Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Question
Chapter 5, Problem 16P
To determine
Whether the distribution of crashes at unsignalized rural intersections is the same for all AADT levels by using Kruskal-Wallis H test.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
22. An intersection had 25 reported traffic crashes during the months of January through
September. The AADT for the intersection is shown. What is the crash rate per million entering
vehicles
2000
8000
4000
For a specific rural road segment in northeast Colorado, the total number of crashes as well as the number of fatal crashes have been recorded. Using the data provided with a traffic analysis within two standard deviations (or 95% confidence interval), determine if this site should be flagged for further study.
Data:
Length of road segment = 2 mi.
AADT = 11,350 veh/day
Total number of injury crashes for past 5 years = 55
Total number of fatal crashes for past 5 years = 5
Total number of property-only crashes for past 5 years = 100
Average number of statewide injury crashes for rural roads over past 5 years = 1.30 per 106 VMT
Average number of statewide fatal crashes for rural roads over past 5 years = 0.02 per 106 VMT
Average number of statewide property only crashes for rural roads over past 5 years = .033 per 106 VMT
Weighted average crash rate of injury crashes for rural Colorado roads = 3
Weighted average crash rate of fatal crashes for rural Colorado roads = 8
Weighted…
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
Chapter 5 Solutions
Traffic and Highway Engineering
Knowledge Booster
Similar questions
- Studies were conducted at two sits on rural roads with similar characteristics. The first site was 7.5 miles in length with an Annual Average Daily Traffic (AADT) of 7,400. Over the year-long study period, 42 crashes occurred on this portion of roadway, 5 of them resulting in fatalities. The second site was a 14-mile section with an AADT of 4,700. There were 67 crashes in this section with 5 fatalities. Determine the appropriate crash rates for both locations, and discuss the implications.arrow_forwardA 15 mile section of Kapayapaan Road had the following reported accidents for 6 years from 1992. It is required to compute the accident rates of all accidentsarrow_forwardDetermine the crash modification factor that can be used to estimate the change in frequency of the crash type targeted by a proposed improvement that 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 1500 veh/day.arrow_forward
- The number of crashes involving trucks (“truck crashes”) has continuously increased as thenumber of truck increases. To analyze the association of truck crash rates with the number oflanes, truck crash rates were compared between two-lane and multi-lane highways as shown inthe table below. Is the standard deviation of truck crash rates significantly higher for two-lanehighways than multi-lane highways?Note: Final answer should be either “The standard deviation of truck crash rates is significantlyhigher for two-lane than multi-lane highways” or “The standard deviation of truck crash rates isnot significantly higher for two-lane than multi-lane highways”.Truck crash rates (crashes/million vehicle-km)Site No. Two-lane highways Multi-lane highways12345670.2560.3420.8421.0210.3610.2620.8610.1880.3120.4210.2850.2250.183arrow_forward5. The table below gives data on accepted and rejected gaps of vehicles on the minor road of an unsignalized intersection. If the arrival of major road vehicles can be described by the Poisson distribution, and the peak hour volume is 1100 veh/h, determine the expected number of accepted gaps that will be available for minor road vehicles during the peak hour. Number of Rejected Gaps > t Number of Accepted Gaps >t Gap (t) (s) 1.5 92 3 2.5 52 18 3.5 30 35 4.5 10 62 5.5 2 100arrow_forwardGiven Length of segment highway = 0.3 miles AADT = 1600 vehicles / day Test factor = 1.96 for 95% confidence level For a 4 year period: Average crash rate per million entering vehicles. Property damage = 250 Fatal (Death) = 120 Calculate the critical crash rate. 730 crashes O 973 crashes O 937 crashes O 708 crahsedarrow_forward
- 7. The following are the tabulation of the coverage count of the average daily traffic on a monthly and weekly basis made with automatic traffic counts on a highway. Use the tables to calculate;(a) the ADT for February and October based on 2 days counts: (i) on Tuesday in February the daily counts were 250 vehicles and (ii) on Friday in October, the daily traffic volume was 300 vehicles. (b) the AADT if the flows counted on Friday, Saturday and Sunday in July were 8000, 6000 and 5000 vehicles on a 16 hourly count basis.(c) the seven day 16 hourly flow in September.arrow_forwardThe table below gives data on accepted and rejected gaps of vehicles on the minor road of an unsignalized intersection. If the arrival of major road vehicles can be described by the Poisson distribution, and the peak hour volume is 1100 veh/h, deter- mine the expected number of accepted gaps that will be available for minor road vehi- cles during the peak hour. 6-20 Number of Accepted Gaps >t Number of Gap (t) (s) Rejected Gaps >t 1.5 92 3 2.5 52 18 3.5 30 35 4.5 10 62 5.5 2 100arrow_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
- 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.arrow_forwardProblem 5 The crash rate on a heavily-traveled two-lane rural highway is abnormally high. The corridor is 14 miles long with an AADT of 34,000. An investigation has determined that head-on collisions are most common, with an RMVMT of 4.5, and are caused by vehicles attempting to pass. Addition of a passing lane has been observed as an appropriate countermeasure with a CMF of 0.65. Calculate the estimated yearly reduction in total crashes.arrow_forwardA 1.5-mile section of a two-lane road has an AADT of 10,000. In a three-year period, there have been 6 fatal accidents and 12 non-fatal accidents. The state allows 350 accidents per 100 mvm for three years, of which 100 are fatal. For which value of confidence level, this highway is considered safe? If the following countermeasures are implemented: widening the existing lane by 2 feet, and widening the existing shoulder by 2 feet paved, and widening the clear zone by 5 feet, what will be the number of accidents reduced if the AADT became 12,000?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Traffic and Highway EngineeringCivil EngineeringISBN:9781305156241Author:Garber, Nicholas J.Publisher:Cengage Learning
Traffic and Highway Engineering
Civil Engineering
ISBN:9781305156241
Author:Garber, Nicholas J.
Publisher:Cengage Learning