Road Weather Information Systems (RWIS) have been developed by transportation agencies to address operational and safety challenges associated with weather. Researchers conducted a comprehensive review and assessment of Montana DOT’s RWIS program, which includes 73 RWIS stations throughout the state, to assess needs and compare expansion and enhancement scenarios. The goal of the study was to ensure the efficient use of weather data in various transportation applications and the optimum use of agency resources.
Researchers used workshops, surveys, and interviews with Montana DOT personnel to conduct a RWIS needs assessment. Findings included a number of key lessons including:
- Maintenance personnel need access to key weather and road-related data. Desired data includes camera images, pavement conditions, air temperature, pavement temperature, wind speed and direction, precipitation type and occurrence, and visibility.
- Provide more RWIS sites with basic equipment and near maintenance section boundaries. Having more sites with only a camera and pavement temperature sensor can be more beneficial compared to fewer sites with more sensors per site.
- Update camera images and RWIS data every 15 minutes or less. Fifteen minutes can make a considerable difference in terms of winter maintenance treatments, especially at the start of a storm.
- Be aware that the most problematic pieces of equipment from a maintenance perspective, pan-tilt-zoom (PTZ) cameras, are also the most valuable. PTZ cameras give a better view of overall weather conditions but tend to fail more often than fixed cameras.
- Plan for occasional cellular communication outages. Cellular communications are the main source of outages, and those outages are largely out of the agency’s control.
- Certain sensor and camera technologies may be desirable. Technologies reported to be desirable included non-invasive sensors, more robust precipitation sensors, visibility sensors, live video, and cameras with the ability to produce images in the dark.
- Provide mobile RWIS with caution. These are not generally desired by section supervisors and maintenance superintendents, but more interest is shown at the level of maintenance chief.
- Harness the power of traveler information feedback. The public (via traveler information systems) may be the most common method for the agency to learn of unavailable or malfunctioning sensors or RWIS sites.
- Note that RWIS may serve as a secondary data source for aviation users. Camera images with horizon views, and especially those near mountain passes, may be the most valuable RWIS information for aviation.