01334147

Component

This paper presents results of a study that developed statistical models relating crashes occurring in functional areas of median openings to spacing, type, and location of the openings. The objective of the study was to evaluate the impact of spacing, type and location of median openings on total crashes, severity and type of crashes. Other factors considered are posted speed limit, arterial average annual daily traffic (AADT), number of driveways and land use types. A total of 112 median openings located on 11 arterials with raised medians in the Las Vegas valley were used in the analyses. Results show that very short and very long spacings between median openings are associated with high number of total and injury crashes. Optimal spacings are found in the range of 342 to 729 feet depending on speed and type of crashes. Moreover, as expected, directional median openings that do not allow left-turns out of the land uses have significantly lower number of total crashes by 20-50% than the full median openings that allow all turning movements. This range in crash reduction is in agreement with results reported in other studies. Other types of median openings, which allow lesser number of left turn movements, have lesser number of crashes than directional median openings. It is expected that the results of this study will assist transportation agencies in updating existing and developing new Access Management (AM) strategies related to spacing of median openings.

01329018

11-2269

English

21p

2011

Transportation Research Board 90th Annual Meeting

DVD

Figures; Photos; Tables (17)

Arterial highways; Crash causes; Crash severity; High risk locations; Left turns; Median openings; Traffic crashes; Traffic safety

Crash reduction factors

Las Vegas (Nevada)

Highways; Planning and Forecasting; Safety and Human Factors; I72: Traffic and Transport Planning

Transportation Research Board Annual Meeting 2011 Paper #11-2269

TRIS, TRB

Feb 17 2011 6:07PM