ALDOT Statewide TSMO Program Plan ALDOT Statewide TSMO Program Plan 20190522REV | Página 7

3 THE BUSINESS CASE FOR TSMO
Alabama has more than 102,000 miles of roadway in the state as identified by FHWA Highway Statistics
and ALDOT’s Highway Performance Monitoring System (HPMS); out of which 10,900 centerline roadway
miles are maintained by the State (FHWA, 2018) (ALDOT, 2017). While roadways maintained by ALDOT
consist of only 10% of the total centerline miles in Alabama, the state-maintained roads carry
significantly more traffic and freight than local roads and represent the critical connections between
communities—what happens on these roads substantially impacts the quality of life for Alabamians
throughout the state.
3.1 SAFETY AND MOBILITY CONCERNS
Safety and mobility are independently necessary concerns within any transportation system, however,
the inherent relationship between safety and mobility places added importance and complexity to
isolating and solving these concerns. Alabamians experience a variety of safety and mobility challenges
every day—from an increased commute time due to a fender bender; to a road closure due to an
overturned tractor trailer; to a traffic fatality.
3.1.1
Safety
Traffic incidents such as stalled vehicles, major and minor
crashes, and spilled freight loads account for one-fourth of all
delays on the highway system in Alabama (ALDOT, 2018).
Each minute a lane is blocked can lead to four minutes of
delay which can mean a 30-minute lane blockage resulting in
a potential two-hour distribution in traffic (FHWA, 2010)
(SHRP 2, 2014). Importantly, for each minute that a primary
incident continues, the likelihood of a secondary crash
increases by 2.8% (FHWA, 2010). The United States
Source: The Anniston Star
Department of Transportation (USDOT) estimates that
secondary crashes represent more than 20% of all crashes on freeways and 18% of fatalities on interstates
(FHWA, 2010). Fewer incidents and quicker clearance of incidents help to reduce congestion, allowing the
transportation system to operate more safely and efficiently.
3