AllChaptersCovered
c c
SOLUTIONS
, th
Traffic Engineering, 5 Edition c c
Roess, R.P., Prassas, E.S., and McShane, W.R.
c c c c c c
SolutionstoHomeworkNo. 2 c c c c
Problem 5‐1 c
A volume of 1,200 veh/h is observed at an intersection approach. Find the peak flow rate
c c c c c c c c c c c c c c c
within the hour for the following peak-hour factors: 1.00, 0.90., 0.80, 0.70. Plot and comment
c c c c c c c c c c c c c c c
on the results.
c c c
Thepeakflow rateofflow iscomputed asv =V/PHF. Thetablebelowsummarizesthe results for
c c c c c c c c c c c c c c c c c c
the information given. A plot follows.
c c c c c c
Evenwiththesamehourlyvolume, a
c c c c c c
small difference in PHF leads to an
c c c c c c c
enormous difference in peak flow
c c c c c
rates. Traffic engineers must be
c c c c c
able to deal with this peaking
c c c c c c
characteristic on a regular basis.
c c c c c
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,Problem 5‐2 c
A traffic stream displays average vehicle headways of 2.4s at 55 mph. Compute the
c c c c c c c c c c c c c
density and rate of flow for this traffic stream.
c c c c c c c c c
A headwaycan beconverted toa flowrateasfollows:
c c c c c c c c c c
v=3600 = 3600 =1,500 veh/hr/ln
c c c c c c c
h 2.4
Knowingbothflowrateand speed(given),thedensitymaynowbecomputed as:
c c c c c c c c c c c c c
D = v = 1500 = 27.3 veh/hr/ln
c c c c c c c
S 55
Problem 5‐3 c
Afreewaydetectorrecordsoccupancyof0.26fora15-minuteperiod. Ifthedetectoris
c c c c c c c c c c c c c c c
3.5 ftlong,andthe average vehicle hasalengthof18 ft.whatisthe densityimpliedby this
c c c c c c c c c c c c c c c c c c c
measurement?
c
Densityisobtainedfromoccupancyasfollows:
c c c c c c
Suchahigh valueisindicativeofhighlycongested conditionswithinaqueue.
c c c c c c c c c c c c
, Problem 5‐4 c
The following traffic count data were taken from a permanent detector location on a major
c c c c c c c c c c c c c c
state highway. From this data, determine (a) the AADT, (b) the ADT for each month. (c) the
c c c c c c c c c c c c c c c c c
AAWT,and(d)theAWTforeachmonth. From thisinformation,whatcan be discerned about
c c c c c c c c c c c c c c c c
the character of the facility and the demand it serves?
c c c c c c c c c c
ThetablebelowillustratesthecomputationofmonthlyADTandAWTvalues.
c c c c c c c c c c c
The AADT is computedasthe total annual volumedivided by365 days,or:
c c c c c c c c c c c c c
AADT= 2,365,000 = 6,479 veh/day
c c c c c
365
The AAWT iscomputedasthe totalweekday volumedivided by260 days,or:
c c c c c c c c c c c c c
AAWT= 2,067,000 = 7,950 veh/day c c c c c
260
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c c
SOLUTIONS
, th
Traffic Engineering, 5 Edition c c
Roess, R.P., Prassas, E.S., and McShane, W.R.
c c c c c c
SolutionstoHomeworkNo. 2 c c c c
Problem 5‐1 c
A volume of 1,200 veh/h is observed at an intersection approach. Find the peak flow rate
c c c c c c c c c c c c c c c
within the hour for the following peak-hour factors: 1.00, 0.90., 0.80, 0.70. Plot and comment
c c c c c c c c c c c c c c c
on the results.
c c c
Thepeakflow rateofflow iscomputed asv =V/PHF. Thetablebelowsummarizesthe results for
c c c c c c c c c c c c c c c c c c
the information given. A plot follows.
c c c c c c
Evenwiththesamehourlyvolume, a
c c c c c c
small difference in PHF leads to an
c c c c c c c
enormous difference in peak flow
c c c c c
rates. Traffic engineers must be
c c c c c
able to deal with this peaking
c c c c c c
characteristic on a regular basis.
c c c c c
@@
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smiciicsiosloaltaiotinon
,Problem 5‐2 c
A traffic stream displays average vehicle headways of 2.4s at 55 mph. Compute the
c c c c c c c c c c c c c
density and rate of flow for this traffic stream.
c c c c c c c c c
A headwaycan beconverted toa flowrateasfollows:
c c c c c c c c c c
v=3600 = 3600 =1,500 veh/hr/ln
c c c c c c c
h 2.4
Knowingbothflowrateand speed(given),thedensitymaynowbecomputed as:
c c c c c c c c c c c c c
D = v = 1500 = 27.3 veh/hr/ln
c c c c c c c
S 55
Problem 5‐3 c
Afreewaydetectorrecordsoccupancyof0.26fora15-minuteperiod. Ifthedetectoris
c c c c c c c c c c c c c c c
3.5 ftlong,andthe average vehicle hasalengthof18 ft.whatisthe densityimpliedby this
c c c c c c c c c c c c c c c c c c c
measurement?
c
Densityisobtainedfromoccupancyasfollows:
c c c c c c
Suchahigh valueisindicativeofhighlycongested conditionswithinaqueue.
c c c c c c c c c c c c
, Problem 5‐4 c
The following traffic count data were taken from a permanent detector location on a major
c c c c c c c c c c c c c c
state highway. From this data, determine (a) the AADT, (b) the ADT for each month. (c) the
c c c c c c c c c c c c c c c c c
AAWT,and(d)theAWTforeachmonth. From thisinformation,whatcan be discerned about
c c c c c c c c c c c c c c c c
the character of the facility and the demand it serves?
c c c c c c c c c c
ThetablebelowillustratesthecomputationofmonthlyADTandAWTvalues.
c c c c c c c c c c c
The AADT is computedasthe total annual volumedivided by365 days,or:
c c c c c c c c c c c c c
AADT= 2,365,000 = 6,479 veh/day
c c c c c
365
The AAWT iscomputedasthe totalweekday volumedivided by260 days,or:
c c c c c c c c c c c c c
AAWT= 2,067,000 = 7,950 veh/day c c c c c
260
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