Tag Archives: traffic signals

A google doodle with a Utah link

Whether you’re sitting at a red light or passing through on green, the traffic signal is one invention that revolutionized the world. And because of that, Google has taken to honor the anniversary of the first installation with a “doodle”.

August 5, 2015's Google Doodle

August 5, 2015’s Google Doodle

On August 5, 1914, the first traffic light was installed in Cleveland, Ohio, on the corner of 59th and Euclid. With 20,000 cars being sold per month in 1914, and horse-drawn wagons, street cars, and carts still in play, city streets in America were woefully congested, and a need arose for traffic management. Police used to stand in the middle of intersections and wave their arms to control traffic, and just before the turn of the century, England tried a gas-lit stoplight, but they had a tendency to explode.

But what does that have to do with Utah?

One of the solutions to the traffic management problem came when Lester Wire — a Salt Lake City policeman — created a traffic light out of a hand-made wooden box that had red and green lights whose wires were attached to light wires above. Right in the Beehive State, a solution was born. 

This replica of Lester Wire's first traffic light greets visitors to the UDOT Traffic Operations Center.

This replica of Lester Wire’s first traffic light greets visitors to the UDOT Traffic Operations Center.

We’ve come a long way since 1914, and UDOT is proud of what our employees at the Traffic Operations Center have done to create a state-of-the-art traffic management system. Instead of mechanical lights and wooden boxes, we use sophisticated computers that gather traffic and weather data to manage 60% of the 1,927 traffic lights statewide. We use that information to give you the best data, sent right to your smart phone, and we also have one of the few in-house DOT weather rooms, staffed with two full-time meteorologists and 8 weather professionals.

Next time you’re sitting at a red light or passing through on a green light, you can thank a fellow Utahn for coming up with a traffic solution. Thank you, Google, for giving us a chance to walk down memory lane!

First yellow flashing right turn arrow arrives in Utah

LEHI — Northern Utah County is developing at a rapid pace, emerging as a new frontier of the high-tech industry. In addition to retail attractions such as Cabela’s and the Outlets at Traverse Mountain, the area around I-15 at Timpanogos Highway (SR-92) has been dubbed the “Silicon Slopes,” attracting businesses who want affordable office space, a reliable talent pool from area universities and the high quality of life Utahns enjoy with a variety of outdoor recreation options just minutes away.

With all this development, UDOT continually evaluates how to improve traffic flow through the I-15/SR-92 interchange.

The latest update to the interchange is also a first in Utah: crews installed the state’s first flashing yellow right turn arrow at the northbound I-15 off-ramp to eastbound SR-92 in Lehi. You have probably driven through dozens of flashing yellow left turn arrows, where turning traffic yields but may make a left if there is no oncoming traffic. So why does the flashing yellow right turn arrow work at this interchange?

A flashing yellow arrow on a right hand turn on SR-92 allows traffic to flow more freely in a fast-growing part of Utah County.

A flashing yellow arrow on a right hand turn on SR-92 allows traffic to flow more freely in a fast-growing part of Utah County.


“The right turn goes into a lane that takes people to the SR-92 commuter lane, but a lot of people want to make a left into Adobe or Cabela’s,” said UDOT Region Three Signal Engineer Adam Lough. “We were seeing traffic back up and drivers getting frustrated because people who wanted to cross traffic to get to the left lane would be stopped on a green light. The flashing yellow signals a yield condition for drivers who want to move to the left lane on SR-92 as well as for the queue of traffic on the ramp.”

Now when the light is green, there is no eastbound traffic for drivers to weave through to move left; and during the flashing yellow, drivers who want to move left must wait for a safe opening in the traffic flow. Drivers who want to access the SR-92 commuter lanes from the I-15 northbound off-ramp still get impatient at times, but Lough said the flashing yellow right turn arrow has improved the traffic flow. “This provides a safer condition and has reduced the amount of backing on the ramp.”

Lough developed the idea of using a flashing yellow right turn arrow to address the traffic problems at this interchange ramp. Although UDOT had never installed anything like it, Lough suggested that it would be the best solution and worked with Traffic Operations Center staff to implement it. So far, he is pleased with the results.

