2019 Road Weather Management Performance Measures Update

Appendix B: Findings by Measure

ROAD WEATHER MANAGEMENT PROGRAM PERFORMANCE AND RESULTS

Objective 1: Build and sustain relationships with multidisciplinary partners to expand road weather management deployments.

Table 25. Summary of Objective #1 Performance Measures

PM #1: Number of agencies participating in road weather R&D projects
25 State DOTs are currently participating in the Pathfinder project, including 7 new States. 15 public agencies have participated in the development and use of the Road Weather Management (RWM) Capability Maturity Framework (CMF). 27 State DOTs have participated in the Integrated Mobile Observations (IMO) program, including 3 new States. 21 State DOTs have participated in or contributed to weather data environment research. There is no data on how many State DOTs have been involved in vehicle-to-infrastructure (V2I) implementation activities. Two States currently use the Integrated Modeling for Road Condition Prediction (IMRCP) tool. A total of 43 States are conducting at least one road weather management activity, up from 41 in the prior period.
PM #2: Number of agencies participating in and benefiting from Road Weather Management stakeholder meetings/workshops
The number of State DOTs attending the annual Road Weather Management stakeholder meetings increased to 29 in 2017 and 2018. The Every Day Counts-5 (EDC-5) Summits held in 2018 were well-attended, with 48 states participating in 1 of the 5 events held around the country.

Objective 2: Ensure that road weather management investments improve highway performance.

Table 26. Summary of Objective #2 Performance Measures

PM #3: Number of agencies that collect and report road weather-related performance measures to the public (winter severity index, mobility index, etc.)
Among the State DOTs surveyed, 24 DOTs reported regularly collecting and reporting some form of road weather performance measures. 12 DOTs reported they did not collect and report road weather performance measures, and another 3 were uncertain. This is a positive trend over the prior period in which 22 DOTs reported collecting, 13 reported not collecting, and four (4) were uncertain about collecting road weather performance measures. 18 State DOTs reported using a winter severity index to compare agency road weather management performance across events or years. This is 2 additional agencies utilizing such a tool over the prior period.
PM #4: Number of agencies that have a process for evaluating the return on investment (ROI) or net benefit of their road weather management investments
Only 4 State DOTs reported having a process in place to evaluate ROI or net benefits of road weather management investments, down from 9 State DOTs in the prior period.
PM #5: Reductions in agency costs of weather-related maintenance and operations activities
While local government expenditures for snow and ice removal remained relatively constant in 2014, 2015, and 2016 (most recent data available), State government expenditures for snow and ice removal spiked by 46.7% in 2014. State government expenditures decreased in 2015 by 11.8%, but still remained above total local government expenditures. 2014 and 2015 are the first 2 years in which State government expenditures exceeded local government expenditures for snow and ice removal.11 Total expenditures increased 24.1% from 2013 to 2014 and decreased 6.1% from 2014 to 2015. State government expenditures for snow and ice removal decreased by 16.0% from 2015 to 2016, bringing State government expenditures below local government expenditures again. The relatively constant rate of local government expenditures means total expenditures decreased by 8.5% from 2015 to 2016. The above observations represent the natural, unpredictable variation in weather and road weather conditions over a short observation period. A majority of States saw expenditures increase in 2014, but the most significant (over 100% increase from 2013 expenditures) were in Arkansas, Delaware, Georgia, Louisiana, Maryland, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, and Texas. The Kentucky Transportation Center utilized GIS to optimize snowplow routes. The models were able to eliminate the need for 9 snowplows in 4 counties, which was an estimated annual $225,000 in savings.12
PM #6: Reduction in number and types of fatalities and crashes attributed to adverse weather nationally
The annual percentage of fatal crashes that occur during inclement weather has remained between 10% and 11% since 2005. Currently available data suggests that the annual percentage of fatal crashes occurring during inclement weather could be as low as 9%, however a number of fatal crashes remain uncharacterized in terms of weather conditions. The fatal crash rate during inclement weather per thousand licensed drivers peaked in 2003-2004 at 0.024 crashes per thousand licensed drivers. That rate has steadily decreased to between 0.014 and 0.016 crashes per thousand licensed drivers for the period 2009-2017.
PM #7: Reductions in extent of capacity losses and delays due to fog, snow, and ice events including freight
Virginia DOT implemented a variable speed limit system to combat reduced visibility associated with fog events on the I-77 corridor in Fancy Gap by reducing travel speeds on the corridor when fog was present. Prior to the installation, driver speeds remained relatively constant with non-fog conditions. After the installation, VDOT found that drivers were willing to reduce speeds to the posted level, and that the reduction in speed within the corridor did not have a significant impact on travel into or out of the corridor.13
PM #8: Increase in travel time reliability or decrease in variability due to road weather management strategies during adverse weather
Few agencies currently track the impacts of road weather management strategies on travel time reliability. A 2018 study found that drivers were less likely to reduce their travel speed or following distance in foggy conditions compared to rainy conditions. The study suggested agencies integrate new language into dynamic messaging systems and implement variable speed limit strategies in corridors prone to fog-related accidents.14
PM #9: Reduction in number of tons of salt or chemical usage in the U.S. normalized by winter severity index
2015 and 2016 (most recent years data is available) saw decreases in gross salt consumption over the prior year by 7% and 11%, respectively. However, the explanation of the variation may be unclear because the data is not normalized by winter severity.

