Tag Archives: winter weather

UDOT app wins award for digital pioneering

SALT LAKE CITY — The pioneering sprit has always been in Utah’s blood. From the Winchester rifle, Word Perfect and wider Pioneer Streets, to the Roadometer and Television, Utah has always tried to be at the forefront of technology.

In the digital age, the Utah Department of Transportation (UDOT) has continued as a technological pioneer, especially in the field of Intelligent Transport Systems (ITS). It was recently awarded a “Best of ITS” award by the ITS World Congress this fall for its Citizen Reporter app, which was piloted during the 2012-2013 winter season.

Citizen Report Screenshot

A screenshot of the Citizen Report app

The app, which is the first of its kind in the United States, is aimed at Keeping Utah Moving, specifically during winter months. It allows citizen volunteers to report on road weather conditions along specific roadways across the Beehive State, after a short training session. These reports give enhanced road weather information to travelers when the stakes are the highest — during inclement weather. 

In large, sparsely populated states like Utah, state DOTs have trouble providing up-to-the-minute accuracy on road conditions to travelers. It’s especially tough in Utah, where nearly 1,000 cameras statewide still can’t see every inch of roadway. But that’s where crowd sourcing from citizen reporters comes in, providing more accurate and timely information to the traveling public on conditions around the state.

Lisa Miller, UDOT’s Traveler Information Manager, said the program was extremely successful, with over 1100 reports last year from approximately 500 reporters. She predicts four times the usage of the app this coming year.

“Our early concern was that the data might not be reliable,” Miller said. “But what we’ve found is that the incoming data is 99% accurate.”

Other states, such as Idaho, Iowa, Kentucky, Michigan, Montana, Nebraska and North Dakota have requested information from UDOT to create similar programs in those states. The success of the program has spurred the department to produce another app, called Click N Fix, which allows the public to report potholes, burnt out highway lights, and other safety issues. The app will be more widely available to the public in early 2015.

The 2014 ITS World Congress

UDOT was awarded a “Best of ITS” award for “Best New Innovative Practice” in September.

“Crowd-sourcing is emerging as an effective means to both engage and serve the public, Miller said. “The public can now make more informed travel decisions, which impacts everything: safety, mobility, and the economy.”

To become a Citizen Reporter:

In order to become a UDOT Citizen Reporter, you will need to complete a brief training (either online or in person), take a short quiz and complete a sign-up form. The training takes approximately 10 minutes to complete. Once a volunteer has completed these steps, they will be provided with a login and PIN, and can begin submitting reports. Reports are submitted through the UDOT Citizen Reporting app, downloadable for Android and Apple devices from the Apple App Store or Google Play Store.

If you would like to become a Citizen Reporter, please follow this link to take the online training: www.udottraffic.utah.gov/training/citizenreporter. For more information or to schedule an in person training, email UDOTCitizenReporter@utah.gov.

You can download the Citizen Reports app for your iPhone or Android device.

 

Comparison of Wintertime Asphalt and Concrete Pavement Surface Temperatures in Utah

Because winter maintenance is so costly, UDOT personnel asked researchers at Brigham Young University (BYU) to determine whether asphalt or concrete pavements require more winter maintenance. Differing thermal properties suggest that, for the same environmental conditions, asphalt and concrete pavements will have different temperature profiles. Climatological data from 22 environmental sensor stations (ESSs) near asphalt roads and nine ESSs near concrete roads were used to determine which pavement type has higher surface temperatures in winter.

Twelve continuous months of climatological data were acquired from the road weather information system operated by UDOT, and erroneous data were removed from the data set. In order to focus on the cold-weather pavement surface temperatures, a winter season was defined as the period from November through April, and the data were divided into time periods that were based on sunrise and sunset times to match the solar cycle.

To predict pavement surface temperature, a multiple linear regression was performed with input parameters of pavement type, time period, and air temperature. As shown in Table 1, the statistical analysis predicting pavement surface temperatures showed that, for near-freezing conditions, asphalt is better in the afternoon, and concrete is better for other times of the day. However, neither pavement type is better, on average, across the locations studied in this research. That is, asphalt and concrete are equally likely to collect snow or ice on their surfaces, and both pavements are expected to require equal amounts of winter maintenance, on average.

