@article{ref1,
title="The effect of higher speed limits on crash-injury severity rates: a correlated random parameters bivariate tobit approach",
journal="Analytic methods in accident research",
year="2022",
author="Ahmed, Sheikh Shahriar and Alnawmasi, Nawaf and Anastasopoulos, Panagiotis Ch. and Mannering, Fred",
volume="34",
number="",
pages="e100213-e100213",
abstract="Over the last few decades, interstate speed limits in different US states have been increased from 70 mi/h to 75 mi/h or 80 mi/h, even to 85 mi/h in some instances. The implication of such speed limit increases on crash likelihoods and resulting injury severities is a key concern. To understand the impact of speed limit increases on no-injury and injury crash rates (including fatalities) multi-year segment-specific freeway crash data from the state of Kansas (including both pre-, and post-speed limit increase crash information) are modeled using a correlated random parameters bivariate tobit model. To address possible temporal variations in the effects of explanatory variables across years, year-specific models were estimated. Model estimation results indicate that several traffic, segment geometry, and pavement-specific characteristics affect no-injury and injury crash rates. From the year-specific model estimation results it was determined that the effects of the factors affecting pre- and post-speed limit crash rates did change significantly over time. However, such changes were also observed in the pre-speed limit increase years, as well as the post-speed limit increase years. While findings do suggest a small but statistically significant increase in injury crash rates after speed limits were raised, temporal changes in the effects of factors contributing to no-injury and injury crash rates make it difficult to isolate the true impacts of increased speed limits.<p /> <p>Language: en</p>",
language="en",
issn="2213-6657",
doi="10.1016/j.amar.2022.100213",
url="http://dx.doi.org/10.1016/j.amar.2022.100213"
}