“I am always looking for better ways to do things,” he said. “It is rewarding to see how changes like this make people’s commute a little better.”

Lough said the signal is almost always green or flashing yellow, but it briefly turns solid yellow and red as part of the signal’s cycle. The pedestrian button also triggers the red arrow.

“There is quite a bit of pedestrian traffic between the employment centers and retail outlets on either side of I-15 in this area,” Lough said. “Drivers really need to be on the lookout for pedestrians and bicyclists moving through this interchange.”

UDOT Signal Engineering Team receives Governor’s Award for Excellence

Photo of team members standing with Governor Herbert.

Team members with Governor Herbert. From left to right: Shane Marshall, Mark Taylor, Carrie Jacobson, Shane Johnson, Governor Herbert, Rob Clayton, Derek Lowe, Jamie Mackey, Peter Jager and Matt Luker.

For the last three years UDOT’s traffic signal management team has been focused on bringing innovative solutions to Utahns. The team was recently recognized by receiving the Governor’s Award for Excellence from Governor Gary Herbert.

The signal management team has been working on in-house solutions to better track and time traffic signals across the state. UDOT worked with the Indiana Department of Transportation and Purdue University to create software that provides real time traffic information to UDOT. The program was then developed by UDOT and the Department of Technology Services (DTS) and is a web based Automated Traffic Signal Performance Measurement System (SPMs).

SPMs are a series of visual aids that display high-resolution traffic data from vehicle sensors and traffic signal controllers (intersection computers changing the traffic signals) that help agencies effectively manage traffic signals in ways that improve mobility, increase safety, reduce vehicle emissions, preserve pavement infrastructure and use resources more effectively. In most cases on UDOT state roadways, SPMs are accomplished utilizing the same vehicle sensors already deployed at signalized intersections for normal day-to-day operations without the necessity of having to install expensive new equipment or sensors.

The sensors allow analysis of data collected 24-hours a day, 7-days a week (not just during business hours), and provide a clear framework for performance analysis and decision-making. The transportation community uses SPMs to directly measure what they previously could only estimate and model.

The use of the real time and accurate information helps traffic signal engineers make better decisions on signal timing and traffic patterns. Bangerter Highway is a good example of how accurate information helps move traffic. The SPMs were able to increase the amount of cars that reached the intersections at a green light by 19%. The information has also helped with moving large amounts of traffic during one time or recurring special events.

All of this information helps commuters stay on the move, saving them time and money. The cost for this program and the cost of a traffic signal change is very low compared to the amount of travel savings day by day.

In an effort to help traffic around the state UDOT has shared this technology with counties and cities so that they can better understand and monitor their traffic signals. UDOT hopes that the SPM’s will help them to get a more comprehensive idea of their traffic patterns and signal accordingly.

Mark Taylor a Traffic Signal Operations Engineer said “Innovations, creativity, risk and increased transparency are necessary to meet UDOT’s needs.  Automated performance traffic measures allows us to optimize mobility, increase safety and use resources more efficiently.”

UDOT’s goal is to continually refine the use of technology in traffic signals and timing in the future. They are always looking for ways to improve their efficiency and their ultimate goal of keeping Utah moving.

This guest post was written by Adam McMillan, Traffic Operations Center Intern.

Highlights from the 2013 Annual Efficiencies Report

Efficiencies within UDOT often generate cost savings for the public and the Department through better utilization of resources and innovative technologies. At the end of each year, UDOT prepares an efficiencies report which summarizes key efficiency initiatives from the year. The annual report fulfills a requirement for UDOT to describe the efficiencies and significant accomplishments achieved during the past year to the State Legislature. UDOT Senior Leaders use the report in presentations during legislative committee meetings.