Objective 3: Transportation, weather, and research communities use and rely on fixed and mobile road weather observations.

Table 27. Summary of Objective #3 Performance Measures

PM #10: Number of State DOTs participating in MADIS program
5 new States have a signed MADIS data sharing agreement, but 13 have dropped out of the program, according to the State DOT survey.
PM #11: Number of State DOTs that subscribe to road weather products and services
The use of agency sensors (RWIS and IMO), agency field personnel, and the MADIS system has remained relatively constant compared to the prior period. Significantly more states are using information from the public (including social media) and FAA products, with 29.4% and 16% increases over the prior reporting period. Twice as many States subscribe to U.S. Geological Survey earthquake alerts than during the previous period (8 States in 2019 versus 4 States in 2017). Use of National Weather Service products dipped 10.4% compared to the previous reporting period.
PM #12: Number of State DOTs collecting mobile observations of road weather data from vehicle fleets
More than three-quarters of State DOTs collect mobile observations from their vehicle fleets. Of the 39 State DOTs surveyed, 30 (76.9%) reported collecting real-time field data from maintenance vehicles. This is up from 23 State DOTs from the prior period (57.5%). Agencies reported plow status and material usage data as the most collected type of data, with 16 States reporting they collect more than 50% of their data from maintenance vehicles. 15 agencies reported more than 50% of Atmospheric Weather data and 12 agencies reported more than 50% of their Road Weather Conditions data coming from maintenance vehicles. Compared to the 2017 survey, there was an overall increase in the number of States reporting that they collect at least 25% of their real-time field data from plow status and material usage, atmospheric weather data (e.g., air temperature, relative humidity), and road weather conditions data (e.g., pavement temperature).
PM #13: Number of State DOTs reporting the use of Environmental Sensor Stations (ESS) in operations and maintenance activities
Respondents to the State DOT survey reported a total 2,610 ESS, which is an increase over previous years. The primary use of ESS data is to support traffic management and maintenance decision-making, with over 92% of respondents indicating their agency used ESS data for this purpose. This finding is an increase over the prior period but returns to the level observed in the 2015 update. 21 State DOTs reported using ESS data to provide current conditions to traveler information systems. This is down from 28 State DOTs that reported doing the same in the prior period. Over the past three updates to the RWMP, there has been a downward trend in the percentage of agencies using ESS data as an input for segment-level forecasts: 2015 (57.9%); 2017 (50.0%); and 2019 (42.1%).

Objective 4: Advance the state of the art for mobile sensing and integrating vehicle data into road weather applications.

Table 28. Summary of Objective #4 Performance Measures

PM #14: Number of/percentage of responding agencies using mobile data-based applications in road weather management
16 State DOTs have developed applications or tools to use data generated by vehicle-to-infrastructure or infrastructure-to-vehicle connectivity. This is up from just 7 in the prior update. Another 17 State DOTs are considering, but have not yet developed, similar applications or tools.

Objective 5: Advance the state of the practice by promoting tailored management strategies for different regions.

Table 29. Summary of Objective #5 Performance Measures

PM #15: Number of states disseminating advisory weather and road weather information to travelers
The percentage of agencies deploying dynamic message signs to convey atmospheric weather information has increased from 63.2% in the prior period to 71.8% in the current period. However, a smaller percentage of agencies (42.1% in prior period; 28.2% in current period) are reporting a full statewide deployment. The percentage of agencies deploying road condition information statewide on dynamic message signs and on highway advisory radio has continually increased over the past three reporting periods, and currently sits at 59.0% and 48.7%, respectively. When including partial deployment, these percentages rise to 97.4% and 89.7%, respectively. A smaller percentage of agencies are using social media to disseminate information to travelers on road weather conditions. The percentage of agencies disseminating road conditions via agency-hosted websites or 511 phone systems has remained relatively constant with the prior period.
PM #16: Number of agencies using control and treatment strategies during weather events
Traffic incident management continues to be the most widely deployed strategy, with 89.7% of State DOTs reporting partial or statewide deployment. The second most common strategy is lane/road closures and traffic diversions, with 70.3% of agencies deploying partially or statewide. The partial or statewide deployment for temporary vehicle restrictions, variable speed limits, traffic signal timing, and ramp metering are 37.8%, 36.8%, 23.1%, and 21.1% respectively. A 2017 study found that signal optimization strategies at arterial-level intersections with moderate levels of demand could help reduce delay during winter weather events.15
PM #17: Number of agencies that coordinate with their local forecast offices for road weather management and operations
All State DOT survey respondents reported at least some coordination with the local National Weather Service forecast office. The number of agencies reporting routine coordination with meteorological experts to provide products and information to assist in decision-making rose from 55.0% in the prior period to 71.8% in the current one. An additional 20.5% of respondents to the survey noted they were beginning to work with local NWS offices on all major events.

