Traffic And Highway Engineering
5th Edition
ISBN: 9781337631020
Author: Garber, Nicholas J.
Publisher: Cengage,
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Question
Chapter 9, Problem 1P
To determine
The traffic characteristics with each of the levels of service for primary freeway sections.
Expert Solution & Answer
Explanation of Solution
Introduction:
Level of service is a qualitative method which is used to describe the operating conditions of a given freeway segment. This method uses density as the variable and alphabetic grading system raging between A to F.
There is 6 basic level of service, which is described below.
- Level of service A.
- Level of service B.
- Level of service C.
- Level of service D.
- Level of service E.
- Level of service F There is a complete blockage in the traffic flow.
The vehicles move freely within the traffic stream without any interruption. Effect of incidents or point breakdown is easily absorbed.
Traffic moves under reasonably free flow condition with minimum restrictions. Effect of incidents or point breakdown is easily absorbed.
The speed of the vehicles is almost equal to free flow speed, but the free flow of the vehicles is constrained. The driver has to be cautious while shifting lanes. Small incidents are absorbed but large incidents direct to queuing of vehicles.
In the traffic stream, the free movement of vehicles is very much restricted, and there is no level of comfort. Even a minor incident leads to queuing of vehicles.
There are no good gaps between the vehicles, and the operations are unbalanced. The entry of vehicles from ramps or sub-lane leads to a blockage in the traffic flow.
Conclusion:
There are six levels of service which are represented alphabetically from A to F. Level of service A being the ideal for driving with decreasing free flow and level of service F being congested.
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Briefly describe the traffic characteristics associated with each of the levels of service for basic freeway sections.
An existing urban freeway with 4 lanes in each direction has the following characteristics: peak hour volume (in the peak direction) of 7070 veh/h, trucks are 10% of peak hour volume, lane width = 11 ft, shoulder-width = 6 ft no interchanges or ramps along this section and the terrain type is rolling.
g) Determine Vp
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Chapter 9 Solutions
Traffic And Highway Engineering
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