Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Report
Driver Qualification is a treatment that involves the prior training of drivers. Thus, it is not a
treatment applied to a particular facility type. The safety aspect of this treatment could improve
travel-time reliability by reducing traffic disruptions caused by impaired drivers.
Automated Enforcement
Automated enforcement involves the use of speed-enforcement cameras along arterial and local
roads and red-light-running cameras at signalized intersections. These cameras can be applied in a
variety of area types (urban, suburban, and rural) to reduce speeds and to reduce red-light running.
Probe Vehicles
Probe vehicles and point detection treatments such as GPS, Video Detection, Microwave Radar,
and Bluetooth MAC Readers are treatments used by agencies for vehicle detection as a means to
provide near-real-time travel-time estimation. They can be applied in a variety of different area
and facility types. Assessing congestion (and changes in travel-time reliability) in busy corridors
and exploring alternative routes are some of the possible applications for this treatment.
Geometric Design Improvements
Geometric improvements involve spot reconstruction or minor geometric widening within existing
paved areas of all facility types. This treatment can be applied within a relatively small section of
roadway or at an intersection and includes such features as auxiliary lanes, flyovers, interchange
modifications, narrow lanes, temporary shoulder use, and minor alignment changes. Many major
metropolitan areas in the United States have examples of spot geometric design treatments being
(4, 5)
used to address freeway bottlenecks.
Variable Speed Limits (VSL)
This treatment is applied to freeway facilities to vary the facility speed limit on the facility as it
approaches capacity at a bottleneck. Its use has predominantly been seen in larger urban areas and
is in widespread use on freeways in the Netherlands and Germany. VSLs can also be applied in
work zones to homogenize traffic flow.
OPERATIONS STRATEGIES AND TREATMENTS TO IMPROVE TRAVEL-TIME RELIABILITY Page 86