In June 2012 USDOT finalized Version 3.0 of the Best Practices for Road Weather Management report. This report contains 27 case studies of systems in 22 states that improve roadway operations under inclement weather conditions. Each case study has six sections including a general description of the system, system components, operational procedures, resulting transportation outcomes, implementation issues, as well as contact information and references.

The previous report, Best Practices for Road Weather Management Version 2.0 presented 30 case studies from municipal and state transportation agencies. At this point, those solutions are either mainstreamed or have been surpassed by even better solutions. The Version 3.0 report captures the state-of-the-art, presenting 27 all-new practices that build upon these agencies’ previous successes.

One case study includes a high water detection system in Texas. High water detection systems (HDWS) are installed in stream beds at road and stream crossing locations with a potential or a history of flooding. The Texas Department of Transportation (TxDOT) has installed twenty such systems throughout the San Antonio area. The San Antonio district has installed one system in the metro area, while the other units have been installed in the rural areas surrounding San Antonio, primarily at locations in the Texas Hill Country, which are subject to flash flooding due to the region’s topography. The first units were installed in 2005. The unit cost is typically $75,000.

System Components: The HWDS consists of the following elements:

• A stand pipe installed in the stream bed or measuring device attached to the crossing structure (bridge or culvert)
• Wire line or wireless communications from the measuring system to the local computer
• Wire line or wireless communications from the local computer to advanced warning signs
• Advanced warning signs, with flashers
• Central/Master software
• Cellular communications from the systems to a contracted operations center
• Internet-based communications from the contracted operations center to TxDOT’s network

System Operations: The level of water in the stream bed is measured by a stand pipe or a device mounted on the bridge or culvert crossing the stream. The water level is transmitted to a local computer mounted in a cabinet near the stream crossing (which is installed above the flood elevation). The local computer activates flashers on warning signs on the approaches to the stream crossing. The local computer also transmits system status and water elevation to the central software application at the contracted operations center. Local topography for each location determined during installation and the water elevation data provided by the local computer are used to create a public Internet display. The conditions are noted as flooded or not flooded, or no data available. A secure web site is available for TxDOT staff that provides detailed information regarding each system’s status, operational history and historic water levels.