VDB 3054
VDB3054 HIGHWAY & TRAFFIC ENGINEERING
MAY 2016
TEST #1
1. a. A horizontal curve is to be designed for a section of a highway
having a design speed of 120 kph. If the physical conditions
restrict the radius of the curve to 300 m and coefficient of side
friction is 0.2, determine;
i. Required minimum superelevation of this curve.
V2 V2 V2
R (e f ) e f
127(e f ) 127 R 127 R
100 2
e 0.2 0.18
(127)(300)
[2 marks]
ii. Whether this superelevation obtained is feasible or not?
If not, what change would you suggest to execute this
design? Explain why?
Not possible since maximum e is 0.10. Need to reduce design
speed.
V 127(300)(0.1 0.2) 106.9 Use design speed of 100 kph.
[3 marks]
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VDB 3054
b. A parking lot with 600 bays operates from 8:00 A.M. to 6:00 P.M.
during weekdays. On average, 300 shoppers and 550
commuters park there with average duration of 2 hours and 9
hours, respectively. If the efficiency of the parking lot is 90%
and assuming 3% vacant bay, determine whether the supply met
the demand.
D = 300(2) + 550(9) = 5550 space-hour
S = 600(10)(0.9)(0.97) = 5238 space-hour
Supply does NOT meet the Demand
[5 marks]
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VDB 3054
2. An accident occurred on a freeway during the morning peak hour..
Analysis of the situation revealed a queue profile as shown in FIGURE
Q2(i). Propose measures to be taken in order to make traffic flow
along the freeway smooth and operates at acceptable Level of Service
(LOS). A layout of the freeway where the accident occurred is shown
in FIGURE Q2(ii). Assume the average length of vehicle to be 5 m.
Justify your proposal.
[10 marks]
FIGURE Q2(i)
Interchange A Interchange B
Accident Location
2 km 8 km
FIGURE Q2(ii)
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VDB 3054
Longest Queue = [(1498.33 – 633.33)(5)]/2 = 2163 m
Should take action to avoid queue reaches Interchange A.
Storage between accident site to Interchange A = [(2000)(2)]/5 = 800 veh.
3777.5
Arrival Curve Equation ------ t 48.33t
78.16
Departure Curve Equation (12 < t <31)
633.33
(t 12) 33.33t 400
(31 12)
Queue Length Q 48.33t (33.33t 400)
Q 15t 400 800
t 26.67 minutes
Eastbound traffic should be diverted out at Interchange A the latest
26.67 minutes after the accident
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VDB 3054
3. FIGURE Q3 shows a cross section of an existing divided multilane
highway built on a rolling terrain road reserve with 40 m Right Of Way
(ROW). TABLE Q3 shows data from a survey carried out recently to
assess the Level of Service (LOS) of the highway. Peak hour traffic is
expected to occur between 07:00 and 09:00. Data are for two-way flow
at 55:45 directional split. There are 18 access points/km along the
highway.
Carriageway
Carriageway
Shoulder
Central
Divider
Shoulder
3.0 m 2 @ 3.3 m 10.0 m 2 @ 3.3 m 3.0 m
ROW = 40.0 m
FIGURE Q3
TABLE Q3
Time Car Truck Bus RV
07:00 – 07:15 200 20 30 0
07:15 – 07:30 700 30 30 0
07:30 – 07:45 1000 26 24 0
07:45 – 08:00 1400 36 38 0
08:00 – 08:15 1538 48 46 0
08:15 – 08:30 1266 100 140 0
08:30 – 08:45 1316 36 36 0
08:45 – 09:00 800 34 44 0
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VDB 3054
a. Determine the LOS of the highway if the Base Free Flow Speed
is assumed to be 110 km/h.
Time !5-Min Hourly
07:00 – 07:15 250
07:15 – 07:30 760
07:30 – 07:45 1050
07:45 – 08:00 1474 3534
08:00 – 08:15 1632 4916
08:15 – 08:30 1506 5662
08:30 – 08:45 1388 6000
08:45 – 09:00 878 5404
Peak Hour @ 07:45 - 08:45
Car = 5520
Truck = 220
Bus = 260
PT = (220 + 260)/600 = 0.08
PHF = (6000)/(4)(1632) = 0.92
ET = 2.5 V = 3300 fLW = 3.1 fLC = 0 fA = 12fM = 0
FFS = 110 – 3.1 – 12 = 94.9 95 kph
1
f HV 0.89
1 0.08(2.5 1)
3300
vp 2015
(09.2)(2)(1)(0.89)
With vp = 2015 and FFS = 95, Figure 1 gives LOS E with S = 86
2015
Check for Density D 23.4 OK
86
[10 marks]
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VDB 3054
b. Propose the new cross section of the highway for 10 years
design at LOS D if traffic volume is expected to increase at a
rate of 5% per year for the next 10 years.
v f 3300(1 0.05)10 5375
For LOS D, @ FFS = 90, vp = 1860
@ FFS = 100, vp = 2015
Therefore @ FFS = 95, vp = 1938 (interpolate)
5375
1938
(0.92)( N )(1)(0.89)
5375
N 3.4
(1938)(0.92)(1)(0.89)
4 lanes is required.
Carriageway
Carriageway
Shoulder
Central
Divider
Shoulder
3.0 m 4 @ 3.3 m 7.0 m 4 @ 3.3 m 3.0 m
ROW = 39.40 m
[15 marks]
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VDB 3054
4. The link and node network shown in FIGURE Q4 is representative of
the road and street system. Determine the shortest travel path from
Zone 7 to all other zones and draw the minimum path tree for Zone 7 if
travel times from node to node are as shown.
[5 marks]
1 8 2
1 2 3 4
3 5 6 5
8 9 3
5 6 7 8
2 5 9 8
6 3 7
9 10 11 12
5 6 8 9
8 7 6
13 14 15 16
FIGURE Q4
15 14 8
1 2 3 4
6
17 9 3
5 6 7 8
9 11
15 12
9 10 11 12
23 18 19 20
13 14 15 16
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