Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Chapter 6, Problem 24P
To determine
The resultant effect of a sudden reduction of the capacity on a highway due to a bottleneck using appropriate diagrams.
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The relationship between flow and density on a four-lane highway (two lanes per direction) is
known to follow GreenShiled's model, with a free flow speed of 100 km/h and a jam density of
80 veh/km/lane. One of the two lanes of the EB direction will be closed for an entire month for
maintenance. The traffic demand for the highway on a typical weekday is shown in the table below.
a) What is the maximum length of the queue upstream of the bottleneck during both the
morning and afternoon peak hours?
b) At what time will the morning and afternoon queues be dissipated?
c) Draw the shock wave diagram (for the entire day) showing shock wave speeds, critical
times, and distances.
Time
7:00 AM - 9:00 AM
9:00 AM 3:00 PM
3:00 PM 7:00 PM
7:00 PM–11:00 PM
11:00 PM 7:00 AM
Average Demand (vph)
3000
1500
3200
1200
400
A two-lane, one-way, rural freeway segment is being designed to service a demand volume of 4,000 vehicles per hour. The PHF is expected to be 0.95. If the combination of trucks, buses, and recreational vehicles is represented by a heavy vehicle adjustment of 0.85, what is the flow rate (pcphpl)? Provide your answer to the nearest integer.
Traffic flow on a three-lane (one direction) freeway can be described by the Greenshields model. One lane of the three lanes on a section of this freeway will have to be closed
to undertake an emergency bridge repair that is expected to take 2 hours. It is estimated that the capacity at the work zone will be reduced by 35 percent of that of the section
just upstream of the work zone. The mean free flow speed of the highway is 50 mi/h and the jam density is 115 veh/mi/In. If it is estimated that the demand flow on the
highway during the emergency repairs is 85 percent of the capacity, using the deterministic approach, determine the following.
(a) the maximum queue length (in veh) that will be formed
Your response differs from the correct answer by more than 10%. Double check your calculations. veh
(b) the total delay (in h)
h
(c) the number of vehicles that will be affected by the incident
veh
(d) the average individual delay (in min)
min
Chapter 6 Solutions
Traffic and Highway Engineering
Ch. 6 - Prob. 1PCh. 6 - Prob. 2PCh. 6 - Prob. 3PCh. 6 - Prob. 4PCh. 6 - Prob. 5PCh. 6 - Prob. 6PCh. 6 - Prob. 7PCh. 6 - Prob. 8PCh. 6 - Prob. 9PCh. 6 - Prob. 10P
Ch. 6 - Prob. 11PCh. 6 - Prob. 12PCh. 6 - Prob. 13PCh. 6 - Prob. 14PCh. 6 - Prob. 15PCh. 6 - Prob. 16PCh. 6 - Prob. 17PCh. 6 - Prob. 18PCh. 6 - Prob. 19PCh. 6 - Prob. 20PCh. 6 - Prob. 21PCh. 6 - Prob. 22PCh. 6 - Prob. 23PCh. 6 - Prob. 24PCh. 6 - Prob. 25PCh. 6 - The arrival times of vehicles at the ticket gate...Ch. 6 - Prob. 27P
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- Oasis Freeway is a four lane road located in the Metro where trucks, buses, and rvs can be found aside from passenger cars. At some point further along the roadway there is a 5.5% upgrade that is 1.3 km long. If the traffic stream has 25% large trucks and buses and 5% recreational vehicles, what is the heavy vehicle adjustment factor?arrow_forwardTwo lanes of the four lanes on a highway section have to be closed to undertake an emergency bridge repair that is expected to take 120minutes hr. The highway's mean free speed is 90km/h, and the jam density is 140 veh/km/ln. If it is estimated that the demand flow on the highway during the emergency repairs is 80% of the capacity (max flow), using the deterministic approach, determine: 1. The maximum queue length that will be formed.2. The number of vehicles that will be affected by the incident.3. The average individual delay.arrow_forwardTraffic flow on a section of a 2 lane road can be described by the Greenshields model with a mean free speed of 80 kph and jam density of 95 veh/km/lane. At the time when a flow was 90% of the capacity of the road, a large dump truck loaded with heavy industrial machinery from an adjacent construction site joins the traffic stream and travels at a speed of 20kph for a length of 6.60 km along the upgrade before turning off onto a dump site. Due to the relatively high flow in the opposite direction, it is impossible for any car to pass the truck. Find how many vehicles will be in the platoon behind the truck by the time the truck leaves the road. Find also the shockwave speed created by the truck.arrow_forward
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