Highway Safety Manual applied in Missouri - freeway/software.

DTRT13-G-UTC37AASHTO\u2019s Highway Safety Manual (HSM) facilitates the quantitative safety analysis of highway facilities. In a 2014supplement, freeway facilities were added to the original HSM manual which allows the modeling of highwayinterchanges. This report documents the calibration of the most vital freeway interchange facility types in Missouri. Thesefacility types include nine freeway interchange terminals, including diamond, partial cloverleaf, and full cloverleafinterchanges. The non-terminal facilities included entrance and exit speed-change lanes, and entrance and exit ramps. Thecalibrated facilities applied to both rural and urban locations. For each facility type, sample sites were randomly selectedfrom an exhaustive master list. Four types of data were collected for each site: geometric, AADT, traffic control, and crash.Crash data was especially noteworthy because of the crash landing problem, i.e. crashes were not located on the properinterchange facility. A significant companion crash correction project was undertaken involving the review of 12,409 crashreports, and the detailed review of 9,169 crash reports. Using the corrected data, 44 calibration values were derived forfreeway terminal and non-terminal facilities. These values are the first reported freeway interchange calibration valuessince the release of the 2014 HSM supplement