A Simple Before-After Crash Study was performed for 900 West between North Temple St and 1700 South. Three years of before project crash data was compared to three years of after project crash data. The construction period for the project was July 1, 2017 – December 31, 2017. Crashes that occurred during the construction period are not included in the analysis since they likely do not represent typical roadway conditions.

Before and after years for the study are as follows:

“Year -3” = July 1, 2014 – June 30, 2015
“Year -2” = July 1, 2015 – June 30, 2016
“Year -1” = July 1, 2016 – June 30, 2017
“Year +1” = January 1, 2018 – December 31, 2018
“Year +2” = January 1, 2019 – December 31, 2019
“Year +3” = January 1, 2020 – December 31, 2020

The Crash Types graph above indicates that for Years +1, +2 and +3, all crash types either decreased or remained about the same, as compared to the three years before project installation, except for rear-end crashes which show a pronounced increase initially but returned to average levels by year +3. To better understand the principal causes of the rear-end crashes, rear-end crashes for all years were analyzed and are shown in the graph below.

For questions about this crash study, please feel free to call the Transportation Division office at 801-535-6630.