Evaluation of roadway departure treatments after they are installed to determine effectiveness can be used to guide future decisions regarding roadway departure countermeasures.
A record of crash history and countermeasure installation forms the foundation for assessing how well implemented strategies have performed. An important database to keep is a current list of installed countermeasures with documented "when/where/why" information. Periodic assessments will provide the necessary information to make informed decisions on whether each countermeasure contributed to an increase in safety, whether the countermeasure could or should be installed at other locations, and which factors may have contributed to each countermeasure's success.
In order to perform the assessment, it is necessary to collect the required information for a certain period after strategies have been deployed at the locations. The time period varies, but should be no less than one full year (with 2-3 years preferred). The information required may consist of public input and complaints, police reports, observations from maintenance crews, and local and State crash data.
It is important to keep the list of strategy installations up to date since it will serve as a record of countermeasure deployment history (see Table 2 for an example). By using this type of system, assessment dates can be scheduled to review the crashes and other pertinent information on segments where roadway departure countermeasures have been installed.
Action: Develop a spreadsheet to track future safety project installations and record 3 years of "before" crash information at those locations.
|Type of Countermeasure Installed
|Middlebrook Pike, 1 mile north of Running Cedar Rd.
|Advanced Curve Warning Sign
|3 in 3 years
|Subdivision built in Summer 2010 near this location.
|Route 657; 1/2 mile south of Glade Drive
|5 in 3 years
|Traffic volume has increased 25% between the installation date and the "after" period.
|Clifton Road; South of Veirs Mill Road
|Speed Limit Signs
|2 in 1 year