To supplement these analyses, which provided useful information about average pavement temperatures across the statewide pavement network, additional analyses of asphalt and concrete pavement surface temperatures were performed for a particular location in a mountainous region of northern Utah more typical of canyon areas. Asphalt and concrete pavement surface temperatures were directly compared at a location on U.S. Route 40 near Heber where asphalt and concrete meet end to end at the base of a mountain pass. As shown in Figure 1, an ESS was installed to facilitate monitoring of asphalt and concrete pavement surface temperatures, as well as selected climatic variables, at the site.

Data collected during the three winter seasons from 2009 to 2012 were analyzed in this research, and the same months and time periods used in the previous study were applied in this analysis as well. To compare the surface temperatures of the concrete and asphalt pavements during freezing conditions, multivariate regression analyses were performed. Equations were generated for three response variables, including the asphalt surface temperature, concrete surface temperature, and difference in temperatures between the asphalt and concrete surfaces.

The statistical models developed in the analyses show that the surface temperature of both asphalt and concrete pavement increases with increasing air temperature and decreases with increasing relative humidity and wind speed, and that the difference in pavement temperatures decreases with decreasing air temperature. For the studied site, the data indicate that concrete pavement will experience freezing before asphalt pavement for all time periods except late afternoon, when the pavement types are predicted to freeze at the same air temperature (see Table 2). Therefore, for material properties and environmental conditions similar to those evaluated at this U.S. 40 site, asphalt would require less winter maintenance, on average, than concrete.

Due to the interactions among albedo, specific heat, and thermal conductivity, the actual thermal behavior of a given pavement will depend on the material properties and environmental conditions specific to the site. As shown in this research, concrete pavement can be warmer than asphalt, which is typical of the statewide pavement network, on average, during late morning, evening, night, and early morning. However, the research also clearly shows that, in mountainous regions of northern Utah more typical of canyon areas, engineers may expect asphalt pavement to be warmer than concrete, or equal in temperature to it, during all time periods at sites that receive direct sun exposure, such as the one on U.S. Route 40 that was studied in this research. At such sites, selection of asphalt pavement may facilitate reduced winter maintenance costs; however, though statistically significant, relatively small differences in temperature between asphalt and concrete pavement surfaces may not warrant differences in actual winter maintenance practices. Other factors beyond pavement type, such as rutting and surface texture, may more strongly affect winter maintenance and should also be considered.

The results of the statewide comparison of wintertime temperatures of asphalt and concrete pavements, as well as the specific results for the U.S. 40 site near Heber, are detailed in two separate research reports available on the Research Division website.

This guest post was written by W. Spencer Guthrie, Ph.D., M.ASCE, Brigham Young University, and David Stevens, P.E., Research Program Manager, and was originally published in the Research Newsletter.

UDOT Citizen Reporter Program gathers volunteer data

Citizen Reporting LogoThe UDOT Citizen Reporting Program enlists volunteers to report on current road conditions along specific roadway segments across Utah. Since the program’s launch in November 2013, UDOT has received over 1,800 road condition reports on critical routes throughout the state. The accuracy rate of the reports continues to be very high, with only 0.03% of incoming reports determined to be inaccurate.

The long term goal of adding Citizen Reporters to UDOT’s weather operations road reporting is to supplement current condition reporting on segments where drivers are already traveling. The Citizen Reporter Program provides the traveling public with a conduit to report their observations directly to UDOT, saving time and money. UDOT employees also use the Citizen Reporting app to submit their reports.

Since the UDOT Citizen Reporter Program was launched volunteer reporters have submitted reports on 119 of the 145 road segments, helping to fill in gaps in locations where UDOT does not have traffic cameras or Road Weather Information System (RWIS) units.

