Write Up:

Interstates are the arteries that connect the nation and keep people and commerce flowing. When interstates shut down in Missouri, the country is cut in half. Keeping interstates free flowing is a top priority for MoDOT, but sometimes unplanned incidents affect the department’s ability to keep the interstates moving.  An unplanned incident can be weather related, emergency road and bridge repair, traffic crashes or other incidents. 

Of the types of unplanned incidents that can occur, traffic crashes create most of the impacts.  Using the nationally adopted Highway Safety Manual, an expected crash number is established for each direction of IS70 and IS44 per county.  The expected crash number is determined by the traffic volume, roadway characteristics (e.g. number of lanes, lane width, shoulder width, horizontal curves, etc.), calibration factors to local conditions and reported crash data over a five-year period.  The expected crash number provides a glimpse into the number of crashes one could expect to occur during normal conditions and can help identify opportunities for improvement.  When the number of observed crashes is higher than the expected crash number, this could indicate an opportunity for roadway improvements to help reduce the number of crashes. Identifying these locations can help the department prioritize potential improvements. 

Across both corridors there was an uptick in observed crashes between the data ending in 2017 and data ending in 2018.  This is the first quarter for this measure to be presented and will serve as a baseline to judge success by.  

Purpose of the Measure:

Measure the crash performance of I-44 and I-70 utilizing national analytical standards in order to identify locations which have an opportunity for positive change.

Measurement and Data Collection:

The limits of the interstates analyzed are as follows:

I-44: Oklahoma State Line to Route 100 in Gray Summit

I-70:  Route 7 in Blue Springs to Route Z in Wentzville

Observed crashes are pulled from MoDOT's Transportation Management System and represent all reported crashes which occurred between the limits on each interstate.  The miles used to determine the crash per mile are also pulled from MoDOT's Transportation Management System.  Expected crash per year per mile numbers were calculated using the ISATE spreadsheets developed with the American Association State Highway Transportation Officials  Highway Safety Manual.