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Abstract:
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Rural roads are mostly undivided highways with high speed, two-way traffic.
These factors coupled with inattentive driver behavior increase the risk of frontal and
sideswipe collisions. Widening of roads and installation of barriers or medians are
expensive improvement options. Centerline Rumble Strips (CLRS) are a costeffective
countermeasure for reducing head-on and sideswipe crash types by warning
distracted drivers of lane departures that lead to an intrusion onto the adjoining lane
through tactile stimuli.
This study documents the state-of-the-practice pertaining to CLRS across the
U.S. and attempts to establish a selection criterion for identifying locations that
warrant CLRS installations. Using this selection criterion in the Critical Analysis
Reporting Environment (CARE) software, candidate segments warranting CLRS
installations in the State of Alabama were identified. Further, an economic analysis was conducted to determine the benefit to cost ratio for the selected locations by
attaching a monetary value to individual crash types, namely fatal, injury, and property
damage only (PDO) and comparing them to the cost of a CLRS installation. A 14%
reduction in the number of crashes was the expected tangible benefit of CLRS. This
value was selected from the Insurance Institute of Highway Safety (IIHS) study of 2003.
According to this study, “reliable” data from 7 states with a total 210 miles of CLRS was
analyzed and it was concluded that sites treated with CLRS had an overall reduction of
14% in lane crossover crash types. Therefore, the number of crashes represented by the
14% were determined for every segment. The savings in crash cost due to the 14%
crashes that would be prevented was the expected benefit of CLRS. The monetary
amount incurred due to the installation of CLRS was the only cost that was associated
with CLRS. Some other factors which may affect the cost of installation could be the
cost of traffic control and speed at which the CLRS installation is performed. Cost of
installation from the surveys was found to be $0.55/linear foot and was the only cost that
was associated with CLRS in this report. The value of the benefit to cost ratio was found
to be 16.5 which establishes CLRS as a cost-effective crash countermeasure. Finally, the
segments were prioritized based on the crash rates experienced on the individual
segments. |
