Evaluation of the Effectiveness of Stop Lines in Increasing the Safety of Stop-controlled Intersections
Evaluation of the Effectiveness of Stop Lines in Increasing the Safety of Stop-controlled Intersections

Author: Melissa Duhn

Publisher:

Published: 2020

Total Pages: 200

ISBN-13:

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Stop lines are ubiquitous, but do they really impact intersection safety? Prior to this project, no long-term studies on intersection safety with stop lines had been completed. This project was developed with two parallel research efforts: a safety study and an observational study. The safety study was developed to address stop lines’ effects over the long term and used crash data from five cities’ stop-controlled intersections to perform regression and see if stop lines actually influenced safety. The observational study was developed to determine if stop lines have an effect on driver behavior at intersections and to look at where drivers were stopping. Video was collected at 16 different intersections before and after a stop line was painted. The safety study and observational study showed that stop lines did not have a significant impact on driver behavior or intersection safety, but other factors like speed limits and sight distance did. Implications for practice include carefully examining sight distance at the intended stopping point to ensure drivers have adequate sight distance in both directions. If sight distance is not adequate, moving the intended stop location or reconsidering whether the intersection should have signage -- stop or yield -- or be uncontrolled could yield better driver compliance and safety.

Safety Evaluation of Multiple Strategies at Stop-controlled Intersections
Safety Evaluation of Multiple Strategies at Stop-controlled Intersections

Author: Thanh Le (Highway engineer)

Publisher:

Published: 2018

Total Pages: 88

ISBN-13:

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The Development of Crash Modification Factors program studied the safety performance of various stop-controlled intersections for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated the safety effectiveness of multiple low-cost treatments at stop-controlled intersections. Improvements included basic signing and pavement markings. This strategy is intended to reduce the frequency and severity of crashes at stop-controlled intersections by alerting drivers to the presence and type of approaching intersection. Geometric, traffic, and crash data were obtained at three- and four-legged, two- and four-lane major road, and urban and rural stop-controlled intersections in South Carolina. To account for potential selection bias and regression to the mean, an empirical Bayesian before-after analysis was conducted, using reference groups of untreated intersections with similar characteristics to the treated sites. The analysis also controlled for changes in traffic volumes throughout time and time trends in crash counts unrelated to the treatments. The aggregate results indicate reductions for all crash types analyzed (i.e., total, fatal and injury, rear-end, right-angle, and nighttime). The reductions are statistically significant at the 95-percent confidence level for all crash types. For all crash types combined, the crash modification factors (CMFs) are 0.917 for all severities and 0.899 for fatal and injury crashes. The CMFs for rear-end, right-angle, and nighttime crashes are 0.933, 0.941, and 0.853, respectively. The benefit-cost ratio estimated with conservative cost and service life assumptions is 12.4 to 1 for total crashes at unsignalized intersections. The results suggest that the multiple low-cost treatments, even with conservative assumptions on cost, service life, and the value of a statistical life, can be cost effective.

Safety Evaluation of Multiple Strategies at Stop-controlled Intersections
Safety Evaluation of Multiple Strategies at Stop-controlled Intersections

Author: Thanh Le

Publisher:

Published: 2017

Total Pages: 88

ISBN-13:

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Technical summary of the FHA report FHWA-HRT-17-086 program that studied the safety performance of various stop-controlled intersections for the Evaluation of Low-Cost Safety Improvements Pooled Fund Study. This study evaluated the safety effectiveness of multiple low-cost treatments at stop-controlled intersections.

Safety Evaluation of Increasing Retroreflectivity of STOP Signs
Safety Evaluation of Increasing Retroreflectivity of STOP Signs

Author: Bhagwant Naraine Persaud

Publisher:

Published: 2008

Total Pages: 33

ISBN-13:

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The Federal Highway Administration (FHWA) organized a Pooled Fund Study of 26 States to evaluate low-cost safety strategies as part of its strategic highway safety effort. One of the strategies chosen to be evaluated for this study was STOP signs with increased retroreflectivity. This strategy is intended to reduce the frequency of crashes related to driver unawareness of stop control at unsignalized intersections. Geometric, traffic, and crash data were obtained at unsignalized intersections for 231 sites in Connecticut and 108 sites in South Carolina. In each case, the strategy was implemented as a blanket application of STOP signs with increased retroreflectivity. Empirical Bayes (EB) methods were incorporated in a before-after analysis to determine the safety effectiveness of increasing the sign retroreflectivity. There was a statistically significant reduction in rear-end crashes in South Carolina. Based on the results of the disaggregate analysis, reductions in crashes were found at three-legged intersections and at intersections with low approach volumes.

Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections
Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections

Author:

Publisher:

Published: 2009

Total Pages: 22

ISBN-13:

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"The purpose of this document is to present information on suggested effective, low-cost intersection countermeasures developed using intersection safety research results and input from an intersection safety expert panel. These low-cost countermeasures can be applied to a large number of intersections with a high frequency of crashes using a systematic approach. The net impact of such an approach can produce significant reductions in statewide intersection crashes, fatalities, and serious injuries. Low-cost countermeasures are defined as those ranging from $1,000 to $50,000 per intersection"--Page 4

The Effect of Stop Control on Ultra Low Volume Intersection Safety
The Effect of Stop Control on Ultra Low Volume Intersection Safety

Author: Ryan John Tenges

Publisher:

Published: 2005

Total Pages: 154

ISBN-13:

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It is commonly regarded that the over-use of traffic control devices desensitizes drivers and leads to disrespect, especially for low volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer's Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approaches to stop are left to engineering judgment and are usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer meet engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop controlled intersections. The scope of this research is ultra low volume (