A Diverging Diamond Interchange and Auxiliary Lane project will improve mobility and safety at the Bangerter Highway, SR-201 intersection.

The DDI intersection made its Utah debut in American Fork with the  Pioneer Crossing project. Now, UDOT is using the innovative design to improve traffic flow at Bangerter Highway and SR-201.

In addition to the DDI, the project will also add a traffic lane between Bangerter Highway and I-215, dual right-turn lanes onto the SR-201 eastbound on-ramp, dual northbound left-turn lanes on Bangerter highway at 1820 South and dual eastbound left-turn lanes at 2100 South Frontage Road to northbound Bangerter Highway. Together, the new intersection and lanes will reduce delay through the intersection and along the intersecting corridors in the area.

Reducing delay

DDIs reduce delay by eliminating left turn signal phases. In typical diamond intersections, through-traffic waits for left turning traffic accessing on and off-ramps. Without a left-turn phase, through traffic can proceed without waiting for left turning vehicles.

A DDI also eliminates the need for signals at the on and off-ramps. Vehicles using the ramps have free right and left turns and simply wait for a gap in traffic.

Since traffic patterns vary depending on location, traffic analysis must always be done to make sure a DDI is the best choice.  Studies show that the DDI is a good fit for this location.

A cost effective choice

In addition to supporting better mobility and safety, the DDI is also a good cost saving project at this location. Because the existing bridge has adequate space, UDOT is rehabilitating the bridge deck and adding striping and signals for the conversion.

The DDI project is part of UDOT’s Bangerter Highway 2.0 , an expansive upgrade that includes improvements from the Salt Lake City Airport to 13400 South. The effort will reduce travel delay on Bangerter Highway by incorporating the latest innovations in transportation mobility.

Ultimately, the project will achieve all four of UDOT’s  strategic goals known as the “Final Four”: Take Care of What We Have, Make the System Work Better, Improve Safety and Increase Capacity.



Salt Lake City recently participated in a national effort to document the use of bicycle facilities on city streets.

"From the most casual recreational rider to the daily commuter there is a large population that rides," says Andrew Coffey, who coordinated a volunteer effort to count cyclists in Salt Lake City.

Salt Lake City has collected some data that will be available for engineers planning improvements to city streets and intersections. The Institute of Transportation Engineers  Pedestrian and Bicycle Council and Alta Planning co-sponsor the yearly  National Bike/Ped Documentation Project to provide local and national data showing how transportation facilities are used by cyclists.

According to the project website, “without accurate and consistent demand and usage figures, it is difficult to measure the positive benefits of investments in these modes…This nationwide effort provides consistent model of data collection and ongoing data for use by planners, governments, and bicycle and pedestrian professionals.”

Evelyn Tuddenham, UDOT’s Bicycle/Pedestrian coordinator says UDOT will conduct similar counts in the future. “Until you do the research, you really don’t know” if, when or how facilities are being used.

Andrew Coffey, Political Science Major at the University of Utah, coordinated the effort for Salt Lake City. He usually spends time studying international conflict and domestic politics. His internship with the Hinckley Institute of Politics offered something completely different – a chance to count cyclists.

Andrew Coffey U of U intern, counting cyclists on North Temple.

Coffey coordinated a bike count, modeled after accepted ITE methods for documenting vehicle usage, starting on August 23. “I was immediately handed the bicycle count project that day,” says Coffey. Coffey worked with Becka Roolf, Bicycle and Pedestrian Coordinator for the Salt Lake City Transportation Division.

The all volunteer effort took place during four days in August on selected intersections. Coffey solicited from and got great support from the cycling community. Results of the count will be released soon at an event held to thank volunteers for helping.

Coffey enjoyed his project. “Cycling can truly be an alternative method of commuting within the Salt Lake Valley, he says. “Even if you don’t ride your bike as your primary method of transportation, it is good to see that Salt Lake City strives to provide great facilities for bicycle riding.”

As he watched traffic and cyclists, he was troubled by the lack of helmet use among cyclists. He also noticed that like motorists, cyclists don’t always know the rules of the road. One thing that surprised him – there are a lot of, and many kinds of cyclists. “From the most casual recreational rider to the daily commuter there is a large population that rides.”


A Shift to Solar Powered Supplies and Greener Road Construction

Guest Post: Provided by Andrew Johnson, former employee of the UDOT Traffic Operation Center. (Images and information provided by Trans-Supply).

