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Weather
Applications >
What is it?
- Variable message signs (VMS), highway advisory
radio (HAR), variable speed limit signs (VSL), traffic sensors,
and traffic management centers (TMC) are ITS technologies that
monitor and control traffic in adverse weather conditions.
- Most ITS technologies that control traffic in
adverse road conditions are integrated with other weather-related
ITS technologies (i.e. they have weather forecasting or road maintenance
capabilities).
Key Results
- VMS are the most widely used traffic control
device because they are highly visible.
- Drivers prefer VMS to Highway Advisory Radio
(HAR) because of low interest level in unadorned HAR traffic weather
reports.
- Vehicle control systems like Weather-related
use of Intelligent Speed Adaptation (WISA) were very effective
at controlling vehicle speeds in poor road weather conditions.
Benefits
- Warning devices like VMS lead to fewer weather-related
road accidents.
- Traffic control devices like Weather-Related
Intelligent Speed Adaptation (WISA) are generally successful at
lowering mean speeds and standard deviation, which in turn result
in fewer accidents.
Costs
- VMS: Capital Cost: 10-50k, Operation and Maintenance:
1.9-4.1k per year
- ISA: estimated cost of equipment is $226-$2265
- HAR: Capital Cost: 16-32k, Operation and Maintenance:
0.6-1k per year
- VSL: Capital Cost: 3.7-5k, Operation and Maintenance:
Not provided
Implementation and Operational Challenges
- VMS may be ambiguous or misinterpreted by drivers;
VMS may also take driver attention away from other important driving
tasks.
- Drivers may be resistant to vehicle control systems
like WISA.
Where is it implemented?
- Traffic control systems are implemented across
the United States, particularly in those areas affected by severe
weather conditions. Each state has its own system that controls
traffic in different kinds of weather conditions.
Author: Lauren Smith
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