Environmental Sensor Station
Weather information systems (WIS) consist of the hardware, software and communications interfaces necessary to provide real-time information
on weather conditions to transportation agencies and their customers. They provide data on road, tidal/offshore and other weather-related conditions.
WIS includes satellite weather information, environmental sensor stations (ESS) that use atmospheric sensors, pavement and sub-surface
sensors, and water-level sensors to monitor weather conditions. Information gathered is then sent to traffic managers, information service providers (ISPs),
dynamic message signs, emergency personnel and other environmental monitoring networks.
A transit agency's bus, para-transit, van, and rail lines can be adversely affected by weather conditions. Transit agencies can either implement their
own WIS or sometimes they can access existing WIS and weather networks such as the National Weather Service. Sharing information with transit agencies
allows them to make intelligent decisions regarding how they are going to respond to weather-related conditions. For instance, a transit agency with a
ferry service may receive marine weather advisories and reroute traffic to land-based transportation.
Weather impacts the nation's roads and accounts for 7,000 fatalities, 800,000 injuries and $42 billion in economic costs each year1. Drivers endure over 500 million hours of delay due to fog, snow and ice. It also significantly impacts offshore marine,
air traffic and rail operations. Every mode of transportation is affected by the weather and may benefit from increased ability to receive, analyze and
disseminate weather-related information.
To reduce the impact of adverse weather conditions on surface transportation users, in 2004 the U.S. Department of Transportation (DOT) Road Weather Management
Program established the Clarus Initiative. The goal of this initiative was to integrate a data collection, quality-checking and data-dissemination system
that could provide near real-time atmospheric and pavement information. The data collected includes information from: road weather information systems
(RWIS), environmental sensor stations (ESS), and mobile observations from AVL equipment installed in vehicles. The overall objective of Clarus is to provide
information to transportation managers and travelers to manage the effects of driving in adverse weather.
Another road weather management program sponsored by the U.S. DOT is the Maintenance Decision Support System (MDSS). MDSS is a decision support tool that
integrates relevant road weather forecasts, maintenance rules of practice, and maintenance resource data to provide winter maintenance managers with recommended
road treatment strategies. MDSS is more effective, and therefore more prevalent, as a state DOT application than as a transit agency application.
Clarus User Needs Diagram
The Road Weather Connected Vehicle Applications (RWCVA) are the next generation of applications and services that assess, forecast, and address the impacts
that weather has on roads, vehicles, and travelers. These applications build on the Clarus Initiative, which delivered an integrated network of road weather
information. Through additional research, technology development, and community outreach, RWCVA will develop specificity regarding the impact that weather
has on roadways and promote strategies and tools that mitigate those impacts. The vision for the RWCVA research is to broaden road weather data to include
mobile sources and to improve the ability to detect and forecast road weather and pavement conditions by specific roadway links.
The RWCVA Program seeks to:
- Improve safety by reducing crash risks due to inclement weather, increase awareness among agencies and users of the real-time conditions, and restore
safer driving conditions more quickly and efficiently.
- Increase mobility by restoring capacity, reducing delays, and creating more uniform traffic flow.
- Increase productivity and reduce operation costs by optimizing the use of labor, pavement treatments, and equipment.
1 Weather Information for Surface Transportation Report
As with electronic fare payment (EFP), weather information systems are generally deployed as a stand-alone technology that communicates with the central
transit management center (TMC). Using pavement sensors installed on transit vehicles, automated vehicle location (AVL) technology can be used to report
pavement conditions to dispatchers in the TMC. Dispatchers can use this information to communicate route-changes, emergency responses and other messages
to their drivers. Transit Communications Interface Protocols (TCIP) practices and protocols should be used when integrating systems together into the
TMC central software.
Factors to Consider
Weather information systems can provide benefits to an agency of any size. However, system implementation costs can be high and they may be difficult
to finance for smaller or rural agencies. Transit agencies may find that developing networks with other agencies that desire or use weather-related information
can be an effective cost-mitigation strategy. If an agency only requires basic data, obtaining access to satellite-based information may be sufficient
to meet their needs. WIS seeks to take existing weather detection, computer, and communications technologies and apply in them in an integrated way to
increase the safety and efficiency of road transportation.
MTA Weather Sensor installed on a light pole
- Develop a structured procurement plan and performance-oriented requirements and specifications.
- Involve staff from various departments and outside stakeholders, such as contractors that may provide transportation or weather services or may be (eventually)
linked to the transit agency service and WIS network.
- Visit transit agencies (or non-transit agencies) providing similar transportation or weather information services and discuss their WIS systems and related
- Perform rigorous testing of the entire system to identify areas where more WIS tools/coverage are needed.
- Consider installing backup systems to ensure undisrupted communications and data storage in case of failure by the main network.
- Develop standard data-exchange protocols using TCIP in order: to allow the use of equipment from multiple vendors; to operate on different bandwidths;
and to communicate with different technologies.
- Equip all systems with virus and firewall protection.
- Expect learning curves as customers and agency staff transition to WIS and various response scenarios.