Following are the key efficiency initiatives summarized in the FY 2013 report:

  • Bicycle Detection and Pavement Markings
  • Flashing Yellow Arrow for Left Turns
  • Reflectorized Yellow Tape on Signal-Head Back Plates
  • Portable Weather Station for Advance Warning of Debris Flows
  • Audio Over IP Highway Advisory Radio in Utah County
  • Commercial Vehicle Bypass (PrePass)
  • Partnered Fiber-Optic Cable Installations
  • Resolving Utility Conflicts through a Preserve and Protect Approach
  • Utah Prairie Dog Programmatic Agreement
  • Performance-Driven Programming
  • Energy-Efficient LED Lighting Upgrades in Department Facilities
  • iMAP GIS Tool
  • Improved Decision Making Using Mobile Data Collection
  • MMQA Data Collection Teams
Photo of a flashing yellow signal

Flashing Yellow Arrow left-turn phasing

One example from the 2013 report is the improved safety at intersections that are changed from Protected/Permissive to Flashing Yellow Arrow left-turn phasing. UDOT and other jurisdictions throughout Utah are among the first in the nation to implement flashing left-turn arrows. Potential annual public cost savings per installation ranges from $17,745 to $2,769,000 from reduced crashes.

Photo of rock and mud covering the highway

Debris flow across S.R. 31 in Huntington Canyon

Another example from 2013 is the use of a portable weather station to provide advance warning of debris flows and flooding at the Seeley burn scar near S.R. 31 in Huntington Canyon. Using the station contributed to over-all safety, minimized equipment losses, reduced response time, and minimized impact to commerce. An estimated $50,000 was saved through reduced risk to field crews, motorists, and equipment.

UDOT Research Division staff coordinate each year with UDOT Senior Leaders and the Communications Office to collect and compile write-ups on the past year’s key efficiency initiatives. This process will start again in August for FY 2014. We look forward to receiving “game changing” efficiency topics from all Regions and Groups that will potentially be included in the annual report.

The 2013 and earlier annual reports are available online at www.udot.utah.gov/go/efficiencies.

This guest post was written by David Stevens, P.E., Research Project Manager, and was originally published in the Research Newsletter.

Region Three Traffic Signal Update nearly Complete

Photo of the State Street and 1320 South intersection in Provo

New signals at Provo State Street and 1320 South.

Existing traffic signals have been updated to newer equipment that includes controllers that send real-time data about the signal operations to the Traffic Operations Center.

With the upgraded controllers, UDOT can troubleshoot issues remotely such as noticing a stuck pedestrian button or verifying signal timing.

Traffic engineers can track data that used to require manual labor such as traffic speeds, traffic volumes and percent arrival on green.

Photo of the inside of a signal cabinet

A signal cabinet at State Street and 1320 South. The cabinet contains a controller that gathers and transmits real-time traffic data for remote analysis and optimization of the system.

Out of 249 signals operated by UDOT in Region Three, 211 have been upgraded to gather this real-time traffic data for analysis and optimization of the system. “Small adjustments can sometimes make a big difference for our traffic operations,” said
Adam Lough, Region Three Engineering Manager.

“The upgraded signal controllers allow us to make these adjustments and monitor how the intersection is operating without being on-site.”

WASHTO Quality Award Winners

I am pleased to announce that the WASHTO Quality Award winners for 2013 are the Ogden Canyon Fiber Project and Traffic Signal Operations teams. It became evident as our selection committee reviewed the nominations that these two groups distinguished themselves as leaders who have made significant contributions to the Department while simultaneously improving the quality of life in our communities.

Photo of Carlos Braceras and the Ogden Canyon Fiber Project Team

UDOT Executive Director and the Ogden Canyon Fiber Project Team

The Ogden Canyon Fiber Project Team members were Jesse Glidden, Lynne Yocom, Blaine Leonard, Brent DeYoung, Rex Harris, Matthew Smith, and Dave Moss.

As many of you know, Ogden Canyon (S.R. 39) is a narrow, winding 5-mile canyon road connecting the Ogden Valley with the metropolitan area. It is a critical transportation link but a difficult location for constructing projects due to its mountainous terrain.

Our Region 1 folks initially had asked our Traffic Management Division to install a VMS sign in the canyon that would warn motorists of frequent winter canyon closures. Lynn, Blaine and Matt were more than happy to do that but while they were visiting the site they noticed construction already happening in the Canyon.

