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(032) 254-9967 (Cebu)
TRANSPORTATION ENGINEERING
SERVICE RATES AND DEMANDS ON HIGHWAYS
1. A toll bridge carries 6000 veh/day. The current toll is $3.50/vehicle. Studies
have shown that for each increase in toll of 50 cents, the traffic volume will
decrease by 500veh/day. It is desired to increase the toll to a point where revenue
will be maximized.
A. Write the expression for travel demand on the bridge related to toll increase
and current volume.
B. Determine the toll charge to maximum revenues.
C. Determine the traffic in veh/day after toll increase.
D. Determine the total revenue increase with new toll.
2. (MAY 2016) A ramp meter operates during the morning peak period. Ramp
meter cycles vary with time as shown in the table below. The metering scheme
allows one vehicle per cycle to pass the signal. The table below gives the number
of vehicles demanding service on the ramp during the particular time intervals,
the cumulative demand for the ramp for the morning peak and the ramp meter
cycle for each interval.
Daily Expansion Factors:
𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑡𝑜𝑡𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑜𝑟 𝑤𝑒𝑒𝑘
𝐷𝐸𝐹 =
𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑜𝑟 𝑝𝑎𝑟𝑡𝑖𝑐𝑢𝑙𝑎𝑟 𝑑𝑎𝑦
Monthly Expansion Factors:
𝑀𝐸𝐹 =
𝐴𝐴𝐷𝑇
𝐴𝐷𝑇 𝑓𝑜𝑟 𝑝𝑎𝑟𝑡𝑖𝑐𝑢𝑙𝑎𝑟 𝑚𝑜𝑛𝑡ℎ
Accident rate for 100 million vehicle miles of travel (HMVM) for a segment
of a highway.
𝑅=
𝐴(100 000 000)
𝐴𝐷𝑇(𝑁)(365𝐿)
Accident rate per million entering vehicles (MEV) for an intersection
𝑅=
TIME PERIOD
15 min Volume
Cumulative
Meter cycle (s)
Volume
6:30 – 6:45
75
75
6
6:45 – 7:00
100
175
10
7:00 – 7:15
125
300
12
7:15 – 7:30
110
410
12
7:30 – 7:45
80
490
10
7:45 – 8:00
65
555
6
A. What are the service rates for meter cycle 12s? (75)
B. What are the service rates for meter cycle 10s? (90)
C. What are the service rates for meter cycle 6s? (150)
D. Determine the time the queue on the ramp begins and ends. (6:45 – 8:00)
E. Determine the longest queue.
F. Determine the total delay. (3750veh-min)
PEAK HOUR FACTOR
Peak Hour Factor:
𝑃𝐻𝐹 =
For the given data shown:
TIME
8:00 – 8:15
8:15 – 8:30
8:30 – 8:45
8:45 – 9:00
9:00 – 9:15
9:15 – 9:30
A. Peak hour
B. Peak hour volume
C. Peak hour factor
𝑉
4(𝑉15 )
𝐴(1 000 000)
𝐴𝐷𝑇(𝑁)(365)
Severity Ratio
𝑆𝑅 =
𝑓𝑎𝑡𝑎𝑙 + 𝑖𝑛𝑗𝑢𝑟𝑦 𝑎𝑐𝑐𝑖𝑑𝑒𝑛𝑡𝑠
𝑓𝑎𝑡𝑎𝑙 + 𝑖𝑛𝑗𝑢𝑟𝑦 𝑎𝑐𝑐𝑖𝑑𝑒𝑛𝑡𝑠 + 𝑝𝑟𝑜𝑝𝑒𝑟𝑡𝑦 𝑑𝑎𝑚𝑎𝑔𝑒
1. A traffic engineer urgently needs to determine the AADT on a rural primary
road. She collected the data shown below on a Tuesday during the month of
May. Determine the AADT of the road.
Time
7:00 – 8:00
8:00 – 9:00
9:00 – 10:00
10:00 – 11:00
11:00 – 12:00
DEF for Tuesday = 7.727
MEF for May = 1.394
Volume
250
356
251
800
567
HEF
29.00
22.05
18.80
17.10
18.52
2. The projected AADT of a proposed facility is 33,000 veh/day. If the proportion
of AADT in the design hour is 16 percent and the peak-hour directional
distribution is 65:35. Determine the DDHV.
VOLUME
32
37
29
33
37
19
ACCIDENT ANALYSIS
3. Assume that the PHF, fHV, and fp of the proposed facility are 0.91, 0.925, and
1.0, respectively, the maximum service flow rate for the facility to provide a LOS
of 1,500 veh/h/ln. The number of lanes required will be:
4. A vehicle weighing 1300kg travel a distance of 48m before colliding with
another parked vehicles, the weight of which is 1000kg. After collision, if both
vehicles skid through 14m before stopping, determine the initial speed of the
moving vehicle. Assume friction coefficient of 0.62.
5. The number of accidents for 6 years recorded in a certain intersection of a
highway is 4877. If the average daily traffic is 467, what is the accident rate per
million entering vehicles?
AADT – is the average 24 – hour traffic volume at a given location over a full
year.
ADT – is the average 24 – hour traffic volume at a given location for a period of
time less than a year. (e.g. summer, six months, a month, a season)
6. The number of accidents for 5 years recorded in a 10 – mile long highway is
2345. If the average daily traffic is 502, what is the accident rate per hundred
million entering vehicles?
Directional Design Hourly Volume:
7. Data on a traffic accident recorded for the past 5 years on a certain stretch of
a two highway is tabulated as follows. Determine the severity ratio.
𝐷𝐷𝐻𝑉 = 𝑘(𝐷)(𝐴𝐴𝐷𝑇)
k = proportion of AADT occurring at the peak hour
D = peak hour volume proportion in the major direction
Hourly Expansion Factors:
𝑡𝑜𝑡𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑜𝑟 24ℎ𝑟 𝑝𝑒𝑟𝑖𝑜𝑑
𝐻𝐸𝐹 =
𝑣𝑜𝑙𝑢𝑚𝑒 𝑓𝑜𝑟 𝑝𝑎𝑟𝑡𝑖𝑐𝑢𝑙𝑎𝑟 ℎ𝑜𝑢𝑟
YEAR
2001
2002
2003
2004
2005
PROPERTY
DAMAGE
213
178
152
183
245
INJURY
FATAL
67
89
55
74
29
5
4
3
2
1