- WIS can be independent or integrated with other related intelligent transportation systems (ITS). However, equipment from multiple vendors and among different
regional area transit agencies may require special attention when planning and integrating a new WIS system.
- Transit systems associated with WIS should be linked with the communications networks used by information technologies.
- WIS requires a power supply and communications system such as fiber optic cable or wireless to provide data remotely to the TMC.
Benefits and Costs
Implementing a WIS can improve a transit system’s overall performance during weather events by:
- Reducing agency costs for weather-related maintenance and operations activities.
- Reducing the number of crashes attributed to adverse weather.
- Reducing transit delays due to fog, snow, and ice events.
Equipment and Implementation
Heat kinks in rail tracks due to extreme heat
WIS vary in cost depending on the number of pavement sensors and the type of weather instrumentation included with the weather station and the central
software. Stand-alone software will be less costly than integration of the WIS software with existing TMC software.
An entry-level WIS site would cost around $20,000 for the equipment and the installation costs vary between $15,000 and $20,000.
Operations and Maintenance (O&M)
A transit agency would work with their state DOT to access WIS information. This would be done through remote communication connections between control
centers to monitor pavement conditions that may affect transit operations. Standard operating procedures can be set up between the transit operator and
the state DOT to share road condition information.
Transit agencies monitor the National Weather Service for extreme weather conditions, such as snow, ice, fog, flooding, severe heat/cold, or high winds
and adjust transit operations accordingly.
Extreme heat can cause kinks or buckles in rail tracks, which can lead to train derailment. Additional track inspectors may be needed to monitor tracks
for this condition during periods of extreme heat.
Various web-based training courses on road weather management sponsored by FHWA are available at http://ops.fhwa.dot.gov/weather/.
Context/Success of Deployment
Kansas Department of Transportation
700 SW Harrison
Topeka, KS 66603
Weather information is provided to travelers
It’s 511 traveler information system includes weather-related driving conditions. Website also has WIS maps that display atmospheric weather.
Massachusetts Bay Transit Authority (MBTA)
10 Park Plaza
Boston, MA 02116
The agency performs additional track inspections during heat waves
Frequent inspections during heat waves are conducted to monitor track kinking, which can cause derailments.
Ohio Department of Transportation
1980 West Broad Street
Columbus, OH 43223
Environmental sensor stations (ESS) data are used by ODOT maintenance personnel to make road treatment decisions to control snow and ice.
Metropolitan Transit Authority Bridges and Tunnels
New York, NY 10035
14 above-ground atmospheric sensors
Road weather information system used at all seven MTA bridges measure wind speed,rain and snow to implement speed restrictions and restrict crossing.
- ITS ePrimer (U.S. DOT ITS Joint Program Office) - Module 7: Public Transportation
- Climate Change, Extreme Weather Events, and the Highway System Volume 2 Practitioner’s Guide and Research Report, NCHRP Report 750, 2014, http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_750v2.pdf
- ITS Research Success Stories: Clarus, ITS JPO, March 2014, http://www.its.dot.gov/clarus/
- Road Weather Management Program Frequently Asked Questions, U.S. Department of Transportation, Federal Highway Administration, August 2013,
- Road Weather Management Performance Measures – 2012 Update, FHWA-JPO-13-87, August 2013,
- Surveillance, Monitoring and Prediction, U.S. Department of Transportation, Federal Highway Administration, July 2013,
- ITS Strategic Research Plan 2010-2014: Transforming Technology through Connectivity, http://www.its.dot.gov/strategic_plan2010_2014/#one
- Best Practices for Road Weather Management, June 2012, http://ops.fhwa.dot.gov/publications/fhwahop12046/fhwahop12046.pdf
- Heat Wave Causes Kinks in Rail Tracks, July 2010, http://www.pbs.org/newshour/rundown/heat-wave-causes-kinks-in-rail-tracks/
- Weather Sensors Help MTA Bridges and Tunnels Keep Customers Safe, December 2009,
- Intelligent Transportation Systems Benefits, Costs, Deployment, and Lessons Learned, 2008 Update, U.S. DOT, September 2008,
- Weather Applications and Products Enabled Through Vehicle Infrastructure Integration (VII), January 2007,
- Maintenance Decision Support System (MDSS), U.S. DOT, FHWA, 2006, https://www.fhwa.dot.gov/resourcecenter/teams/operations/ops_mrt1.pdf
- Concept of Operations for Clarus – The Nationwide Surface Transportation Weather Observing and Forecasting System, August 2005,
- Managing Demand Through Traveler Information Services, U.S. DOT FHWA, FHWA-HOP-05-005, 2005,
- Satellite Weather Information and Intelligent Transportation System, White Paper for PhD Lab Rotation, Author: Mohammed Ali, October 2004,
- Development of a Road Weather Information System (RWIS) for Florida's Intelligent Transportation System, FDOT Contract #BD-160, Phase I Final Report, June 2004
- Weather Information for Surface Transportation: National Needs Assessment Report, FCM-R18-2002, December 2002,
Request report from OFCM
- Road Weather Information Systems: Enabling Proactive Maintenance Practices in Washington State, March 2002,