Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Chapter 6, Problem 12P
To determine
Capacity of the highway from the given data using regression analysis, and the flow conditions for the given model to be valid.
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The table below shows data on speed and corresponding densities on a section of a collector road. It can be assumed that the traffic flow characteristics can be described by the greenberge model, develop an appropriate relationship between flow and density. Also deyerdete the capacity of this section of the road
Speed kph
density veh/km
60
20
46
32
40.8
38
39.3
40
35.7
45
32.6
50
30.8
53
28.4
57
24.7
65
18.5
80
A data collection study found a linear speed - density relationship for a highway as follows u/65 +k/120 =1
1-Write down the speed - density ( given ) , flow - density and flow - speed models , and plot their relationships
2-raffic study has shown that the time headways between successive vehicles on this highway are exponentially distributed and that 30% of the headways between vehicles are 4 seconds or greater. Apply the traffic models derived in the question a), compute speeds and densities corresponding to this flow.
The data shown below were obtained by time-lapse photography on a highway. Use regression analysis to fit these data to the Greenshields model and determine
The mean free speed
The jam density
The capacity
The speed at maximum flow
Speed(mi/h)
Density (veh/mi)
14.2
85
24.1
70
30.3
55
40.1
41
50.6
20
55
15
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
- By employing linear regression on the field data for speed and density in the table below, find the macroscopic flow equation assuming the traffic flow follows to greenshield model. Calculate the free mean speed, jam density, and maximum flow. Speed (km/h) Density (veh/km) 53.2 20 48.1 27 44.8 35 40.1 44 37.3 52 35.2 58 34.1 60 27.2 64 20.4 70 17.5 75 14.6 82 13.1 90 11.2 100 8.0 115arrow_forward1.) From the traffic studies performed along a street shows the distances each vehicle traveled every 3 seconds on a portion of the highway. Vehicle Distance, m 1 82.6 2 89.9 3 84.6 4 82 a.compute the space mean speed of the traffic, in kph.b.compute the flow of traffic.c.compute the density of traffic.arrow_forwardA Greenberg’s model was developed based on data collected from a roadway. The following values are given: Dj = 130 veh/mi; D = 30 veh/mi when S = 30 mi/h. Find the maximum flow for this traffic stream (vmax)arrow_forward
- 1. Data on density and speed were obtained from a four-lane, two-way rural highway (in one direction only): Fitting the recorded data using linear regression, determine: a.the speed-density relationshipb.the correlation coefficientc.The capacity of the road.arrow_forwardThe traffic volume for a section of a highway can be estimated using the following equation: q = 15.1k[ln (195) - In(k)] Where q is the traffic flow measured in veh/hr and k is the traffic density measured in veh/mi. Based on the provided information, estimate the following (Show all your calculation steps): Maximum flow a. b. Jam density C. Maximum densityarrow_forwardThe data shown below were obtained by time-lapse photography on a highway. Use regression analysis to fit these data to the Greenshields model and determine the following. Speed (mi/h) Density (veh/mi) 16.7 84 25.7 69 35.2 54 43.1 40 54.4 19 56.1 14 (a) the mean free speed (in mi/h) mi/h (b) the jam density (in veh/mi) veh/mi (c) the capacity (in veh/h) veh/h (d) the speed at maximum flow (in mi/h) mi/harrow_forward
- Suppose you are noticing traffic in a single lane of an expressway at a particular area. The average headway is quantified as 4.2 seconds. The average spacing of successive vehicles is found as 38 meters. According to the findings, compute the average speed, flow, and density of this stream on the lane.arrow_forwardThe arrival of vehicles at a specified roadway location is Poisson distributed. The flow count shows 540 veh/hr at this roadway location. - What is the probability that headway between successive vehicles will be less than 6 seconds? - What is the probability that headway between successive vehicles will be greater than than 12 seconds? - What is the probability that headway between successive vehicles will be between 6 and 12 seconds? - Draw the probability density function of the exponential distribution and show the key items in the graph. - Draw the cumulative distribution of the exponential distribution and show the key items in the graph.arrow_forward- From the traffic studies performed along a street shows the distances each vehicle traveled every 3 seconds on a portion of the highway. Vehicle Distance, m 1 82.6 2 89.9 3 84.6 4 82 a.computethe space mean speed of the traffic, in kph.b.computethe flow of traffic.c.computethe density of traffic.arrow_forward
- Consider 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_forwardTo determine the ADT on the road, the data was collected as shown below on a Tuesday during the following. Consider If the traffic is expected to be 180% from the current traffic up to May 2030, Table 1: Traffic volume at specific time 7:00–8:00 a.m. 8:00 –9:00 a.m 9:00–10:00a.m 10:00–11:00 .m 11:00 –12 noon 150 120 130 50 20arrow_forwardConsidering linear relationship between density and speed; you are required to estimate the corresponding flow and speed values to densities of 10, 20, 30, 40, 50, 60 and 70 vehicle/km if the free flow speed is 90 km/hr and at critical situation, it is founded that there are 110 vehicles on a section of road with length 2.0 km. using the estimated values, draw a sketch showing the speed flow - density relationships?arrow_forward
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