Monthly Archives: August 2011


UDOT launched the annual statewide “Walk More in Four” challenge today.

UDOT's Student Neighborhood Access Program is a comprehensive safe walking and biking to school program that engages and educates students, parents, school administrators, crossing guards and communities.

During September, students can practice safe walking and biking for a chance to earn money for their school and bikes and scooters for themselves. This year, the school with the highest percentage of students participating will win $500 to be used by its safety committee.

Walk More in Four encourages all Utah K-8 students to walk or bike to school at least three days each week during the four weeks in September leading up to International Walk to School Day, Wednesday, Oct. 5, 2011. Schools must register for the competition by September 7.

The Walk More in Four Challenge is part of the Student Neighborhood Access Program. To encourage safe walking and biking, SNAP provides free resources, including mapping software, a 35-minute musical assembly and DVD, student activity booklets and teacher lesson plans, to assist in getting more students walking and biking safely to school. For more information about the Walk More in Four Challenge or SNAP, visit the website or call Utah’s Safe Routes to School Coordinator, Cherissa Wood, at (801) 965-4486.


New guidance devices are popping up on the side of state roads.

Steel post delineators are difficult to repair and usually need to be replaced. The white delineator in the background has a post that rebounds, even after several vehicle hits.

Delineators are devices with retroreflectors that are installed along roadways to provide guidance to drivers at night and during other low visibility conditions. “On dark and stormy nights, sometimes all you can see are those delineators,” says Lynn Bernhard, Maintenance Methods Engineer for UDOT.  It’s important to keep the devices in good working condition, he explains.

Traditional post-mounted delineators, made of galvanized steel with attached retroreflectors, are ubiquitous in Utah.  The delineators are prone to frequent vehicle hits on some state roads, so up-keep can be a challenge. When a post is badly bent, workers sometimes try to use brute strength to put it upright again, but usually, the post needs to be replaced. A few types of flexible posts have been tried without good success – some tend to shatter when hit in cold weather.

In those high-hit areas, UDOT is transitioning to using a new type of post that can withstand nearly ten times as many vehicle hits as traditional steel posts. The new posts are made of durable recycled plastic with a joint at the base that allows the post to rebound after a vehicle hit.

State Route 68 north of Eureka served as one of the test areas for the new posts. The narrow stretch of road serves vehicles towing trailers heading to nearby the Little Sahara recreation area. With a total of about 300 posts, workers were replacing about 800 a year. Test results show that the new posts will save material and man hour costs over the long run, even at three-times the cost of steel posts. The new devices also improve work-place risk, since fewer service calls are required. The amount of waste requiring disposal is also reduced.

“I think they’re very worth while,” says Chad Allinson, Eureka Maintenance Station Supervisor. He is quick to thank Bernhard for helping obtain the new devices. Allinson has found that the posts usually rebound after a hit, but the ones that get pushed over are easier to fix than the steel post delineators.

Another high-hit area, Provo Canyon, will get the new posts soon. Check back next week to read about how the new delineators, along with several other safety measures will improve winter operations on the winding, high mountain road.


Transportation officials and stakeholders from four western states will collaborate to improve mobility on I-15.

Created with Admarket’s flickrSLiDR.

I-15 Mobility Alliance: a combined effort to keep people, goods, services and information moving along the crucial interstate corridor.

A crucial interstate corridor for trade and travel

The I-15 Mobility Alliance is one of several groups that have formed across the nation to collaborate on regional transportation goals. A similar group, the I-95 Corridor Coalition, formed in the 1990s to cooperate to clear freeway incidents that slow traffic flow then later broadened its mission to include mobility goals.

Corridor coalitions enjoy “success not otherwise available,” according to an article on the FHWA website.  Joining forces “builds a strong, authoritative institutional framework” that can successfully secure funding for ambitious projects.  I-15 Mobility Alliance members are seeking a similar path. “We’re looking at something fairly significant,” John Thomas, UDOT Director of Planning. He cites the I-95 Corridor Coalition as an example of how to build consensus, credibility and political clout.

