Concept explainers
The flow, the average speed and the density of the traffic in the given lane.
Answer to Problem 1P
The traffic flow is
Explanation of Solution
Given:
The average headway is
The average spacing of passing is
Formula Used:
Write the expression for the traffic flow.
Here,
Write the expression for the average traffic speed.
Here,
Write the expression for the density.
Here,
Calculation:
Substitute
Substitute
Substitute
Conclusion:
Thus, the traffic flow is
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Chapter 5 Solutions
PRIN.OF HIGHWAY ENGINEERING&TRAFFIC ANA.
- The primary elements of traffic flow are flow, density, and speed. Discuss with illustration the relationships between the three elements of a traffic flow.arrow_forwardExample -2 A section of highway having a length 60 m. The observed data are 6 vehicles cross over it in a period of 148 sec., for the following duration: 2.4, 2.8, 3.0, 2.1, 2.2, and 3.5 sec. Estimate the values of the flow rate, density, space-mean speed, time- mean speed, average gap, and average clearance. If the length of vehicles are 6, 5.4, 6.6, 4.8, 7.5, and 6 m respectively? Solution:arrow_forwardassume you are observing traffic in a single lane of a highway at a specific location. You measure the average headway and average spacing of passing vehicles as 4.8 seconds and 150 ft, respectively. Calculate the flow (veh/hr) Choices: 500, 750, 208, 1250arrow_forward
- 1. Compute the rate of flow in vehicles per hour (two-decimal places) if the space mean speed is 30 mph and the density is 14 vehicles per km. 2. The spacing of the cars moving along the same lane of an expressway is 40 m center to center. If the average velocity of the car is 60 kph, determine the volume of traffic in veh/hr. 3. In a given instant, there were 2400 vehicles counted at a specific point along the portion of the TPLEX. The highway was designed to have a capacity of 3000 veh/hr with a free-flow speed of 60 kph. Compute the maximum value of the jam density in veh/km that could possibly occur during heavy traffic assuming linear speed-density relationship appliesarrow_forward9. 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? a) 60 kph b) 45 kph c) 55kph d) 75kph 10. In Problem 9, what is the density of vehicles at maximum flow? a) 1/3 jam density b) 1/4 jam density c) 1/2 jam density d) none of thesearrow_forwardTraffic is observed at a single lane of a highway at a specific location. The average headway and average spacing of passing vehicles are measured as 3.5 seconds and 192 ft., respectively. Calculate the average speed (mph), flow (veh/hour), and density (veh/mile) of the traffic stream in this lanearrow_forward
- A section of highway having a length 60 m. The observed data are 6 vehicles cross over it in a period of 148 sec., for the following duration: 2.4, 2.8, 3.0, 2.1, 2.2, and 3.5 sec. Estimate the values of the flow rate, density, space-mean speed, time-mean speed, average gap, and average clearance. If the length of vehicles are 6, 5.4, 6.6, 4.8, 7.5, and 6 m respectively?arrow_forwardSix vehicles are observed in a 200 m section of a highway. If the average time headway is 4 sec., determine the density of flow (veh/km), flow of traffic (veh/hr) and space mean speed (kph).arrow_forwardMeasurements from a single-lane roadway reveal that the average spacing and headway between passing vehicles are 200 ft and 2.4 seconds, respectively. What is the flow [veh/hr], density [veh/mi] and average speed [mi/hr] of traffic on this roadway?arrow_forward
- Assume that the speed-density function of a section of highway follows Greenshield's Model. The free-flow speed is 75 mph and the jam density is 176 veh mi lane a. Derive V as a function of S. b. In 15 minutes, you have counted that V=150 veh 15 minute lane Estimate the two possible speeds S (in mph) during this 15 minute period.arrow_forward1. The rate flow at a point in the highway is 1200 vehicles/hour. Find the space mean speed in mph if the density of traffic is 25 vehicles per mile 2. Assume you are observing traffic in a single lane of McArthur Highway at a specific location. You measure the average headway and average spacing of the vehicles as 3.2sec. and 50 m. respectively. Determine the traffic speed in kilometer/hourarrow_forwardF] Vehicles travel at constant speeds on a one-lane one-way street between sections X and Y. An observer located at point X observes the four vehicles passing point X during a period of 10 seconds. The speeds of the vehicles are measured as 45, 45, 40, and 30mph, respectively. Calculate the average flow, density, time mean speed, and space mean speed.arrow_forward
- Traffic and Highway EngineeringCivil EngineeringISBN:9781305156241Author:Garber, Nicholas J.Publisher:Cengage Learning