approach to highway safety is to identify locations with a higher than expected
number of crashes and then diagnose the location for appropriate
countermeasures. This site analysis
approach (or hot spot) has been a successful practice around the nation. A new approach has since emerged, first
called “systematic”, where DOT’s initiate programs to deploy widespread
low-cost cost-effective countermeasures.
In an ideal world these would be deployed everywhere, but because of
limited staff and budgets this might not be the preferred method. In the real world of limited budgets, DOT’s
cannot afford to apply treatment equally at all locations except for where
these applications have extremely low cost and are effective.
In most cases, DOT’s
have chosen to employ low cost countermeasures where they are the most
effective, locations where there are crashes targeted by the
countermeasures. This is now referred to
as “systemic”. Previous studies in this
area may have referred to this as “systematic”, so understandably there can be
confusion about what is “systematic” and what is “systemic”. To further add to the confusion, some
research now refers to approaches that identify risk factors for targeted
crashes as “systemic”. For now, Oregon
DOT is using the term systematic and systemic virtually synonymously.
The systemic (or
systematic) approach, as it has been used at Oregon DOT, refers to using
analytical techniques to identify locations (or corridors) that either display
a higher than expected number of target crashes or high risk roadway
characteristics for the target crashes (i.e., high speeds, numbers of lane,
absence of a median). This approach may
identify locations or corridors that may not typically be identified through a
traditional hot spot analyses. This
approach compliments the traditional approach by analyzing target crash types
that typically result in severe crashes and may be widely distributed over the
system, and thus not show up in a traditional hot spot approach.