One region, one corridor, one vision

The Nevada Department of Transportation started the effort in July to form a regional vision and then take action. Thomas believes it’s a very forward-thinking approach. NDOT officials “have a good understanding of how things outside their border can influence their system.”

“Critical connectivity is the foundation of the discussion,” says Dan Andersen, a Transportation Planner with CH2M HILL. The alliance includes mega-regions with separate identities but “we’re joined at the hip.” Since each state has issues that impact other states, “we really depend on each other.”

Even Arizona, with just a small portion of the freeway, plays a key role.  I-15 crosses the Virgin River Gorge in the north-west corner of the state, and soon, aging bridges will need to be replaced. Without those bridges, the detour is huge with a delay cost to match.

UDOT is contributing an important tool to the effort: uPlan – a user-friendly, online, GIS based application that displays data spatially and allows users to build customized maps. More than just a repository of information, uPlan is a great medium for collaboration.

Seeing the big picture

Alliance members are taking an expansive view that includes the whole transportation environment, not just the roadway.  Ports, rail, aviation, trucking, multimodal transportation and even information flow will be considered in the mix of options for improving mobility. The holistic approach will require participation from a wide range of stakeholders, so group membership is open-ended.

The group is working on an assessment of needs and setting preliminary priorities. Leaders of the alliance met this week to work on a master plan that articulates the need for solutions and defines the group’s mission. The document will be presented for endorsement at the AASHTO Annual Meeting in October.


Some Utah bridges built before World War II are eligible for inclusion in the National Register of Historic Places.

UDOT recently completed a survey of pre-war bridges. The survey report will be combined with a previous survey of post-war bridges completed last year to provide an important resource that UDOT project teams can use during environmental, planning, design and construction phases of transportation projects.  The complete report is on   UDOT’s website and will be available at the Lester Wire Library soon.

This bridge at the mouth of Little Cottonwood Canyon is recommended as eligible for inclusion on the National Register of Historic Places based on its rare type and artistic value. See images of the other bridges below.

Along with an inventory of bridges and their features and locations, the report also includes a rich and interesting historical context.  Themes and trends in bridge design and roadway development “and how those trends were manifest in Utah,” is detailed in the report, explains Elizabeth Giraud, Architectural Historian at UDOT.  Examples of some pre-war themes include detailing how new technologies and materials were adopted into design and how federal legislation and economic conditions, like the Great Depression, affected the development of the transportation system.

Pre-war statewide priorities were promoted by the Utah State Road Commission, UDOT’s predecessor.  Formed in 1909, the USRC “focused on adding more grade separated roads, improving road surfaces, connecting to state boundaries and providing access to state scenic resources in the southern part of the state,” says Giraud.

The historical review draws on a variety of sources including Utah State Road Commission meeting notes and design manuals, planning studies, the UDOT bridge inspection inventory, historic state maps,  and the book that should always be within arm’s reach here at UDOT – Knowlton’s History of Highway Development in Utah. The historical background in the survey is really worth reading for anyone in the transportation industry. Knowing about past trends and innovations can foster a better understanding of present construction and design.

A detailed inventory form for each bridge was completed during the survey process. Inventory forms list bridge location and UDOT Region, dimensions, distinctive features such as variation on a given bridge type, and whether or not the bridge qualifies for inclusion on the National Register of Historic Places.

The bridges were determined to be NRHP eligible under criterion A and C of the rules for the National Register. To qualify under criterion A requires details about how the property functioned during an historic event or time period. To qualify under criterion C requires information about the distinctive type or aesthetic value of the property.  Bridges that are “works of the master” also qualify under criterion C.

UDOT will now partner with the Utah State Historic Preservation Office to establish a programmatic agreement concerning the findings. Eventually, the information can be added to the in the bridge so it can be easily accessed.