Ogden City had recently started the installation of a waterline. The team knew that underground construction of this magnitude in the canyon rarely occurred. They successfully seized upon this opportunity to partner with the city and get a fiber communications line installed along the entire canyon corridor.

This vital link to Ogden Valley now provides fiber optic communications for traffic monitoring and public communications. In addition, Ogden City enjoys a fiber connection to their water treatment plant and residents have improved cell and broadband service.

Because our team members took the time to think beyond the limited scope of their own individual duties, they were able to see the bigger picture. This synergistic approach to finding a solution will benefit thousands of people for decades to come.

I commend them for their great work.

Photo of Carlos Braceras and the Automatic Signal Performance Measures Team

UDOT Executive Director and the Automatic Signal Performance Measures Team

The first place winning team is our Traffic Signal Operations group, consisting of Mark Taylor, Jamie Mackey, Matt Luker, Shane Johnson, Derek Lowe, Peter Jager, Eric Rasband, Adam Lough and Carrie Jacobson.

Tasked with providing “World-Class” signals operations and maintenance, our folks have risen to the occasion. Adopting best practices from our partners at Indiana DOT, they have developed eight different performance measures currently available for 750 intersections. The measures provide both real-time and historical data, with all of the information housed on the UDOT Traffic website.

The program works via FTP connections located throughout the network that provide information to our traffic signal controllers. Every 15 minutes TOC servers retrieve and store “packets” of time-stamped data. This process is overseen by software engineers Shane Johnson and Derek Lowe. Anyone can access this data, which is an approach that fosters transparency and information sharing. Because of their efforts, UDOT is now the national leader in real-time traffic signal performance measures.

It’s not hard to see why in June of this year UDOT received the AASHTO Technology Implementation Group (TIG) award for their efforts in this area. But this team isn’t stopping there. By the end of the year they plan to have additional performance measures to track elements such as historical travel times for arterials and overall operations system improvements.

Both teams’ efforts have served to further our Department’s Strategic Direction.

Our Ogden Canyon Fiber Team has strengthened the economy by providing fiber optic service to Ogden City’s water treatment plant and improved cell and broadband service to residents. They have optimized mobility via a vital communications link that will facilitate traffic management and public information. They have improved safety with the capability to more effectively manage traffic, thus keeping drivers safer and getting us one step closer to our goal of Zero Fatalities.

Our Traffic Signal Operations team has strengthened the economy by improving the efficiency of the signal system. This has made a huge impact on alleviating traffic congestion and consequently the movement of goods and services throughout the state. In addition, they have implemented signal timing plans to accommodate large events such as college football games and community parades.

The signals team has optimized mobility by closely monitoring and adjusting red and green time to allow for better progression along corridors. They have improved safety by partnering with our radar vendor to track approaching vehicle speeds at intersections. To preserve our infrastructure, they have devised a way to quickly find and replace deficient vehicle detectors.

These efforts do not go unnoticed. Congratulations to both teams for their exemplary work and dedication. Please join me in thanking them for their great work as they are well-deserving of the 2013 WASHTO Quality Awards.

Information about all of the WASHTO Quality Awards nominees is available in a previous post.

Traffic Signal Performance Measures announced as a 2013 AASHTO Innovation Initiative

Engineer Mark Taylor working in an open traffic signal cabinet

Engineer Mark Taylor working in a traffic signal cabinet.

Managing traffic is an effective way to reduce congestion, save fuel costs and improve safety. One of the most visible components of the traffic management landscape is traffic signals. Day-to-day traffic challenges keep the staff at the UDOT Traffic Operations Center (TOC) very busy- especially during winter weather, special events and during the morning and evening commutes. The operators at the TOC have the ability to remotely operate nearly 80% of Utah’s traffic signals, which can be a very helpful way to alleviate traffic congestion. Each signalized intersection has a metal cabinet adjacent to the intersection that holds the equipment needed to operate the traffic signals. The equipment that operates the traffic signal can be programmed for specific traffic patterns along a corridor in an effort to better manage traffic.