Environmental and economic sustainability is an issue that will continue to come up as new roads are constructed and repaired.

Solar powered equipment is becomming more common

Road construction is no small endeavor, and a new two-lane asphalt road with an aggregate base can require around 25,000 tons of crushed stone and costing millions of dollars per mile. It isn’t cheap, and it’s not easy, but even some simple changes can make a big difference.

Some of the recent “green” alternatives, from hot in-place recycling and adding old rubber tires as road filler to making the switch to solar powered barricade lights, are changing the way we look at road construction and maintenance. Some things, like switching out the lights, may seem like a small change, but there is a real opportunity there to save money and improve productivity.

Brandon Anderson, the owner of Trans-Supply.com, recently mentioned this increased interest in solar powered supplies and the trend away from battery-powered caution lights. “I have noticed a change in sales from battery powered barricade lights to their solar powered counterparts,” he said. “I believe this is due to solar technology becoming more affordable and making it a viable, economic alternative to traditional battery models. The sales for our barricade lights are almost exclusively solar, and that’s a win-win situation because it’s both cheaper and more environmentally friendly.”

Simply Solar

Solar-powered LED caution and barricade lights are becoming more common in road construction areas because they can – very reliably – draw attention in low visibility areas and warn drivers of dangerous conditions or obstructions without incurring the same costs. LED lights are durable, can last years longer than traditional lighting, and offer better distinction at long distances. They require less power to illuminate, reduce the costs of continually replacing batteries, have no filament that can burn out, and provide superior visibility even in poor conditions.

These solar devices are created by first determining how much energy the device will need to achieve autonomy (i.e. how much energy it will need to store to run without the aid of the sun), and then make sure it has a large enough battery to hold the necessary charge. Most regular batteries will need to be replaced once every three months (give or take). These batteries, on the other hand, require little to no maintenance and can power the efficient LED lights for years.

Solar powered road lights have been around for some time, and the same technology is being implemented more and more on everything from street signs and traffic lights to barricades and road studs. A good arsenal of traffic control devices will be an extremely effective tool that will increase safety and allow for better work production.

When lights rely on solar power instead of a tradition battery any barricades which have sat in storage for weeks, or even months, can be put into immediate use without having to check each device to make sure the battery hasn’t fully discharged. The same applies to renting these barricades or signs to others. It won’t matter how much they are or aren’t used, they can simply be moved to their new location where they will continue to provide reliable service.

In the past, the costs around solar technology have, unfortunately been economically prohibitive, but those costs are being driven down every day by new manufacturing techniques and other developments with the technology. It may seem like a small thing to switch from battery powered lights to solar powered, but even the little things will quickly add up when it comes to saving money and improving efficiency. And when road construction is already such a large and expensive endeavor, it’s important to take advantage of every opportunity.

Reuse and Recycle

NAPA (National Asphalt Payment Association) estimates that 18 billion tons of asphalt is already in place. The good news is that, with all new technology we have for recycling and repaving on location, we already have a great resource for our future roads. By reusing what we already have, there is a great opportunity to save money while building quality roads.

Asphalt is America’s most recycled product. More than 100 million tons of asphalt pavements are reclaimed every year, and the vast majority of it (more than 95%) is recycled or reused. By combining the reclaimed asphalt with materials from other industries – like used tires or roofing shingles – the entire road can be resurfaced without the same costs and effort behind using virgin materials.

The question of economic and environmental sustainability won’t just go away. If we overuse our resources, there will come a time when we will not be able to maintain our current levels of construction. At the same time, if we cannot sustain an economically viable business model, we will end up with the same results. These new green alternatives have become extremely effective, reliable, and efficient, and with careful management, we can maintain quality roads and minimize the impact on the environment.






A recently completed freeway project in Washington County has provided important travel and safety improvements for road users who drive the mountainous region.

Between the Black Ridge Mountains north of St. George to the Iron County line, I-15 is characterized by steep climbs and wildlife crossing the freeway. The important commerce and recreation corridor carries UDOT Region Four’s highest traffic volume with 25,000 vehicles a day, including 5,000 trucks, moving in both directions. A project to build new climbing lanes and install extensive wildlife fencing reached substantial completion in late September and UDOT has already received some positive feedback on the improvements.

Utah State Troopers noticed better traffic mobility right away, and called to tell UDOT Station Supervisor Todd Abbott. “They think it’s far out.” Abbot has been in touch with Point of Entry workers too, who indicate that local and interstate freight carriers are happy about the new lane too.

