01648589

Component

https://doi.org/10.3141/2636-02

Intersections experience a disproportionate share of traffic crashes, injuries, and fatalities because of the increased number of conflicting traffic movements at these locations. These issues are particularly pronounced at rural locations where speeds are generally higher and most intersections are either stop- or yield-controlled. Ideally, intersecting roadways should be oriented at as close to a 90-degree angle as possible. However, intersection design can diverge from this preferred configuration and result in a skewed intersection. Skewed intersections have been found to cause safety and operational issues for road users. To determine the effect of intersection skewness on crash frequency, crash prediction models were estimated for rural stop-controlled intersections on high-speed two-lane highways throughout the state of Iowa. Separate analyses were conducted for three-leg and four-leg intersections. In both cases, crash frequency was estimated as a function of annual average daily traffic, skew angle, and other salient geometric characteristics. The results consistently showed crash frequency to increase with skew angle. A 10-degree deviation from 90 degrees would result in 3% more crashes at three-leg intersections and 4% more crashes at four-leg intersections. In addition, crashes were affected by the volume of heavy vehicles, whether the approaches were paved or unpaved and whether intersection lighting was present.

01626186

17-00077

English

pp 9-14

2017

Transportation Research Record: Journal of the Transportation Research Board

9780309441773

Digital/other

References; Tables

Crash rates; Highway factors in crashes; Highway safety; Intersections; Rural highways

Skew angles

Design; Highways; Safety and Human Factors

TRIS, TRB, ATRI

Oct 19 2017 2:18PM

• Alternative Approach for Combining Multiple Crash Modification Factors Using Adjustment Function and Analytic Hierarchy Process
• Application of Highway Safety Manual Method for Ramp Crash Prediction to Loop and Diamond Ramps
• Developing Crash Modification Factors for Horizontal Curves on Rural Two-Lane Undivided Highways Using a Cross-Sectional Study
• Development of Crash Modification Factors for Uncontrolled Pedestrian Crossing Treatments
• Evaluation of Safety Performance Functions Based on Experimental Design Using a Cross-Validation Method
• Exploring the Need for Region-Specific Calibration Factors
• Implementing Highway Safety Manual Life-Cycle Benefit–Cost Analysis of Safety Improvements
• Safety Effects of Low-Cost Systemic Safety Improvements at Signalized and Stop-Controlled Intersections
• Safety Performance of Flashing Yellow Arrow for Protected–Permissive Left-Turn Signal Control in Central Illinois