Objective 6: Weather-related decision support technologies are integrated into traffic operations and maintenance procedures

Table 30. Summary of Objective #6 Performance Measures

PM #18: Number of agencies adopting MDSS technologies and methods
The percentage of State DOTs with a statewide MDSS deployment for snow and ice control increased from 20.0% in the prior reporting period to 33.3% in the current one. The percentage of State DOTs reporting a limited MDSS deployment decreased from 15.0% in the prior reporting period to 12.8% in the current one. The percentage of agencies that do not currently have an MDSS for snow and ice control but reported a need for one decreased from 22.5% in the prior period to 17.9% in the current one. The percentage of agencies reporting no need for an MDSS also decreased from 35.0% in the prior update to 28.2% in the current one.
PM #19: Number of agencies using other weather-related decision support tools
Respondents to the State DOT survey indicated an overall decrease in the use of weather-related decision support tools for road weather management, and 15.4% of States reported not using any tools. Providing traveler information continues to be the most-used tool; however, there is a downward trend in the percentage of agencies using this tool. Respondents reported using two tools, support of non-winter maintenance activities and coordination with other jurisdictions/agencies, at levels comparable to the prior update (43.6% and 53.8%, respectively). Respondents reported an increase in the use of decision support tools for traffic control/management and setting seasonal load restrictions.
PM #20: Number of agencies reporting use of appropriate analysis tools to factor weather impacts and strategies
A significant majority of State DOTs responding to the survey (83.8%) reported either they did not use or were not aware of whether their agency used weather-responsive analysis tools or models. This is a decrease from the prior period, in which 95.0% of agencies reported the same. Traffic signal optimization tools are the most frequently used by State DOTs, with 13.5% of survey respondents indicating their agency used some form of this tool. Just one agency reported using sketch-planning analysis and travel demand analysis tools. Just one agency reported using macroscopic, mesoscopic, and microscopic simulation tools.

Objective 7: Advance the state of the practice by raising road weather capabilities and awareness across the transportation and weather community.

Table 31. Summary of Objective #7 Performance Measures

PM #21: Number of agencies and attendees who have taken any of the sponsored RWMP training courses and workshops
The RWMP supported 26 workshops in 2017 and 28 workshops in 2018 on topics including: cost/benefit analyses; Pikalert® implementation, transportation system resilience in the context of adverse weather, weather-responsive traffic management, weather-savvy roads (EDC-4), weather-responsive management strategies (EDC-5), RWM Capability Maturity Framework, Pathfinder initiative, Integrated Mobile Observations (IMO), connected and autonomous vehicles, and business processes for road weather operations.
PM #22: Number of agencies and participants in road weather management webinars led by the RWMP
The RWMP supported a total of 13 webinars in 2017 and 17 webinars in 2018 on topics including: effective weather messaging, transportation system resilience in the context of adverse weather, connected and autonomous vehicles, weather-savvy roads (EDC-4), and weather-responsive management strategies (EDC-5).
PM #23: Number of agencies that have participated in or conducted road weather management capability maturity assessment exercises
16 States have conducted the capability maturity assessment workshops, and 4 additional States have indicated interest.
PM #24: Number of meetings, site visits, or venues where road weather management presentations/briefings were made
Between January 2017 and March 2019, RWM program staff or support contractors attended or facilitated at least 137 conferences, meetings, peer exchanges, etc. The total number of participants at these events is estimated at over 9,400.

Objective 8: Operations community is engaged with weather resiliency and sustainability communities.

Table 32. Summary of Objective #8 Performance Measures

PM #25: Number of agencies conducting vulnerability/risk assessments or developing/implementing resiliency plans, for their RWM infrastructure and processes to respond to extreme weather

One-quarter (25.0%) of agencies responding to the State DOT survey indicated they had conducted a vulnerability or risk assessment for RWM infrastructure. 27.8% of agencies reported developing or implementing resiliency plans for RWM infrastructure. Nearly half of all respondents (47.2%) reported their agency as having developed or implemented a process for responding to extreme weather. 22.2% of State DOTs have participated in resilience adaptation planning activities. Only 11.1% of agencies reported no participation in the development of adaptation practices.