Safety Evaluation of Changing Speed Limit from 55 mph to 60 mph on Two-Lane, Two-Way Road Segments

Creator

Abstract

This paper describes the efforts to evaluate the safety impacts of increasing the speed limit from 55?mph to 60?mph on selected two-lane, two-way state highway road segments in Minnesota, U.S. An empirical Bayes (EB) before?after analysis was used to estimate crash modification factors (CMFs) for both segments (1,909.11?mi) and intersections (1,722 3-leg and 1,191 4-leg). Aggregate analysis conducted using all the segment and intersection data showed a 2.9% increase in total crashes, a 2.5% increase in injury (KABC) crashes, and a 0.05% reduction in the injury (KAB) crashes. These results?along with before-and-after operating speed data from another study by Minnesota Department of Transportation (MnDOT) (2019) showing that the 85th percentile operating speed remained the same and that the mean operating speeds increased by 1?mph following the speed limit increase?can lead to a conclusion that the speed limit increase from 55?mph to 60?mph had a minor effect on combined segment and intersection crashes or operating speeds. It is important to note that these results are specific to the corridors that were selected by MnDOT for the increase in speed limit; caution must be exercised when extending these to systemwide increases in speed limits in Minnesota or in other states, and when estimating long-term effects of speed limit increases as operating speeds can change over a longer period of time.

Date of publication

DOI

Identifier

Resource type

Rights statement

License

Journal title

Language

Version

ISSN

Publisher

Relations

Parents:

This work has no parents.

In Collection:

Thumbnail	Title	Date Uploaded	Visibility	Actions
	03611981221110569.pdf	2023-01-12	Public	Download