The speed-density relationship in a mid-block section of a highway follows the Greenshield's model. If the freeflow speed is V, and the jam density is k, the maximum flow observed on this section is(b) v,k,(d) V.kv,k(c) Vik

Given data: The free flow speed is Vf The jam density is kj

The speed-density relationship in a mid-block section of a highway follows the Greenshield's model. If the flow speed is V, and the jam density is k, the maximum flow observed on this section is (a) Vik (b) v k (d)

The speed-density relationship in a mid-block section of a highway follows the Greenshield's model. If the flow speed is V, and the jam density is k, the maximum flow observed on this section is (a) Vik (b) v k (d)

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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Highway Engineering
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 50 mph.
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For the case of a bottleneck in a highway where two lanes in one direction must narrow down to one lane, if the flow in vehicles/hour is greater than the capacity of the bottleneck but less than the capacity of the unrestricted two lanes of travel, a queue will form, and its length will increase over time. A) True B) False
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2. The upstream traffic flow on a road with two lanes in the relevant direction is qı= 1800 veh/hr with freeflow speed of vi=90 km/hr. As the result of a crash, one lane is blocked and flow is reduced to q2 = 900 veh/hr. The density in the queue is k2 = 70 veh/km. The value of time is GHC 10/hour/vehicle. Find: (a) The shockwave speed (vw) (b) The number of vehicles that will be in the queue if the traffic situation continues for 1 hour before the lane is cleared. (c) The cost of the crash to society in terms of delay (hint: use travel time in excess of freeflow travel time to determine this) (d) The amount to be paid to a freeway service patrol (tow truck service) if it can clear the crash in 30 minutes (e) The amount to be paid to a freeway service patrol if a variable message sign placed 2 km upstream of the crash site instantly advises travelers about a diversion to a frontage road 1 km upstream of the crash site
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