Graph showing citizen reports by day. The most were received in Decemenger 2013.The volunteer reports are especially valuable during winter storms when conditions change rapidly. During a large winter storm that occurred in the beginning of December 2013, UDOT Citizen Reporters submitted over 130 reports, helping the traveling public as well as National Weather Service meteorologists and UDOT staff.

How do you become a UDOT Citizen Reporter?

In order to become a UDOT Citizen Reporter, you will need to complete a brief training (either online or in person), take a short quiz and complete a sign-up form. The training takes approximately 10 minutes to complete. Once a volunteer has completed these steps, they will be provided with a login and PIN, and can begin submitting reports. Reports are submitted through the UDOT Citizen Reporting app, downloadable for Android and Apple devices from the Apple App Store or Google Play Store.

If you would like to become a Citizen Reporter, please follow this link to take the online training: www.udottraffic.utah.gov/training/citizenreporter. For more information or to schedule an in person training, email UDOTCitizenReporter@utah.gov.

Variable Speed Limit Signs Now Activated on I-80

Photo of Variable Speed Limit sign with a semi passing by on I-80 in Parley's Canyon

Variable Speed Limit sign on I-80 in Parley’s Canyon

The UDOT Traffic Operations Center (TOC) now has a new tool to enhance safety for drivers  on I-80 – one of the most heavily-traveled roads in the state. Last Wednesday (Jan. 8), 15 new variable speed limit (VSL) signs were activated along I-80 in Parley’s Canyon. The new signs will be controlled by the TOC to help maintain consistent traffic flows and assist drivers in adjusting speeds when necessary due to weather conditions.

The 15 signs – 8 eastbound and 7 westbound, located between the mouth of the canyon and Jeremy Ranch, are equipped with LED display screens that allow UDOT to remotely adjust speeds. These adjustments will be made based on driver behavior and road conditions.

“We are always looking for new technologies to help us manage traffic more effectively and enhance safety,” said UDOT Region 2 East District Engineer Robert Miles. “These signs will help keep drivers moving and reduce the number of weather-related crashes in Parley’s Canyon.”

The variable speed limit signs in Parley’s Canyon have been divided into four zones – an eastbound lower zone and westbound lower zone, from the mouth of the canyon to Mountain Dell/Lambs Canyon, and an eastbound upper zone and westbound upper zone, from Mountain Dell/Lambs Canyon to Kimball Junction. When a speed limit is adjusted for a specific zone, the new speed limit will be displayed on all signs within the same zone. These zones were created because of the differences in weather patterns and average speeds observed in the canyon due to changes in elevation.

The TOC will monitor speed limits in the canyon. In the event of poor weather or low visibility, a traffic engineer will be able to review information such as current road conditions, weather forecasts, snowfall rates, observed speeds, and reports from maintenance personnel. Based on this information, the engineer can make the decision to reduce the speed limit as needed. Depending on conditions, speed limits may range from 35 to 65 miles per hour.

The new variable speed limit signs are the first of their kind in Utah. Other states, including Washington, Wyoming, Colorado and Nevada, currently use these signs and have observed a reduction in weather-related crashes in areas where these signs are employed. Washington (Snoqualmie Pass – I-90) and Wyoming (east of Evanston – I-80) in particular are using these signs in areas similar to Parley’s Canyon: interstate highways with moderate to heavy traffic, with significant elevation differences, that are prone to inclement weather.

The Parley’s Canyon VSL project was developed jointly by UDOT and the Utah Highway Patrol (UHP). The speed limits posted on these signs are not merely advisory speeds, but regulatory speed limits that will be enforced by UHP troopers.

I-80 in Parley’s Canyon was selected as the location for this pilot project due to its changing weather conditions, heavy traffic, and existing fiber optic communications network. The investment for the design and construction for the new signs was $750,000, and the annual operating expense is estimated between $7,500 and $10,000. UDOT is also considering installing variable speed limit signs in other locations around the state, such as Sardine Canyon and Provo Canyon, based on the results of this project.

This guest post was written by Aaron Mentzer with the UDOT Traffic team.

