01625668

Component

This paper presents an investigation into the safety effects of an advisory variable speed limit system deployed along OR-217 freeway in Portland, Oregon. This system is part of OR-217 active traffic management project which is intended to address the numerous safety and mobility challenges along the corridor. Due to the limited available crash data after system deployment, the study utilized surrogate safety measures besides crash data in assessing the safety impacts of the system. These surrogate measures included speed and speed variability at a point location, across the two directional lanes of travel, and between locations along the corridor. Analysis of crash data showed a decrease in total crash frequency and rate including rear-end crashes. At a point location, the system was found to generally reduce mean speed and speed variability within the same lane and between the median and shoulder lanes. Further, study results suggest that the system could significantly reduce speed variation between locations along the corridor which should contribute to more gradual change in speeds and its associated acceleration and deceleration. Lastly, the study found that intermittent activation of the advisory VSL system for brief periods of time (a minute or two) could bring negative impacts on speed variation.

This paper was sponsored by TRB committee AHB15 Standing Committee on Intelligent Transportation Systems.

01618707

17-04130

English

21p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References (45) ; Tables

Crash rates; Highway traffic control; Transportation corridors; Urban highways; Variable speed limits

Portland (Oregon)

Highways; Operations and Traffic Management; Safety and Human Factors

Transportation Research Board Annual Meeting 2017 Paper #17-04130

TRIS, TRB, ATRI

Dec 8 2016 11:34AM