Traffic State Estimation with Connected Vehicles,” IEEE Transactions on Intelligent Transportation Systems, doi: 10.1109/TITS.2017.2658664, (2017). 12. Ma, Y., Chowdhury, M., Sadek, A., and Jeihani, M., “Real-Time Highway Traffic Condition Assessment Framework Using Vehicle-Infrastructure Integration (VII) with Artificial Intelligence (AI),” IEEE Transactions on Intelligent Transportation Systems, Vol. 10, No. 4, pp 615-627, (2009). 13. He, Y., Chowdhury, M., Ma, Y., and Pisu, P., “Merging Mobility and Energy Vision with Hybrid Electric Vehicles and Vehicle Infrastructure Integration,” Energy Policy, Modeling Transport (Energy) Demand and Policies, Vol. 41, pp 599-609, (2012). 37 14. Zhang, Yuanyuan, X. Wang, P. Zeng and X. Chen. Centrality characteristics of road network patterns of traffic analysis zones. In Transportation Research 15. Freeman, Linton C. "Centrality in social networks conceptual clarification." Social networks 1.3 (1978): 215-239. 16. Keehan, M., Chowdhury, M., and Dey, K., “AADT Estimation with Regression Using Centrality and Roadway Characteristic Variables,” Accepted for presentation in the 96th Annual Meeting of the Transportation Research Board, Washington, D.C., (2017). 17. City of Greenville, South Carolina. GIS Data. http://www.greenvillesc.gov/364/Access-GIS-Data. Accessed Jul 2016. 18. ITE (Institute of Transportation Engineers), 2012. Trip Generation Manual, 9th Edition, ITE, Washington, DC. 19. U.S. Department of Transportation, Federal Highway Administration, Introduction to Urban Travel Demand Forecasting, Instructor Guide, NHI Course No. 152054, Publication No. FHWA-NHI-08-061, May 2008. 38 APPENDIX A SAMPLE DATA Streets _Shapefile FID 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 OBJECTID 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RECNUM 3 4 5 6 7 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 ST_LABEL RUTHERFORD RD RAYFORD LA N PLEASANTBURG DR TILBURY WY WEDGEWOOD DR BROUGHTON DR INGLEWOOD DR TAMBURLAINE CT WEDGEWOOD DR MEADOW CREST CIR WEDGEWOOD DR SUMMIT DR SUMMIT DR DEARSLEY CT BRENTWOOD DR RUTHERFORD RD GREEN MEADOW LA BRENTWOOD DR BRENTWOOD DR INGLEWOOD DR SUMMIT DR TILBURY WY WEDGEWOOD DR BROUGHTON DR STONE LAKE DR N PLEASANTBURG DR SUMMIT DR GOBLET CT VENNING CT RUTHERFORD RD COOL SPRINGS DR A1 ROADNUM S-23-21 SC-291 S-23-21 SC-291 S-23-21 LADD1 1241 1 2001 1 401 201 13 1 305 1 301 1001 1011 1 31 1221 1 0 13 1 927 51 201 101 1 1901 1043 1 1 1201 1 LADD2 1299 99 2099 11 499 299 99 99 399 99 303 1009 1041 99 41 1239 99 0 29 11 999 99 299 199 99 1999 1051 99 99 1219 99 RADD1 1240 2 2000 2 400 200 12 2 304 2 300 1000 1010 2 30 1220 2 0 12 2 926 50 200 100 2 1900 1042 2 2 1202 2 A2 RADD2 1298 98 2098 12 498 298 98 98 398 98 302 1008 1040 98 40 1238 98 0 28 10 998 98 298 198 98 1998 1050 98 98 1218 98 PREFIX N N NAME RUTHERFORD RAYFORD PLEASANTBURG TILBURY WEDGEWOOD BROUGHTON INGLEWOOD TAMBURLAINE WEDGEWOOD MEADOW CREST WEDGEWOOD SUMMIT SUMMIT DEARSLEY BRENTWOOD RUTHERFORD GREEN MEADOW BRENTWOOD BRENTWOOD INGLEWOOD SUMMIT TILBURY WEDGEWOOD BROUGHTON STONE LAKE PLEASANTBURG SUMMIT GOBLET VENNING RUTHERFORD COOL SPRINGS TYPE RD LA DR WY DR DR DR CT DR CIR DR DR DR CT DR RD LA DR DR DR DR WY DR DR DR DR DR CT CT RD DR SUFFIX A3 ALTNAME RDCLASS 3 1 2 1 1 1 1 1 1 1 1 1 1 1 1 3 1 1 1 1 1 1 1 1 1 2 1 1 1 3 1 MAINTENANC 2 1 2 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 2 1 1 1 2 1 SPEED A4 40 30 40 30 30 30 30 30 25 30 30 35 35 30 30 40 30 30 30 30 35 30 30 25 30 40 35 30 30 40 30 MAJRDS Y N Y N N N N N N N N N N N N Y N N N N N N N N N Y N N N Y N LOW_STREET 1240 1 2000 1 400 200 12 1 304 1 300 1000 1010 1 30 1220 1 0 12 1 926 50 200 100 1 1900 1042 1 1 1201 1 HIGH_STREE 1299 99 2099 12 499 299 99 99 399 99 303 1009 1041 99 41 1239 99 0 29 11 999 99 299 199 99 1999 1051 99 99 1219 99 STREET_ID 5600 2644 2574 5251 3709 446 1629 5252 3709 2117 3709 3105 3105 5563 390 5600 1349 390 390 1629 3105 5251 3709 446 3081 2574 3105 5401 5288 5600 775 SECT_NO 2000000002 0000167600 2000000004 0000167700 0000165800 0000164400 0000164700 0000168000 0000165700 0000167500 0000165600 0000163500 0000163400 0000164200 0000164800 2000000018 0000168100 0000165100 0000164900 0000164600 0000163600 0000167900 0000165500 0000164500 0000168200 2000000028 0000163300 0000164100 0000164300 2000000032 0000167400 A5 EDITORNAME LASTUPDATE CSOURCE LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB LIB 8954 8955 8956 8957 8958 8959 8960 8961 8962 8963 8964 8965 8966 8967 8968 8969 8970 8971 8972 8973 8974 8975 8976 8977 8978 8979 8980 8981 8982 8983 8984 FACILITYID Shape_STLe 527.1766826 1150.473647 614.3874936 415.4401001 186.6661026 735.1952526 308.0473068 235.2168267 263.642934 645.0751654 165.4496045 202.4614411 697.1660385 140.9242893 297.5336242 752.6313822 404.4736069 396.117093 68.30224875 412.1011087 287.5025614 387.9861478 548.1792152 1409.610659 295.3921772 883.2929854 317.2860422 118.7954023 416.1107824 400.3369536 586.6512895 A6