Utah Study Tested Vehicle-to-Everything Technology in the Field to Determine How Snowplow Operations Could Benefit.
Salt Lake City, Utah, United States
Analysis Of Using V2X DSRC-Equipped Snowplows To Request Signal Preemption
Summary Information
Vehicle-to-everything (V2X) technology allows vehicles to communicate with other vehicles and transportation infrastructure around them. This study evaluated how V2X technology could improve snowplow operations in the Salt Lake City, Utah metropolitan area. A field test was conducted in the 2019-2020 winter season to determine how signal preemption could benefit snowplows based on V2X systems using dedicated short-range communications (DSRC). In five corridors throughout the Salt Lake City metro area, roadsides units (RSUs) were deployed to measure traffic signal, snowplow and vehicle efficiency impacts. Both V2X-equipped routes and similar non-equipped routes were analyzed to ensure the technology impacts could be properly measured.
METHODOLOGY
The study consisted of a field test over the months of October 2019 to March 2020 along five V2X-equipped corridors in the Salt Lake City metropolitan area. Data was collected during and immediately following snowstorms. Besides DSRC data, weather data and traffic signal data from automated traffic signal performance measures (ATSPM) was also collected to measure how the V2X technology was working, and specifically the duration of preemption. Vehicle performance data was collected to measure the speed of the snowplows as well as that of general traffic on each corridor. This also allowed for the collection of crash data to determine any safety impacts of the study. Message logs and signal controller log datasets were later used to analyze the results of the field test. Each corridor was matched with a similar non-equipped corridor where data was also collected during the same hours. Observational comparisons and statistical analysis were performed to evaluate the system at both the daily level and time of day.
FINDINGS
- Preemption was granted more than 80 percent of the time when requested by snowplows.
- Snowplows requested preemption over 50 percent of the time when approaching an intersection.
- Signal controller phasing was affected for an average of five minutes after preemption was granted.
- Traffic on V2X-equipped routes traveled at speeds closer to the speed limit than routes not equipped with V2X technology.
- There was a decrease in roadway crash rates with V2X technology than roads without it. Between the snow season of 2018-2019 and 2019-2020, most of the equipped routes had a larger reduction in roadway crash rate (up to 3.87) than their not-equipped counterparts (1.82).
- There was also a decrease in roadway crash severity with V2X technology than roads without it. For example, no injury/property damage only events were reduced by 22 percent for equipped routes comparing 2019-2020 snow season to 2018-2019 snow season, while the same type of crashes increased by 7 percent for not-equipped routes.
- Snowplows stopped fewer times from requesting and being granted preemption.
