Date: June 16, 2023
Author(s): Michael Rosen
Abstract
Removing a center turn lane from a three-lane road does not appear to interfere with safety goals. In fact, in some cases, it appears it may improve safety. I compared streets with a center turn lane to those that once had a center turn lane, but later removed it. The streets that once had center turn lanes — but later removed them in favor of treatments such as bike lanes — registered an average of 42% fewer crashes per million vehicle miles traveled (VMT) than the comparison streets with center turn lanes. Furthermore, the additional safety benefits held up when measuring across a selection of sub-crash groups, such as fatal and severe crashes and pedestrian and bicycle collisions. While a before-and-after analysis suggested that part of this effect can be attributed to lower crash densities on our treatment streets, this did not invalidate the fact that these streets still observed absolute reductions in crash rates after the removal of a center turn lane, suggesting that center turn lane removal can coexist with safety objectives.
About the Project
This capstone project was completed in partial satisfaction of the requirements for the degree Master of Urban & Regional Planning at the UCLA Luskin School of Public Affairs.