  • 210 Pre war bridges were surveyed, 42 were determined to be eligible for the National Register of Historic Places
  • 409 Post war bridges were surveyed, 34 were determined to be eligible for the National Register of Historic Places
  • Only non-interstate UDOT bridges were inventoried
  • No bridges built prior to 1909 were found
  • Elizabeth Giraud is the Project Manager for the study which was conducted by Mead and Hunt.

The slideshow below shows some of the bridges that were identified by Mead and Hunt as eligible for the NRHP. Click on the large images to see captions.

Created with Admarket’s flickrSLiDR.


UDOT is looking for ways to improve the visibility of pavement markings at night during rain storms.

Small glass beads applied to paint make pavement markings shine at night. As vehicle headlights illuminate the road, each bead acts as a tiny retro-reflector that bounces light back to the source. Collectively, the beads make pavement markings highly visible for drivers. That is, until rain covers the road, creating a shiny surface that interferes with the retro-reflective quality of the beads.

A double drop system applies paint and two different bead types.

Maintenance Planning Engineer Ken Berg and Region 2 Pavement Marking Coordinator Dan Betts are testing three different wet-night beads to see which one is the best retro-reflector. The test is a follow-up to work Betts has done to improve wet-night visibility and durability of pavement markings.

Betts’ method uses two different bead types – UDOT’s standard plain bead and a wet-reflective bead applied in equal proportion. Both are retro-reflective above and under water, but the wet-reflective bead is larger and has a “higher reflective index,” says Betts, making it better at reflecting light through water. Using two bead types “gives us the best of both worlds,” with good dry and wet retro-reflectivity.

To improve durability, the markings are placed in grooved pavement. Grooving the pavement slightly, about the thickness of a quarter, keeps the lane markings from being scraped off by snowplows and significantly improves life of the markings by six to eight times.

Soon, Berg and Betts will test three wet-reflective beads, all with different compositions, to see which one performs best during storms at night. Testing will be conducted on three contiguous 3500 foot sections on eastbound Bangerter Highway (SR 154) between Redwood Road and I-15. The close proximity of the test areas provides “a good comparison under similar if not exact conditions,” says Berg.

Pavement markings for the test were placed last week. On each test section, a different wet-night bead was applied in equal proportion with UDOT’s standard bead. All markings were applied on grooved pavement using the same method.

Next step: data collection

Both subjective and objective data will be collected. During storms, Berg or Betts will drive the sections, video tape and record field notes about any observable, subjective differences among the test sections. Collecting objective data is a two-person operation. A van with an attached retroreflectometer will be used to measure and quantify the reflectivity of the markings. Data sent to a lap-top inside the van will let testers see and compare measurements immediately.

[youtube tmHKQ8nciTM]

The retroreflectometer measures by scanning across the marking, taking in some pavement on either side. A variety of information is produced, including a graph that provides a quick visual interpretation of the measurements. The software integrated with the retroreflectometer allows the user to choose from a variety of collection options. For example, upper and lower retro-reflectivity threshold values can be set for a pass-fail test.

By fall of this year, Berg and Betts expect to have preliminary results to share with others at UDOT and the larger transportation community. Testing will continue for two to three years, and the results will be used to select a cost effective safety improvement for road users.

More about UDOT’s pavement marking operations:

  • The retroreflectometer measures light in millicandelas per lux per meter squared.
  • Markings are applied using a double drop system that allows two types of beads to be dropped simultaneously on newly applied paint.
  • For maintenance operations, UDOT uses water-based paint for pavement markings, which is 5 to 10 percent the cost of durable pavement markings, such as tape. Recessing the paint stripes below the surface of the pavement can help the markings last up to eight times longer than surface applied paint.
  • UDOT Maintenance technitions can operate the pavement marking equipment, which saves time and conserves funding.



A new guide will help UDOT project teams make prudent decisions that maximize system-wide benefits.

UDOT's Practical Design Guide helps team members work together to meet project objectives.