UDOT Launches a new Citizen Reporter Program

Diagram showing all of the different data sources for weather operationsCurrent and forecast weather conditions are a critical part of traveler information in Utah.  Utah has many high mountain passes and rural routes that frequently experience hazardous winter weather, and accurate road condition information for these routes is vital for traveler safety and route planning.

The UDOT Citizen Reporting Program enlists volunteers to report on current road conditions along specific roadway segments across Utah.  The volunteers can be UDOT employees, law enforcement, truck drivers, plow drivers, experienced commuters, or other volunteers.  The long term goal of adding Citizen Reporters to UDOT’s weather operations road reporting is to supplement current condition reporting on segments where drivers are already traveling.

All of the incoming data is compiled with carefully crafted logic to determine the condition of the road surface. Reports from plow drivers, law enforcement and other experienced reporters may be utilized in a different way than volunteer citizen data, however all data is immensely valuable and helpful in determining the condition of the road surface.

How do I become a UDOT Citizen Reporter?

In order to become a UDOT Citizen Reporter, you will need to complete a brief training (either online or in person), take a short quiz and complete a sign-up form. The training takes approximately 30 minutes. Once a volunteer has completed these steps, they will be provided with a login and PIN, and can begin submitting reports. Reports are submitted through the UDOT Citizen Reporting app, downloadable for Android and Apple devices from the Apple App Store or Google Play Store.

If you would like to become a Citizen Reporter, please follow this link to take the online training: www.udottraffic.utah.gov/training/citizenreporter. For more information or to schedule an in person training, email UDOTCitizenReporter@utah.gov.

Whatever the Weather

During storms, driving conditions can cause travel delay, especially during the morning and evening commute.

When a storm hits the Wasatch Front, a twenty-minute commute can turn into an hour due to slick roads, start-and-stop traffic and low visibility. What if traffic could be managed more effectively to minimize the sluggish traffic speeds drivers experience during storms?

Recent technological advances in assessing weather and controlling signals have given traffic engineers better tools to keep traffic moving in stormy weather. On some corridors along the Wasatch Front, UDOT is taking a Weather Responsive Traffic Management approach that puts the tools to use.

WRTM uses sensors, traffic signal plans designed for storm conditions, and sophisticated traffic monitoring systems already in place to move traffic more efficiently during winter weather.

Traffic on Riverdale Road PhotoDuring winter months in 2013, an urban arterial in northern Utah served as testing area for WRTM. Riverdale Road intersects a busy shopping district and connects four Utah cities with Interstates 15 and 84. Over 47 thousand vehicles travel the corridor each day.

UDOT’s results in managing Riverdale Road traffic during winter storms were very good – for motorists, that is. Drivers experienced less stopped time at intersections compared to other storm days, and overall, traffic speeds were not significantly impacted by weather.

Here’s how the WRTM system worked on Riverdale Road:

  • Traffic engineers created signal timing plans for implementation before or during a storm. The plans accommodate travel speeds that are likely during storms so that signalized intersections along the corridor work together to make traffic flow more efficient.
  • A Road Weather Information System unit was installed in the corridor. The RWIS helped meteorologists and engineers anticipate upcoming storm severity to decide which signal timing plan to employ.

    RWIS on Riverdale Road Photo

    RWIS on Riverdale Road

  • Detection units were installed overhead along the roadway. The new equipment is better at detecting traffic movement during storms, and the equipment gave UDOT traffic speeds.
  • To monitor traffic during storms, UDOT used a Signal Performance Metrics System that lets signal operators assess and adjust traffic in real-time. After a storm, the system can be used to evaluate how the signal plans worked.

Winter 2013 ended up being a challenging year to test the WRTM system. During testing, the Salt Lake City and Ogden area experienced one of the worst winter storms in the past decade. Nevertheless, post-storm review showed an average or above average improvement in performance in traffic operations in over half of the weather events, including during the major storm.

Post-storm analysis also shows that cars maintained a high level of progression from intersection to intersection with platoons of cars arriving on green lights. When platoons of cars arrive at intersections on green lights, traffic flow throughout the corridor is more efficient.

Based on the success of the Riverdale Road WRTM performance, UDOT plans to expand the system to other corridors.