Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
Strategy: 3.1. Vehicle Infrastructure Integration
Category: 3. Vehicle Technologies Treatments and Impacts:
Vehicle Infrastructure Integration (VII)
• Safety: In Orlando, Florida, a simulation study of navigation devices found that drivers using the devices reduced their crash risk
by four percent as a result of improved wrong turn performance and the tendency of the system to select routes with improved
(normally safer) facilities (5).
• Mobility: Simulation study showed that VII can reduce travel time (VHT) by 22.5% if implemented in a network system (4).
Strategy: 3.2. Driver Assistance Products
Category: 3. Vehicle Technologies
TREATMENTS AND IMPACTS:
Driver Assistance Systems (Electronic Stability Control; Obstacle Detection Systems; Lane Change Assistance Systems; Lane
Departure Warning Systems; Rollover Warning Systems; Road Departure Warning Systems; Forward Collision Warning
Systems)
• Safety: A field evaluation in Michigan tested Advanced Cruise Control (ACC) combined with forward collision warning to form
an automotive collision avoidance system (ACAS). The study found that ACAS could reduce exposure to driving conflicts leading
to rear-end crashes by 8 to 23 percent and estimated that the combined system could eliminate about 10 percent of all rear-end
crashes (5).
A 1999 FHWA study suggested that lane departure warning systems have the potential to reduce road departure crashes by 10
percent for passenger vehicles and 30 percent for heavy trucks (32).
An evaluation of electronic stability control (ESC) and crash data from the Institute for Traffic Accident Research and Data
Analysis indicated that the crash rate for single-car crashes and head-on crashes decreased by about 36 percent where ESC was
expected to be effective (32).
Widespread deployment of integrated countermeasure systems could prevent over 48 percent of rear-end, run-off-road, and lane
change crashes (32).
• Mobility: In-vehicle navigation/route guidance devices can reduce travel times by 4 to 10 percent under normal traffic conditions
or recurring traffic congestion (1).
ADDITIONAL DESCRIPTION AND QUANTITATIVE BENEFITS OF TRAVEL-TIME RELIABILITY STRATEGIES Page F-28