Final Examination SEMESTER 1, SESSION 2012/2013: Instruction To Candidates
Final Examination SEMESTER 1, SESSION 2012/2013: Instruction To Candidates
Final Examination SEMESTER 1, SESSION 2012/2013: Instruction To Candidates
FINAL EXAMINATION
SEMESTER 1, SESSION 2012/2013
COURSE CODE : SAB3842
PROGRAMME : SAW
DURATION : 2 HOURS
INSTRUCTION TO CANDIDATES:
1. ANSWER QUESTION 1 (COMPULSORY QUESTION) AND ANY THREE
(3) OTHER QUESTIONS
2. WRITE YOUR NAME, SECTION AND LECTURERS NAME ON THE
FRONT PAGE OF EVERY ANSWERS BOOKLET
3. YOU ARE NOT ALLOWED TO REFER TO ANY NOTES
WARNING!
Students caught copying/cheating during the examination will be liable for
disciplinary actions and the faculty may recommend the student to be expelled from
the study.
Q1. (a) Traffic signal control system can be either pre-timed, traffic actuated or
traffic-adjusted.
i) Clearly, distinguished these three types of traffic signal control
systems.
ii) Discuss the advantages and disadvantages of pre-timed and traffic
actuated signal.
(15 marks)
(b) There are several design criteria which govern the various elements in the
design and location of road. List the design criteria and clearly discuss
how they affect the geometric design of the road.
(10 marks)
Q2. (a) Inspection of a freeway data set reveals a maximum free flow speed of 90
km/h, a jam density of 120 vehicles per km per lane, and an observed
maximum flow at site is 2000 vehicles per hour per lane.
i) Derive the linear equation for speed and density for these conditions;
ii) Determine the speed and density at theoretical maximum flow and
the value of the theoretical maximum flow;
iii) Explain why theoretical and observed maximum flow differ, and
discuss factors that influence the maximum flow.
(10 marks)
(b) Derive the equations describing flow versus speed and flow versus
density in question Q2 (a) above.
i) Determine the speed and density for flow of 1200 vehicles per hour
per lane; and
ii) Sketch the flow-speed and flow-density relationships, show the
values on the sketch and describe the traffic flow conditions.
(15 marks)
SAB 3842 3
Q3. (a) Given below is the spot speed for 200 vehicles passing a construction site
on a rural highway.
Tabulate the data in a proper table. Draw the histogram and cumulative
frequency curve of the speed data. Determine and show on the
cumulative frequency curve:
i) Mean speed;
ii) Mode;
iii) Standard deviation;
iv) Median, P15, P50 dan P85.
If the posted speed limit is 50 km/hr, what can be concluded on traffic
and road condition in the study area?
(17 marks)
(b) Given below is data (averaged) from traffic study using Moving
Observer Method on a 3.5km stretch.
Direction Travel No. of vehicles No. of vehicles No. of vehicles
time travelling in that overtook that overtaken by
(min) opposite direction test vehicle test vehicle
Eastbound 2.85 79.5 1.0 1.5
Westbound 3.07 92.2 1.5 0.8
Determine for both directions:
i) Volume for both directions; and
ii) Average journey speed for the traffic stream for both directions.
(8 marks)
SAB 3842 4
Q5. a) One of the UTM Traffic Engineering student is trying to test the braking
ability of his car found that he needed 5.64 m more to stop his car when
driving downhill on a road of 5% grade than when driving downhill at
the same speed on a 3% grade. If the coefficient of friction, f is 0.35,
determine:
i) the speed at which the student conducted his test;
ii) the distance travelled before the car comes to a stop on the 7%
uphill grade if the student is travelling at the same speed, given
his perception-reaction time is 2.5 seconds; and
iii) discuss factors that affects braking distance.
(15 marks)
EQUATIONS
The symbols indicate parameters usually used.
R.g.e
X Y1 Y2 AB V 3 1 2
Length of transition curve, LP
Q AB AB V
t A tW c.R
Y1 Y2 AB
t AB tW
Q AB AS 2
L
2 h1 h2 2
u
u uf f k
k
j L 2S
2 h1 h2 2
A
kj 2
q kj u u
uf SR
b
1.524
1
uf 2 r
q uf k k
kj
b = 1800 for single lane
b = 3000 for two lanes
Vi
f V
i i
f
I = R + a , S = 525W
i
f iVi 2 f iVi V W ' L'
2
qi
SD a yi
fi f 2A V Si
i
n n n
Perception Distance 0.28Vt Y yi L Ri li
i 1 i 1 i 1
V 2 u2 1.5L 5
Braking distance Optimum Cycle Time, CO
254 f G 1Y
V2
R
127e f Effective green, g i
yi
CO L
Y
LP
2 P , P 57.3 Actual green time Gi = gi + l + R
2R
Controller green time Ki = gi + l a
2
Length of circular segment, LB R
360
SAB 3842 6