Black Ridge -- with only two lanes, road users experienced delay during peak travel times.

All road users are inconvenienced by travel delay, which also has an associated cost. But the extra lane offers the most noticeable benefit to passenger vehicles – “what an improvement, to get up the mountain from St. George to Cedar and not get behind two semis,” says UDOT Project Manager Scott Goodwin. Before the project, traffic on the two lane-north bound side of I-15 could be sluggish during peak travel times.

Goodwin managed Region Four’s first Design Build with the Black Ridge project. Anticipating the new lane would be built on the outside of the freeway, Goodwin was surprised when the contractor proposed building the entire project in the median. “It required more help from geo-tech – Jim Higbee was very involved,” says Goodwin. “It turned out to be a really nice project,” with the added lane and 12 feet of maintenance area between the mountain and new barrier. ATMS conduit and cable was installed through the project and south of the project, in an area improved two years ago.

UDOT works with the Utah Division of Wildlife Resources to identify appropriate improvements that work for wildlife.  Bruce Bonebreak, UDWR Habitat Manager appreciates the efforts to make interchanges, box culverts and other freeway areas more wildlife friendly. “This deer herd has suffered a lot in recent years from highway mortality when they try to access the winter ranges,” says Bonebreak. UDOT “has done a very commendable job” of working with UDWR.

Wildlife fencing was installed along both sides of I-15 from the lower part of the Black Ridge to the overpass west of Kanarraville, providing protection for over 12 miles of freeway. “This area has long been plagued with high numbers of collisions between vehicles and deer, particularly during the late fall to early spring period,” according to Randall Taylor, UDOT Resident Engineer. “At freeway speeds collisions are serious. Car parts and the carnage of deer carcasses along I-15 resulted in pleas for help from local residents.”

I-15 adjoins 2500 acres of land owned by the Indian Peaks and Cedar Bands of the Paiute Indian Tribe of Utah, and the Tribe also has an interest in reducing wildlife-vehicle collisions. Tribal efforts include improving plant life on the east side of the freeway to provide food for animals so hopefully, fewer try to cross. “If we can improve habitat on the east side of the freeway, it will not only save deer and elk, but also people,” says Gaylord Robb with the tribal office. Robb has secured a grant from the U.S. Fish and Wildlife Service that will provide additional fencing with an upcoming UDOT project.

The Black Ridge to Iron County project is the most in an ongoing effort to improve safety and traffic mobility on I-15 from the Arizona State line through Utah. Project Manager Scott Goodwin talks about taking on UDOT Region Four’s first Design Build with this project in a previous post.


Materials engineer John Butterfield discusses concrete pavement with workers on the I-15 Corridor Expansion Project.

UDOT Engineers from many different areas of expertise work together at improve our transportation system.

Most engineers at UDOT are civil engineers. Civil engineering is a designation for professionals who design, build and maintain structures in the natural and built environment.

Some common activities of all engineers include preparing reports and cost estimates, writing specifications and collaborating with engineers of other specialties. Within civil engineering, there are many specialties. At UDOT, most engineers fall into these categories:

Construction: Build and maintain roads and associated structures. Manage a team of engineers and technicians to inspect the work of contractors, monitor progress and pay bills.

Design: Design new roads or improvements to existing roads. Road features can include barrier types, curb, gutter, sidewalk, striping and sign layout, Coordinate with other design engineers for bridges, drainage systems, etc.

Geo-technical: Analyze and evaluate the natural environment to provide systems that support built structures associated with the transportation system. Design footings and foundations for bridges, design landslide mitigation, determine processes to prevent or mitigate settlement of roadway embankment or structures such as mechanically stabilized walls, retaining walls, bridges etc.

Hydraulics: Determine bridge length and geometry over rivers by analyzing the stream flows and taking into account potential events like storms; design roadway drainage systems.

Materials: Analyze and test materials, mainly concrete and asphalt used to build road surfaces, and determine the strength properties and insure to insure durability.

Project: Manage project budget, schedule and scope from design through construction.

Structural: Design, modify and maintain roadway structures such as bridges, box culverts and retaining walls. Perform inspections of bridges and propose projects to improve stability or to fix structures to meet new demands, such as increased traffic.