The Practical Design Guide effectively supports UDOT’s Final Four Strategic Goals to Take Care of What We Have, Make the System Work Better, Improve Safety and Increase Capacity.

The core purpose of the guide is to “optimize the money we’re spending,” according to Jesse Sweeten who managed development of the guide. “It’s not just a money saving method…it’s a concept to optimize the system.” Spending carefully means that UDOT can save funding and build more projects, resulting in system-wide benefits to traffic mobility, safety and connectivity.

People who are familiar with how UDOT works will recognize the concepts. “We’ve been doing this for a long time,” says Sweeten. The guide is an overview of best practices that breaks down the roles and responsibilities of project teams and managers from design through construction.

“Any investment above the point of diminishing returns is an inefficient use of resources that would yield higher returns if invested elsewhere” – UDOT Practical Design Guide

Allocating limited project resources is challenging but doable. Starting with a comprehensive, well defined objective statement is the first step. To be useful, the objective statement should be developed by the project sponsor and be concise using commonly understood terms and an accurately and carefully worded description of the intended outcome. The project team can then evaluate improvements against how they line up with the objective. Project improvements should be limited to those that meet the objectives without going over.

Success depends on cooperation among the Utah Transportation Commission, the project sponsor, multi-disciplinary project teams and the UDOT Operations group (responsible for long term maintenance). The guide lists the responsibilities of each group and stresses keeping lines of communication open, collaborating, using good engineering judgment and maintaining flexibility.

Keeping engineering standards high

Achieving project objectives can sometimes involve obtaining approval for exceptions, deviations or waivers when appropriate – UDOT grants exceptions only when safety and mobility are not harmed. Some common examples of exceptions include reduced shoulder paving, deck replacement instead of bridge replacement, pavement rehabilitation instead of full replacement, reduced pavement thickness and narrower lane width.

The new Design Guide promotes tried and true methods that can help UDOT teams meet project objectives, eliminate over-design costs and save project funding for other projects or additional improvements.


This post highlights UDOT’s ThrU-Turn intersection – want to know more about construction impacts? Attend the ThrU-Turn Open House on Monday, August 15 from 4 to 7 p.m. at Draper City Hall Council Chambers, 1020 East Pioneer Road (12400 South). Construction starts this week with completion scheduled for late 2011.  Project Hotline: 888-914-5454. Send an email to for weekly updates.

An intersection type that’s new to Utah will soon reduce delay and improve safety through a busy Draper business district.

[youtube BsY9PHFpZE0]

Utah’s first ThrU-Turn Intersection will be built at 12300 South and State Street. UDOT has adapted a Michigan U-Turn, commonly built from scratch in the mid-west, in an innovative retrofit improvement that will upgrade the safety and function of the busy intersection. The TTI will provide significant relief from traffic delay on the first day of operation and well past 20 years, according to UDOT traffic studies.

Wait-times at the intersection are causing congestion and concern. Future traffic demand projections show that by 2030, crippling delay will cause traffic to spill onto surrounding streets. Without improvement, motorists will eventually avoid the area altogether or just pass through as a commuter – not good news for an urban business center.

The TTI is an excellent solution to future congestion that comes with an impressive cost-benefit analysis. The budget is relatively small at just under $5 million. During the first year of operation, road users will save almost $1 million–a lot of user-cost savings for the money spent.*

The TTI re-routes left turns

Instead of turning left at the intersection, motorists will proceed through and make a U-turn at a designated turning point, wait briefly at a signal before going straight, then turn right. Turning areas are designed for commercial trucks, so vehicles will be able navigate easily. Even though left-turners will be traveling out-of-direction for a short distance, traffic modeling shows that left turn travel times will still be reduced. “People make U-turns all the time when intersections are too busy…here it’s engineered for safety, efficiency and convenience,” says Adan Carillo, Public Involvement Manager at UDOT Region Two.

More safety, less delay

Safety is top priority for UDOT. Moving left turns away from intersections will reduce the number and severity of crashes.