Every year, the American Association of State and Highway Transportation Officials (AASHTO) identifies innovative projects that have been successfully adopted by transportation agencies across the country. One of the 2013 AASHTO Innovation Initiatives was UDOT’s Traffic Signal Automated Performance Measures program. The program developed a structure that will allow UDOT to actively manage, in real-time, its traffic signal systems which will help traffic flow as efficiently as possible along any given roadway corridor. “When we have a maximum number of vehicles arriving at a traffic signal when the light is green, traveler delay is minimized,” said Mark Taylor, UDOT’s Traffic Signal Engineer. Other benefits to well-timed traffic signals are reduction in vehicle emissions and reduction in crashes. Since traffic management needs to occur every day of the week and at all times of day, the Performance Measures program helps to monitor and improve traffic flow even when a traffic signal engineer is not available.

UDOT is moving forward with an AASHTO Technology Implementation Group (TIG) which will work to document the techniques, benefits and technologies UDOT is using for Traffic Signal Performance Measures so other interested transportation agencies can begin their own program in this important area. More information about the AASHTO Innovation Initiatives selected for 2013 can be found on their website.

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.

UDOT assists with traffic management for Draper Sergeant Derek Johnson’s funeral procession

Photo of the funeral processon on I-215

The beginning of Sgt. Johnson’s funeral procession on I-215.

On September 1, 2013, Utah lost Draper Police Sergeant Derek Johnson in the line of duty. This tragic loss brings grief and heartfelt sadness, but also patriotism, gratitude and remembrance from whole communities. Nearly 4000 law enforcement, family and citizens joined the memorial service at the Maverik Center and tens of thousands of thankful citizens lined the procession route.

UDOT’s Traffic Management Division collaborated with many law enforcement agencies to ensure that traffic flow to and from the Maverik Center and along the procession route moved as smoothly as possible. UDOT’s traffic signal operations staff were deployed to key intersections throughout the Salt Lake Valley to assist with traffic control, while UDOT’s Traveler Information Manager was using the @UDOTTraffic

Photo of wall of images from the Traffic Operations Center

Staff at the Traffic Operations Center monitored the procession route on cameras throughout the Salt Lake valley.

Twitter account to update the public on lane and ramp closures. UDOT was listening to the police radio event channels to monitor the traffic flow along the procession route.

Photo of flags along and citizens lined up along 12300 South.

Citizens lined up along 12300 South in Draper to honor Sergeant Johnson. Photo courtesy of Mark Taylor.

UDOT worked with the Unified Police Department, Unified Fire Department, Salt Lake City Police, Draper Police, the Utah Department of Emergency Management and the Utah Highway Patrol for traffic management during the funeral and procession. Several other agencies not mentioned here came together honor Sgt. Johnson – an awesome tribute to a dedicated public servant.

Optimizing Mobility – UDOT’s Traffic Management Division

TOC Control RoomThe UDOT Traffic Management Division (TMD) houses UDOT’s Traffic Operations Center (TOC), the traffic signal management division, traveler information program and deployment and maintenance for Utah’s robust Intelligent Transportation System (ITS) network. UDOT utilizes the resources from within the TMD to plan for and react to any type of event that reduces capacity on Utah interstate and highway routes.

The UDOT TOC is operated 24 hours a day, 7 days a week, 365 days a year! TOC operators actively monitor traffic, looking for road debris, crashes or lane closures due to construction. This sophisticated ITS network includes traffic cameras, overhead message signs, vehicle detectors and much more. The fiber optic network that connects the ITS devices to the TOC provides an excellent, fast connection that allows TOC operators to react at a moment’s notice. “Our TOC operators monitor traffic throughout the state from our facility in Salt Lake City. If a crash occurs in St. George, our operators are able to use traffic cameras to locate the incident and post a message warning motorists on an overhead message sign within a matter of seconds,” said Mike Evans, Control Room Manager.

In addition to day-to-day traffic problems, the UDOT TMD also provides traffic signal support for large-scale special events. A signal management operator can remotely control nearly 80% of UDOT’s traffic signals from the TOC.

UDOT’s Traffic Management Division is charged with operating a smart transportation network. Using technology to help manage traffic is an excellent way to optimize mobility, reduce delay and increase roadway capacity. To schedule a tour of the UDOT Traffic Operations Center, please call(801) 887-3710.