Traffic:  Analyze traffic movement using computer simulations to see how freeways and intersections function under different conditions such as changing traffic volume, road width or signal time. Determine the timing of new signals and make changes and improvements to existing signal timing to improve safety or mobility.


Recent cold weather is a reminder that snow is on the way. One way UDOT prepares for winter weather is by stocking road salt at maintenance facilities around the state.

Redmond, Incorporated operates this salt mine in Central Utah. The salt is a remnant of an ancient sea. A variety of products, including road salt are produced from the mined salt.

Road salt deliveries have occurred in some of the high mountain areas and soon all UDOT Maintenance Station storage facilities, in areas where snow is expected, will have plenty of salt on hand.  UDOT uses 215,000 tons of salt per year —  two-thirds solar salt, one-third rock salt.

“As essential to life as water – ubiquitous – so precious anciently that Roman Legionaries were paid their wages with sal, which is Latin for Salt,” says UDOT Maintenance Methods Engineer Lynn Burnham. “Hence the English word salary.” Bernhard earns his salary planning maintenance methods that keep UDOT roads safe and clear.

Wet salt will re-crystallize with a hard crust that’s difficult to break up, so most salt is stored in covered salt sheds that keep salt dry during stormy weather. Salt is stored at 80 maintenance facilities and 26 other storage areas around the state. There is no central stockpile.

Salt is purchased on contracts set up at UDOT headquarters, and station supervisors order the amounts and type needed for the roads in their area. Most stations place their orders in September and have their salt sheds full by mid October.

UDOT buys reddish-brown rock salt from an underground mine in Central Utah and white evaporated or solar salt from the Great Salt Lake. Both types work well, but salt types have different properties so station supervisors order what works best in each specific climate.

“Utah has an advantage over other snow-belt states,” says Bernhard. “Our salt sources are literally in our own backyard, so we do not have to order a full year’s supply at one time.” Other states anticipate the amount of salt needed and order a year’s worth at one time. If accurate estimates are not made, salt may run out, and leave workers in the lurch.

A truck is loaded with salt from the Great Salt Lake


“We could place an order one day and expecting delivery by the next afternoon,” says Bernhard, who adds that UDOT supervisors keep very close watch on inventory so one-day delivery is not needed. “Our goal is to end the snow season with no salt left in our stockpiles.”



FHWA has given UDOT and partner agencies an award for successful wildlife mitigation efforts on U.S. Highway 6.

First to be photographed at Beaver Creek Bridge

Beaver Creek Bridge on US-6

A diverse team of experts from federal and state government joined forces in 2005 to find better ways to help wildlife get across US Highway 6 between Spanish Fork and Price, Utah. Members from the Wildlife Coordinating Committee, drawing from FHWA, UDOT, U.S. Fish and Wildlife Service, Utah Division of Wildlife Resources, the Bureau of Land Management, Uinta National Forest Service, and Utah State University, collaborate to identify high wildlife-vehicle collision spots and make recommendations for improvements.

“Their efforts are showing measurable success,” says Brandon Weston, UDOT Environmental Manager and chairman of the committee. FHWA has recognized that success with a Exemplary Ecosystem Initiative Award.

The committee has been successful by studying wildlife habitats, building cross-agency partnerships and using innovative solutions backed by the best science available, according to Rebecka Stromness, past UDOT Environmental Manager.  Stromness wrote the nomination for the award, which points out that many past activities, including  construction of the original road and railroad, logging, fur trapping, livestock grazing, agriculture, and urban development, have served to eliminate or degrade wildlife habitat. “With the implementation of mitigation for each specific project, vehicle-wildlife collisions are being reduced and wildlife movement across the highway is gradually being restored.”

Professor Patricia Cramer, a wildlife research assistant professor with Utah State University, is tracking the success of crossings by placing cameras to record images of wildlife. Cramer joined the committee years before research started. Knowing UDOT was planning an ambitious and challenging effort to improve safety on US-6, she saw the potential for the highway to be the “crown jewel of wildlife crossings in Utah.” Her research started with a UTRAC grant and continues with funding from Utah Division of Wildlife Resources.

Doug Sakaguchi, Habitat Biologist with the Utah Division of Wildlife Resources, has served on the committee since 2005. The success of the committee in collaborating to reduce the number of wildlife killed is “exciting to me,” says Sakaguchi. His graph (below) shows a reduction in the number of carcasses before and after two bridges were replaced with new bridges that accommodate wildlife movement.