The TTI is close to freeway exits where traffic tends to weave, increasing the likelihood of crashes. Adding medians and improving traffic flow will also improve safety. The TTI design lets motorists move safely around medians to access business. Since traffic congestion will be reduced, motorists coming from the freeway will have more time and space to safely change lanes.

The TTI’s efficiency is all in the signal timing. Eliminating two protected left turn phases from the signal cycle improves efficiency by moving more traffic through the intersection. A two-phase signal cycle can easily be coordinated with signals, keeping traffic progressing through the rest of the corridor.

Driver friendly

UDOT has given a lot of time and thought to signs and lane markings in the area. The TTI logo shows the traffic path, and the signs are big enough to be seen easily but not so big as to be obtrusive. Lane markings also show the traffic path. Public information efforts will focus on teaching the public how to drive the TTI. Law enforcement is on board too – during the first few days of operation, police officers will hand out instructive flyers instead of citations when people break traffic rules.

The TTI is a cost effective solution that reduces delay while carefully considering the needs of the local community.

When investigating solutions, UDOT looked for a cost-effective way to improve traffic flow with minimal inconvenience to business owners. UDOT’s design team considered a CFI and some grade-separated alternatives; those options would have helped traffic but at a high cost to tax payers. The TTI effectively reduces delay, and the minimal widening areas needed are away from the intersection where utilities and signal poles won’t be disturbed.

One great way to reduce inconvenience to business and road users is to limit project duration. Construction for the TTI will be quick and easy because the project requires minor road widening, new signals and striping. Just a few months of minimal impacts will deliver better traffic flow by the end of the year.

*Savings to road users is calculated by identifying the average cost of delay to road users, then comparing delay reduction to a “do-nothing” scenario.

The Thru-Turn Project Team:

Peter Tang, Project Manager, UDOT

Marwan Farah, Resident Engineer, UDOT

Adan Carillo, Public Involvement Coordinator, UDOT

Mel Bodily, Traffic Engineer, Avenue Consultants

Dan Young, Project Manager, PEC

Marc Bennett, Design, PEC

April Gordon, Public Involvement Manager, Jacques and Associates


Guest post: Thank you, Andrew Johnson former employee of the UDOT Traffic Operation Center, for contributing this informative overview about how stormwater is managed. Great post! StormTrap provided the construction image below and information for this article.

How Stormwater Management Mitigates Flood Damage

With summer winding down, Utah’s flood control experts are indicating this year’s flood season may soon be coming to an end. That’s good news to hear, although officials will continue to monitor the snow pack on some of the highest elevations.

This is an example of stormwater infiltration, where a retention system recharges the water back into the soil as it filters the runoff.

At ground level, we all know rain travels down the gutter to disappear underground. To many, stormwater management is a term that doesn’t mean much, unless they’re seeing the consequences of heavy rain or increased melting snow.

During a storm, a number of things take place. In warmer months, rain will collect on roads and sidewalks, and be directed into gutters. In parking lots, as well as residential and commercial developments, the water will follow the grade of the pavement or landscaping, and be funneled into an underground basin.

There are two types of vessels commonly used: retention and detention basins. A retention basin takes the collected water and provides an infiltration surface to recharge the water into the soil. This limits the contaminants entering the ground below. A detention basin is similar, but simply collects the runoff and releases it in a controlled rate.

Utah certainly saw the destructive nature of water in action this year, especially during the spring and summer months of 2011. But how did the beehive state fare compared with 2010? Roland Steadham is the chief meteorologist for KTVX-TV, a television station based in Salt Lake City, and tells me that we pulled out of this year’s flood season fairly well thanks to mitigation and stormwater management. “Some may say that the state hydrologists and the media were ‘crying wolf’. This is a case where the wolf was there, we just put up a fence to keep him out.” That proverbial “fence” came in the form of sandbags, according to Steadham, but also the effective mitigation efforts of Utah’s emergency management plan. For any possible natural disaster, there’s a response plan in place, and part of that plan includes efforts to collect, detain and disperse water in a controlled manner. That’s stormwater management in action.

