To improve safety, roadway conditions, and motorist advisory warning information during winter weather, the Nevada DOT recently launched a pilot to test dedicated short-range communications (DSRC) to improve the collection of weather condition data from snowplow vehicle and roadside units along the I-580 corridor between Reno and Carson City, shown in Figure 20. The pilot is the third in a series of Integrated Mobile Observations (IMO) projects that Nevada DOT first launched in 2011. According to the FHWA, the IMO applications “promote the collection of mobile, weather, road, and vehicle data from agency fleets to improve situational awareness of road conditions.”[i] The application builds on a foundation Nevada DOT set with using Enhanced Digital Access Communications System radio for communication and cellular connectivity capabilities.
Project Purposes
In the Phase III snowplow connectivity project, roadside units, cellular signals, and on-board instruments are used by nine snowplow vehicles and one service patrol vehicle to provide real-time road and atmospheric condition data that will assist Nevada DOT’s Enhanced Maintenance Decision Support System (EMDSS) for roadway treatment. In addition to Nevada DOT’s internal use of the data, the information is used to inform the state’s 511 system and other traveler information software.
The flow of communication between the sensor equipment mounted in Nevada DOT’s vehicles and Nevada’s data exchange is illustrated in the graphic below. How does the information flow from the vehicle-mounted units to the state’s server and data exchange? As a first step, roadway and atmospheric weather conditions are read by sensor equipment in the vehicles. The sensor records the date, time, location, speed, altitude, air temperature, barometric pressure, humidity, dew point, road temperature, wiper status, and spread rate of treatment material. In the second step, the conditions report is relayed using cellular or roadside units that communicate with a central server.
Once the data is received by the Nevada IMO server, the server exports a CSV file. Data in the CSV file is then sorted through the Nevada Data Exchange where the information is shared with weather and road condition providers (e.g., Nevada 511, Waze). The data generated is also used by Nevada DOT for dynamic message signs, highway advisory radio messages, and the EMDSS.
The on-board vehicle sensors update conditions data every eight seconds. There are 18 DSRC systems locations along Nevada’s I-580 corridor between the I-80 interchange in Reno to 5th Street in Carson City, indicated in the map below. DSRC is used along I-580 and cellular coverage is used between the I-580 corridor and Lake Tahoe. DSRC has an effective range of 300 meters (less than one-quarter mile) at highway speeds, which can lead to longer caching times and delays in information exchange. In areas where DSRC, Wi-Fi, and cellular are not available, data is stored on the vehicle until communications are reestablished.[ii]
Nevada’s Integrated Mobile Operations system meets the standards of the National Transportation Communications for Intelligent Transportation Systems Protocol (NTCIP), Society of Automobile Engineers (SAE), and the National Marine Electronics Association (NMEA)—all incorporated through the Institute of Transportation Engineers (ITE) utilizing the Traffic Management Data Dictionary (TMDD). This TMDD data standard provides rules for communicating and vocabulary needed to permit electronic traffic control equipment from different manufacturers to operate with each other.
Outcomes
Even though the primary purpose of the snowplow data collection is to inform the state’s operations and maintenance practices, other users who benefit from the data are cities and counties, Nevada DOT’s 511 system, the www.nvroads.com website, the Nevada Highway Patrol, and WAZE. This IMO project has been integrated with the National Center for Atmospheric Research and FHWA’s Weather Data Environment.
Nevada DOT staff stated that the technology has helped to standardize how operations staff are trained for weather-related road treatment—important in an environment where staff turnover requires training for new employees.[iii]
Resources
Stakeholders involved in the technology applications and development include the University of Nevada-Reno, University of Nevada-Las Vegas, University of California-Davis, and the Desert Research Institute. The cost of implementing the Phase III snowplow sensor project was over $4,000 for each vehicle. The initial roadside equipment (i.e., radio and GPS/weather sensor) cost over $5,500 but was paid for during earlier phases of the Nevada project. In addition to one-time capital costs, the project has recurring data plan costs of $15 – $35 per month per vehicle. Additional information about costs and lessons learned are available in the Nevada DOT’s Integrated Mobile Observations 3 Final Project Report prepared for the U.S. DOT.[iv]
[i] Pisano, P. (2019). Are Your Roads Weather Savvy? FHWA Research and Technology, https://www.fhwa.dot.gov/publications/publicroads/19spring/03.cfm
[ii] FHWA (nd). Weather-Savvy Roads – Leveraging Multiple Communications Systems for Vehicle-Based Data Sharing: Nevada Department of Transportation Case Study, https://ops.fhwa.dot.gov/publications/fhwahop18030/fhwahop18030.pdf
[iii] Nevada DOT (2019). Presentation at 2019 NADO Annual Training Conference
[iv] U.S. DOT (2018). Nevada DOT’s Integrated Mobile Observations 3 Project Final Report, https://collaboration.fhwa.dot.gov/dot/fhwa/RWMX/Documents/Nevada%20DOT%20IMO%203%20Final%20Report.pdf
This report was delivered to the U.S. Department of Transportation in 2020. It was primarily authored by NADO Program Manager Rachel Beyerle and NADO Associate Director Carrie Kissel. Many transportation agency staff and others assisted with this project in a variety of ways. We offer deep and heartfelt thanks to all the individuals who have provided information and images, consented to be interviewed, and offered editorial guidance in support of this research. This work is supported by the U.S. Department of Transportation under requisition number HOIT190194PR. Any opinions, findings and conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of U.S. DOT or the NADO Research Foundation.
To read more about the report that contained this and other case studies, follow this link.
