01673136

Component

https://doi.org/10.1177/0361198118783162

A Policy on Geometric Design of Highways and Streets, 6thEdition, (publisher: AASHTO), provides design criteria for minimum sight distances, including intersection sight distance (ISD). An understanding of the relationship between ISD and safety at stop-controlled intersections is needed, with potential applications of this knowledge to both performance-based design and substantive road safety management practices. To establish this relationship, crash, traffic, and geometric data were collected from 832 two-lane minor unsignalized intersection approaches in Ohio, and Washington. The data were analyzed using a cross-sectional study design to quantify the relationship between safety and ISD. The analyses indicated that the expected number of target crashes are associated with available ISD. Target crash frequencies increase as available ISD decreases. Results suggest that ISD is associated with expected crash frequency in a non-linear fashion. The sensitivity of the expected number of target crashes to changes in ISD is highest when ISD is shorter, and decreases as ISD increases (i.e., the safety benefit of increasing ISD from 300 to 600 ft is substantially larger than the safety benefit of increasing ISD from 1,000 to 1,300 ft). The results also suggest that the impacts of ISD on crash frequencies vary as a function of the major road two-way annual average daily traffic and the major road speed limit. The sensitivity of the expected number of crashes to changes in ISD increases as both traffic volume and speed limit increase. Crash modification functions for each of the target crash types were estimated using the regression models.

18-05576

English

pp 11-19

2018-12

Transportation Research Record: Journal of the Transportation Research Board

Digital/other

Figures (2) ; References (10) ; Tables (3)

Crash modification factors; Crash rates; Design standards; Geometric design; Highway safety; Sight distance; Traffic crashes; Unsignalized intersections

North Carolina; Ohio; Washington (State)

Design; Highways; Operations and Traffic Management; Safety and Human Factors

TRIS, TRB, ATRI

Dec 22 2017 10:39AM

• A Framework for Prioritizing Urban Arterial/Freeway Interchange Types using Multi-Criteria Analysis
• A Model of the Probability of a Cross-Median Crash When a Vehicle Fully Crosses the Median
• American Complete Streets and Australian SmartRoads: What Can We Learn from Each Other?
• Assessing Roadway Contributions to Stormwater Flows, Concentrations, and Loads with the StreamStats Application
• Automated Extraction of Horizontal Curve Attributes using LiDAR Data
• CFD-DEM Two-Way Coupled Numerical Simulation of Bridge Local Scour Behavior Under Clear-Water Conditions
• Development of a Standardized Buttress for Approach Guardrail Transitions
• Development of Transition between Free-Standing and Reduced-Deflection Portable Concrete Barriers
• Enhanced Design Guidelines for Interchange Loop Ramps
• Enhanced MASH TL-3 Short-Radius System: Promising Design to Accommodate Flat Terrain and Ditches
• Full-Scale Performance Evaluations of Various Wire-Backed Nonwoven Silt Fence Installation Configurations
• Highway Cross-Slope Measurement using Mobile LiDAR
• Human Personality Based Investigation on Distance Threshold for Freeway Landscape Pattern
• Identification and Calculation of Horizontal Curves for Low-Volume Roadways Using Smartphone Sensors
• Mitigation of Impacts to Groundwater Quality from Highway Runoff in a Karst Terrain
• Safety Impact of Weaving Distance on Freeway Facilities with Managed Lanes using Both Microscopic Traffic and Driving Simulations