According to the Federal Emergency Management Agency, FEMA, flooding is the most frequent severe weather threat across the country, and 90% of America’s natural disasters involve flooding. One component of the Agency is The Flood Insurance and Mitigation Administration, designed to handle flood insurance, flood hazard mapping and floodplain management. By recognizing which areas of the state are prone to flooding, and effectively managing the geographic floodplains, mitigation takes place. But identifying needs is only a fraction of the complete mitigation effort. When designing Utah’s transportation systems, for example, civil engineers plan for the elements by incorporating specific materials into the pavement or concrete surface of the road, adjusting the grade, and collecting the rain and melting snow in an underground detention basin.

Cameras allow TOC operators and meteorologists to monitor roadways 24-7

The topography of the Wasatch Front poses a unique challenge for stormwater management. Since a majority of the population lives and works in the valley, collecting the water from melting snowpacks in the mountains, and releasing it in a controlled rate is key to preventing widespread flooding during the warmer months of the year. “…in one second, Little Cottonwood Creek at its peak transported approximately 60,000 pounds of water. Do the math; in one day one this creek transported over 5-Billion pounds of water. That’s a lot of wrecking balls,” Steadham points out.

Keeping the runoff away from the streets and highways is also important. That’s why many of Utah’s roads and freeways are equipped with cameras, which are monitored 24 hours a day, 7 days a week from the Traffic Operations Center. There’s also a staff of meteorologists at the TOC, who develop specialized forecasts for UDOT’s road maintenance crews and snowplow operators. If a band of heavy rain moves through a particular area, UDOT can pinpoint the location, monitor the road surfaces for standing water, and dispatch a crew to the site if needed.


UDOT has received a coveted national award for developing a cutting edge Geographic Information System based web application.

Frank Pisani, John Thomas, Jack Dangermond and Andrea Moser. Dangermond is the founder of the Environmental Systems Research Institute (Esri), and organization that focuses on developing web-GIS applications. Moser is a consultant with Bio-West, a environmental consulting firm. (See a list of team members below.)

UDOT has taken advantage of recent advances in web GIS and developed a user friendly, state of the art planning tool. uPlan, an online map that integrates data from many different sources, was recently recognized by Esri with a Special Achievement Award for as being in the top tier of web GIS applications in the United States. UDOT was one of only 100 to be recognized from a field of over 100,000 projects. “Getting this award indicates that UDOT is in-step with the world in employing the latest GIS technologies,” says John Thomas, Director of Planning at UDOT.

UDOT’s original goal was to build or find a data-sharing tool that could display information spatially. The project was started over four years ago after UDOT conducted an extensive review of available methods and tools. uPlan developers eventually combined two tools, the ArcGIS server and the Adobe Flex viewer.

Over the last two years, more data has been added and the application has been improved with customized widgets. The latest version includes live data from ePM, UDOT’s statewide online project tracking application. External agencies like planning organizations and utility companies have also contributed data. Soon, data owners will be able to upload data from a PC desktop.

The uPlan team was congratulated by UDOT Senior Team leaders in August 2011.

While providing access to data was the goal, better partnering has been an important outcome. “We are approaching the ability to display and eventually analyze nearly any type of business data,” says Thomas. uPlan encourages broad participation in the planning process by presenting data in an easy to  understand format and allowing and encouraging participants to bring their own information to the table.”

New advances in technology lets UDOT put information in the hands of many users where previously, only GIS analysts had access.  With about one hour of training, users can easily learn to “build a custom map in minutes,” says Thomas, by simply clicking boxes. And, data silos can be combined and viewed together to allow for better collaboration among agencies. For example, users can view future UDOT projects along with planned utility improvements to see potential conflicts. Automated functions within uPlan allow users to get detailed reports and fact sheets that pull and format data from different databases.

Congratulations, uPlan Development Team!

