Gallagher, Mark

Mounting video cameras on winter maintenance vehicles can assist with operational decisions and enhance situational awareness for operators. To help agencies maximize the benefits of these systems, this project conducted a state-of-the-practice literature review, survey and interviews to identify types, uses and best practices for on-vehicle camera systems. Among the agencies surveyed, the most common use was a rear-view device, but cameras are also used to monitor material spreaders, underbody plows and tow plows to verify operation and effectiveness. Several best practices emerged from the research and interview process. These included: • Cameras should be carefully positioned so they do not interfere with driver sight lines or getting into or out of the vehicle. • Cameras should have washer systems and heated lenses, as accumulation of dirt or snow can rapidly degrade image quality. • Cameras are often sold as packages with washer systems. Research shows that low-cost cameras can be used with washer systems, even if they are not initially packaged with them. • In-cab displays should be carefully positioned and have driver-adjustable brightness to avoid distracting reflections on windshields. • In general, it is not recommended to integrate the video from forward-facing cameras into in-cab displays. • Transmitting live video from vehicles is currently poorly supported by cellular networks, particularly outside urban areas, and is not generally recommended. • Involving operators during the planning and installation of cameras has been shown to increase effectiveness and acceptance of the system.

This report summarizes the state of the practice in the application of advanced technologies to winter road maintenance operations. Information was captured through a combination of literature search, surveys, and interviews with key stakeholders. Several promising technologies were identified as areas of interest. These areas include connected automated vehicles, mobile sensor systems, driver assistance systems, enhanced/next generation MDSS, “big data” platforms, data visualization, and video analytics. Use cases for each technology are detailed along with recommendations for potential deployments in both near term and over a five-year planning horizon.

This project gathered information about available Global Positioning Systems/Automatic Vehicle Location (GPS/AVL) equipment and vendors to gain an understanding of their use by state and local agencies for winter maintenance activities. Depending on the complexity desired, many tools and equipment can comprise these systems, including truck controllers, data collection devices, communication devices, plow sensors, and software. This equipment allows agencies to better manage and analyze their winter maintenance operations. There are also numerous choices agencies have in what GPS/AVL solutions to employ, as well as how to effectively use them. The project included four main tasks: conducting a national search of available literature about winter maintenance GPS/AVL solutions, equipment, and technology, developing a survey for state and local agencies to collect data on their experiences with GPS/AVL systems, developing an equipment guide about GPS/AVL equipment based on the literature search and survey results, and developing a synthesis of policies focused on issues and considerations relating to the implementation of GPS/AVL technology for winter maintenance. The following report documents the process of completing the four tasks and the findings on GPS/AVL equipment and vendors.

Mobile RWIS technologies are still relatively new to the market, with only a few early-adopting agencies deploying them, primarily in testing situations. This study provides a comprehensive and comparative analysis of four commercially available mobile RWIS sensors. The sensors in the study include: Lufft’s MARWIS, Teconer’s RCM411, High Sierra’s Mobile IceSight, and Vaisala’s DSP310. Testing was completed in two phases. Phase I focused on the accuracy of different sensor parameters when compared to a known baseline. These tests took place at the MnROAD testing facility, a test track containing a variety of pavement types operated by the Minnesota Department of Transportation. Phase II was conducted in “real-world” settings on active roadways. Sensors measured the environment along a set route in live traffic in a variety of weather conditions. The study compared the sensors’ performance while measuring air temperature, surface temperature, relative humidity, surface condition, water film thickness, and friction. The evaluation also compared qualitative aspects of the sensors such as installation methods. The project found that overall, sensors performed similarly across all parameters. This report ranks sensors by accuracy, but the absolute differences in values used to determine rank are often very small. The study also developed standardized recommendations for various mobile sensor parameters. While differences across sensors and the high variability in their readings make establishing universal standards difficult, some commonalties were found. The report includes a suggested matrix of a few basic levels categorizing grip, surface state, and mobility impact. Project completed for Clear Roads Pooled Fund program, #TPF-5(353).

SRF Consulting Group worked with MnDOT in identifying specific uses for the remote sensing tools; a list of potential tools was generated; MnDOT reviewed and then developed a short list of five tools which SRF then investigated. This Transportation Research Synthesis presents the findings including information on tool applications and details for MnDOT's specific application including pros and cons of each.

MnDOT maintains nearly 400 dynamic message signs (DMS) along the state's highways. The Regional Transportation Management Center displays real-time messages to warn motorists of congestion, roadwork or an incident ahead that could be hazardous or cause a delay. DMS use to convey weather alerts has been limited to manually-entered blizzard alerts and other very isolated winter conditions. MnDOT has been concerned about the timeliness of weather messages and the chance that such messages could be overused, possibly leading motorists to take them less seriously. To make winter road weather alerts most effective, researchers developed a software interface to acquire weather alerts from the National Weather Service's system and translate them into text messages for DMS. The system selects the appropriate DMS locations and posts the alert message until it expires. Operators can return to manually posting or removing alerts at any time. MnDOT intends to begin using this system for blizzard and snow squall alerts. The automatic option for DMS messages will enhance the timeliness and accuracy of DMS alerts for severe weather and allow RTMC operators to attend to other work.