Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Chapter 5, Problem 14P
To determine
The relative severity index at an unsignalized intersection.
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Q 04: Discuss Road accident data base and also suggest what remedial measures are required to reduce the causes of accidents.
The state transportation agency has established crash
reduction factors shown in the table. An intersection has
been identified as having an abnormally high left turn crash
rate (17, 20, and 18 crashes in the last three years),
attributed to excessive speeds and the absence of an
exclusive left-turn phase. The ADT of the intersection for
the last three years is 8,400, and the ADT for after
implementation is 9,500. Determine (a) the appropriate
countermeasures and (b) the expected reduction in crashes
if the countermeasures are implemented. .
Countermeasure
Crash Reduction Factor
Retime Signals
0.10
Provide left-turn signal phase 0.30
Reduce speed limit on
approaches
0.35
Provide turning guide lines
0.05
Prohibit left turns
0.75
A state transportation agency want to evaluate engineering countermeasures applied to a two-lane,two-way rural highway segment.This 4 miles segment has been identified as having 14,19,and 23 total crashes in the last three years,before the implementation of the countermeasures.The AADT at the segment for last three years is 5630 vehicles per day and the AADT for after implementation is 6240 vehicles per day.Compute the expected average crash frequency for the after period, assuming the treatment was not implemented.The segment has the same conditions as the base conditions established for SPF.
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- need help.arrow_forwardMatch the following facility with the LOS criteria used to evaluate the performance on the facility Freeway basic segment A. Density Multilane highway automobiles B. Bike LOS score C. Percent time spent following Freeway weaving segment D. Number of crashes Signalized Intersection Bicycles on multilane highways E. Average speed F. Average delay per vehiclearrow_forwardThree designs have been proposed to improve traffic flow at a major intersection in a heavily traveled suburban area. The first alternative involves improved traffic signaling. The second alternative includes traffic-signal improvements and intersection widening for exclusive left turns. The third alternative includes extensive reconstruction, including a grade separation structure. The construction costs, as well as annual maintenance and user costs, are listed in the following table for each alternative. Determine which alternative is preferred based on economic criteria if the analysis period is 20 years and the annual interest rate is 15%. Show that the result is the same using the present worth, equivalent annual cost, benefit–cost ratio, and rate-of-return methods.arrow_forward
- Three designs have been proposed to improve traffic flow at a major intersection in a heavily traveled suburban area. The first alternative involves improved traffic signaling. The second alternative includes traffic-signal improvements and intersection widening for exclusive left turns. The third alternative includes extensive reconstruction, including a grade separation structure. The construction costs, as well as annual maintenance and user costs, are listed in the following table for each alternative. Determine which alternative is preferred based on economic criteria if the analysis period is 20 years and the annual interest rate is 15%. Show that the result is the same using the present worth, equivalent annual cost, benefit–cost ratio, and rate-of-return methods. Alternatives Capital Cost ($) Annual Maintence ($) Annual User Cost ($) Salvage Value ($) Present Condition 0 15,000 600,000 0 Traffic Signal 340,000 10,000 450,000 25,000 Intersection Widening 850,000 5,000…arrow_forwardNeed type answer a. A section of road has 55 accidents recorded in three years. For the same period, the estimated vehicle travel on the section was 23 mvk. Considering only those sections having the same characteristics as the section under study, the mean rate is 80 accidents per 100 mvk. Is the section hazardous with 90 percent level of confidence? b. Based on the graph of the accidents time per day on ‘explain’, what time makes up the most number of accidents? Discuss and explain why the frequency of accident is high.arrow_forwardA proposed improvement will widen a two-lane rural highway from 9-ft-wide (per lane) to 11-ft-wide (per lane) if the highway has an AADT of 2100 veh/day. If there are an average of 25 crashes per year on the segment proposed for improvement, and 67% of the crashes are of the type targeted by the improvement, estimate the expected number of crashes (per year) after the improvement is constructed.arrow_forward
- Problem 2 The table shows reported accidents for a 10-mile highway section of the Diosdado Macapagal Boulevard. Property Damage Year 2000 2001 2002 2003 2004 Average Daily Traffic 20,500 22,000 23,500 24,000 25,500 165 150 170 170 160 Injury Accidents 40 45 50 45 60 a) Compute the severity ratio. b) Compute the accident rate for injury accidents in HMVM. c) Compute the accident rate in HMVM. Fatal Accidents 5 5 10 16 19arrow_forwardTransportation Engineeringarrow_forwardWhat are the reasons traffic impact assessment is conducted? Elaborate.arrow_forward
- 1. With the new highway interchange at a dangerous street intersection, police records indicate an average of 5 accidents per month. The Department of Traffic Safety wants to investigate the probability of the following occurring in any month:a) No more than 4 accidents.c) At least 2 accidents.b) A single accident.d) At most 2 accidents in 15 days.arrow_forwardFind the crash frequency and crash rate of the following: Road Segment A: A three-mile section of road that has had four crashes over five years and has a traffic volume of 5,500 vehicles per day. Road Segment B: A three-mile section of road that has had 10 crashes over five years and has a traffic volume of 18,000 vehicles per day.arrow_forwardThe accident rate for 100 million vehicle miles of travel is 9.8. The length of the road is 15 mileswith an ADT of 67,000. Determine the estimated yearly reduction in total crashes if the crashreduction factor is one third.arrow_forward
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