Frank Pisani, UDOT GIS Specialist

Tom Twedt, Bio-West, Consultant Project Manager

Andrea Moser, Bio-West, GIS Specialist/Technologist

April Brough, Bio-West, GIS Specialist

Stephen Lawe, RSG, System Architecture

Spencer Jenkins, AGRC, Governance

Bert Granberg, AGRC, GIS Specialist

Bryce Lovell, RSG, Developer

John Thomas, UDOT, Project Manager


Today’s post is second in a series about traffic signals. Missed the first post? See it here.

Did you know that the first traffic signal was invented in Salt Lake City?

The device looked like a bird house and was controlled by a police officer on the side of the road. Today’s signals are equipped with detectors, computerized timing and variable phases. And the signal controller is a computer or a live person watching from a Traffic Operations Center miles away.

A young man poses by Lester Wire's first traffic signal. (Used by permission, Utah State Historical Society, all rights reserved.)

Modern innovations have helped traffic engineers manage traffic flow and reduce delay. Still, there are a lot of factors to consider when it comes to achieving orderly progression from signal to signal:

Directional traffic volume – Most UDOT roads are not busy all the time. Very heavy traffic volume often occurs only during morning and evening commutes. The most efficient way to deal with high volume directional traffic is to provide more green light time for commuters.

For roads that are busy outside of the standard morning and evening commute, other solutions, such as a CFI, dual left turn lanes or a Thru-Turn may be a good option when signal timing alone won’t help. UDOT will implement Flex Lanes on 5400 South in Taylorsville this year. 5400 South experiences heavy traffic volume during the morning or evening commute with very little to no delay the rest of the time.

Traffic patterns change – A variety of detection devices are used to see traffic and adjust the signal phases to accommodate traffic flow. “Modern signals are capable of detecting vehicles and pedestrians and can change based on actual traffic demand,” says Luker. Devices are usually mounted on signal arms or buried under or in the pavement.

Sometimes, timing needs to be adjusted to fit current traffic patterns. Many people call UDOT to report signals that seem to need attention. “In the city, almost everyone encounters traffic signals on a daily basis. If signals are not operating correctly, it causes delay and frustration, and often minor, inexpensive improvements can have a big impact.”

Detection can help signals work efficiently, especially on major arterial streets. “By having detection, the signal may see that there are no cars at the intersection in a particular direction,” says Luker. During the next cycle, the green phase can be made longer. “This is more efficient overall, because green lights aren’t being wasted, but if you are on a minor street you’ll have to stop more often.”

Special event traffic – Sports events or concerts can cause delay on an otherwise efficient roadway. Fortunately, most such events happen outside of the rush hour on evenings or weekends. TOC signal operators can anticipate events, like college football games, adjust the signals to give more green light time at the start or end of the event. While the event traffic is occurring, signal operators can observe traffic and make real time adjustments to expedite traffic flow.

Dual right turn lanes on east bound 9000 South – road users who take I-15 to the game get some extra help getting through the intersection. During normal traffic, the dual lane designation is off.

At State Street and 9000 South in Sandy, just north of the Soccer Stadium, variable lanes allow dual right turns when needed.

Allowing for transit vehicles – Trax Lines in Salt Lake County and the BRT in West Valley City require traffic engineers to make adjustments to signals to make the transit vehicles move efficiently along with automobiles. Signals on transit corridors are often timed to give priority to transit so the fewest number of people possible are inconvenienced. When train cars or busses reach an intersection, the phase order is interrupted to allow the transit vehicle to progress through the signal. After the transit proceeds, the signal plays catch-up.

Moving more people

UDOT is working hard to reduce traffic delay by making the current system work more efficiently and by increasing capacity where appropriate. The goal when it comes to signal timing is to move more people, not just vehicles.  Individual drivers can also make choices that can help save time, use less energy and reduce traffic congestion. Visit the TravelWise website to investigate some effective strategies like trip-chaining and alternative work schedules.