Before and after (click to enlarge). A new bridge planned at Mile Post 203 will allow wildlife to cross.

Weston, Cramer and Sakaguchi point to a railroad bridge replacement project at Mile Post 200 as an example of a successful outcome. The old structure, a three-span steel girder bridge, needed to be replaced. The new bridge that accommodates the rail lines limits the ability of wildlife to cross. Through the committee’s efforts, a wildlife crossing was added to the project just west of the new bridge. The new crossing allows over 800 Mule Deer each year to cross under US-6.

The committee provides a model that shows how agencies can work together to improve highway safety and reduce animal-vehicle collisions, explains Weston. The committee’s job with US 6 is nearly complete, but members will continue to meet to discuss research and wildlife mitigation efforts in other parts of the state.

“We are not starting from scratch anymore,” says committee member Ashley Green, UDWR Wildlife Coordinator for Statewide Projects. He is confident that other areas of the state can benefit from cross-agency cooperation even though wildlife crossing areas pose problems that are “difficult, complex and not easy to fix,” he explains. “We have seen some really awesome success.”

In addition to improving wildlife crossings, UDOT has added new bridges, general purpose and passing lanes, concrete barrier, guardrail, centerline and shoulder rumble stripes, warning signs and improved the road alignment on US 6.

Read more:


The first portion of the Mountain View Corridor opened first to runners, then motorists.

Created with Admarket’s flickrSLiDR.

The first three-mile section of Mountain View Corridor (MVC) in Utah County opened to motorists at 2100 North in Lehi. Hundreds turned out for a charity 5K, Fun Run and community BBQ to mark the occasion. All proceeds raised at the event will support four local charities including North Point Elementary School, Hess Cancer Foundation, Boys and girls Club of Utah County and Anything for a Friend.


New pavement markings in Echo and East Canyons will improve visibility and safety at night and during storms.

This slide show provides a few images of work done this week in Echo and East Canyons. Click on the large images to see captions. Place your cursor in the bottom portion of the show to select another image.

Created with Admarket’s flickrSLiDR.

A past UDOT Blog post gives more information about how UDOT is testing beads and grooving pavement.


A Utah product could be the answer to more durable asphalt roads.

SR-121 near MP 29

Three thirty year old roads in Utah are aging remarkably well. While other asphalt roads in the area have been rebuilt, Randlett Road, the Bonanza Highway and SR-121, between Maeser to Lapoint near Vernal, Utah, show minimal wear and very few ruts and cracks compared to other roads that carry similar loads. What’s the difference? Pavement made from native asphalt excavated in Utah.

“It’s pretty stout,” says UDOT Engineer for Asphalt Materials Kevin VanFrank who has tested oil sands pavement with a Hamburg asphalt mix performance tester. After over 12,000 passes with the machine’s weighted wheel, the old pavement showed similar wear as compared to newer typical asphalt mix designs used on similar roads.

Old oil sands mix designs varied in the past. SR-121, Maeser to LaPoint was paved in road mix method using kerosene as a cutter to mobilize the oil sands. Randlett Highway and the Bonanza Highway were paved using a hot mix. To make use of oil sands today requires a standardized design that considers repeatability and durability.

Standardized design

Core sample of asphalt pavement made from oil sands

Oil sands, mined in the Uintah basin, are a source of natural asphalt that have been used in pavement for 80 years, explains Kimball Young, who is overseeing a project to put the product to work for the Uintah Transportation Special Service District with support from USTAR. Young’s project team has developed a non-proprietary design and placed oil sand pavement in test areas in Uintah County. Plant Mixed Oil Sands Asphalt uses un-processed oil sands along with the usual pavement components – crushed aggregate and hydrated lime.

The mix development process started with testing the old pavement. VanFrank worked with University of Utah researcher Pedro Romero on initial testing. Young worked with Tim Biel of CME Transportation group to continue the testing and development of a mix design that produces a stable mix and can be reproduced. Romero has maintained his involvement throughout the process.

All testing showed that pavement made from oil sands can produce high quality, durable pavement for light to medium traffic loads. The durability of oil sand pavement may be due to slower oxidation rates in natural asphalt as compared to asphalt from refined petroleum, explains Biel.

The mix design developed by Young’s team is composed of 35 to 40 percent oil sand containing  a minimum of 12 percent asphalt and 60 to 65 percent course aggregate. Young’s team is testing warm mix designs with and without hydrated lime.