Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Chapter 6, Problem 9P
To determine
Optimum speed and optimum density if the traffic stream is modeled using Greenberg model and free flow speed, optimum speed and optimum density if the traffic stream is modeled using Greenshields model.
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Given a freeway flow study at a certain highway. The speed- density relationship is described in the givenequation or relationship:
V s = 58- 0.40k
Determine the following:a. Free-flow speed and jam densityb. Derive the equation describing flow and speed.c. Derive the equation describing flow and density.d. Determine the capacity of highway
The lane of a 2-lane one way carriageway is closed for repairs. The maximum mean free speed under conditions of low flow in the 2-lane portion is 65km/hr. Under conditions of low flow, observations show that the maximum mean free speed in the bottleneck is also 65km/hr. The average space headway when vehicles are stationary is 12.5m. The volume of traffic on the 2-lane road is 1800 veh/hr. Assuming that the speed-concentration relation is linear, find
The mean speed of traffic through the bottleneck caused by the closure of one lane;
The mean speed of traffic in the congested conditions immediately on the approach to the bottleneck
The mean speed of traffic on the carriageway clear of the influence of the bottleneck
The rate at which the queue of the congested traffic enter
Given a freeway flow study at a certain highway. The speed- density relationship is described in thegiven equation or relationship:V s = 60- 0.48kDetermine the following:a. Free-flow speed and jam densityb. Derive the equation describing flow and speed.c. Derive the equation describing flow and density.d. Determine the capacity of highway
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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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.Similar questions
- A freeway traffic stream was observed to have a density of 22.0 veh/mi/ln when the mean speed was 55.0 mi/h. On another occasion at the same location, the jam density was found to be 132 veh/mi/ln. Assume Greenshields' model of traffic flow applies. The optimum speed (in mi/h) is: a) 22.0 b) 33.0 c) 55.0 d) 66.0 e) None of he abovearrow_forwardUsing Greenshields' model, for a highway with a mean free flow speed of 76 mi/h and jam density of 128 veh/mi, determine the density (in veh/mi) when the mean speed is observed to be 58 mi/h:arrow_forwardA freeway traffic stream was observed to have a density of 22.0 veh/mi/ln when the mean speed was 55.0 mi/h. On another occasion at the same location, the jam density was found to be 132 veh/mi/ln. Assume Greenshields' model of traffic flow applies. The flow rate (in veh/h/ln) at the time when the mean speed was 55.0 mi/h is: 990 1210 1540 2178 None of the abovearrow_forward
- A section on a highway is known to have a speed at maximum flow to be 30kph and a capacity of 3300veh/hr. In a given hour, 2100 vehicles were counted at a specified point along this highway section. Determine the following using if the relationship of speed and density is logarithmic. Determine the jam density in veh/km.arrow_forwardLinear regression analysis was performed on a set of traffic data using speed and density measurements from a highway segment. The following equation was developed. ?? = 57.5 − 0.457?? Use this equation, as well as the fundamental relationship equations to answer the following questions. What is the free-flow speed for this data? What is the jam density of this data? What is the maximum flow of this highway segment? What is the mean speed at this maximum flow?arrow_forwardDetermine i) capacity, ii) jam density, iii) speed and iv) density at capacity of a traffic stream if the speed density relationship follows relation v = 17.2 ln(228/k), if v is space mean speed in km/hr and k is the density at veh/km.arrow_forward
- A segment of a highway was designed for a free flow speed of 90 mph. At the time of observation along the segment, it was recorded that same segment was at its maximum flow. What is the average speed of vehicles at this instant?arrow_forwardConsider only a single lane of a highway. Based on extensive data from an urban freeway it is assumed thatfree-flow speeds (i.e., there are no jams) can best be represented by a Normal distribution with mean andstandard deviation 119 km/h and 13.1 km/h, respectively.1. What is the probability that the speed of a randomly selected vehicle is between 100 and 120 km/h?2. What is the expected number of vehicles between two vehicles that exceed the posted speed limit of100 Km/h? You can use the Z table for calculating the final answer. You can also write your final answer in form ofR functions or as PDF/CDF of statistical distributions with correct arguments.arrow_forwardA section of highway has a speed-flow relationship of the form q = a*u*u + b*u (a and b are coefficients to be determined). It is known that at capacity (which is 3100 veh/h) the space-mean speed of traffic is 35 km/h. Determine the speed when the flow is 1500 veh/h and the free-flow speed.arrow_forward
- Based on a linear speed-density model, with a jam density of 120 vpmpl and a free flow speed of 60 mph, estimate the density (vpmpl) if the speed is 30 mph.arrow_forwardStudies have shown that the traffic flow on a single-lane approach to a signalized intersection can be described by the Greenshields model. If the jam density on the approach is 130 veh/mi, determine the velocity of the stopping wave when the approach signal changes to red if the density on the approach is 45 veh/mi and the space mean speed is 40 mi/h. At the end of the red interval, what length of the approach upstream from the stop line will vehicles be affected if the red interval is 35 sec?arrow_forward1. There are 3 vehicles observed in a 100 m section of McArthur highway. If the average time headway is 4 sec., compute the space mean speed of the vehicles in kph. 2. Three cars travel over a 60 m. section of highway at constant speeds of 19, 20 and 25 m/s. Compute the time mean speed for this condition in m/s (two decimal places 3. If the density of traffic in Aurora Blvd. is 25 veh/km and the average headway is 4 sec., compute the space mean speed in kpharrow_forward
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