Project Info

Project Request Date: 10/01/2018
Project Requested By: Michael Vaughn, PE – Highway Safety Improvement Program
Principle Investigator: William Staats

Initial Inquiry

Below are the two primary items I would like evaluated. If you can think of other aspects of this countermeasure that can be evaluated, by all means evaluate them.

1. The targeted crash type was Roadway Departure crashes. So, was the Edgeline Only Striping countermeasure effective at reducing Roadway Departure crashes and to what degree? If you can, calculate a Benefit/Cost ratio similar to how you would calculate a B/C ratio if it were being included in the Annual Report (which we will do in the next year’s Annual Report).

2.  I would want to know if the edgeline only striping had any effect on head-ons and sideswipes. I highly doubt this countermeasure would increase head-ons and sideswipes, but I have no scientific evidence to refute the claim.

In short, I’m hoping we can show this countermeasure as having great benefit, with little, to no increase in head-ons and sideswipes.

Project Write-up

I have redone the Wilcoxon tests for KAB and KA crashes. Nothing showed a statistically significant change in proportion between the before and after period for KAB or KA crashes. However, a few scenarios occurred where all sites that did have a change in crash proportion for a particular group either all increased or decreased, but there were too few sites that changed to be able to say the change was statistically significant. Here are the summary tables for the new tests.

Data Provided

Here are summary tables for the lengths and 2016/2017 crashes for rural two-lanes, urban two-lanes, and both combined.