New I-15 Sign in Cedar City, Utah

Interstate signs are updated to improve safety and provide better readability and directional help for road users.

New signs have been placed on Interstate 15 near Cedar City. The signs meet new Federal standards and the messages on the signs have better relevance to the local area.

As interstate signs age and Federal standards change, UDOT identifies interstate segments that could be improved by a sign facelift. Sometimes single signs need to be replaced due to fading or other damage, but replacing a sequential group, as exemplified by the Cedar City project, gives UDOT the chance to update a series of signs that work together to provide clarity and consistency for road users.

Evaluation of old signs is based many factors. Current Federal standards are outlined in the Manual on Uniform Traffic Control Devices (MUTCD). Here are three broad areas engineers consider when prioritizing sign replacement projects:

Retroreflectivity: Light that bounces back to a light source instead of being generally diffused is retroreflective. “It’s right back at you,” says Wes Starkenburg, Sign Engineer at UDOT. Signs use sheeting and tape with prismatic reflectors that send headlight beams back to drivers.

Federal requirements determine the level of reflectivity of all signs on roads with public access. The level of retroreflectivity is evaluated by a trained sign inspector who visually inspects sings. Wear from weather and sun can decrease the level of retroreflectivity making signs harder to read. A trained eye taking a look at signs at night is a good start. Using a retroreflectometer allows an objective evaluation.

According to FHWA, approximately three times as many crashes occur at night, making retroreflectivity of signs an important safety feature.

Readability: Lettering used on interstate signs, sometimes informally called “Highway Gothic” is simple and easy to read. Spaces between letters, the shape and size of lettering are consistent from sign to sign which helps avoid confusion.  The number of words should be limited so signs can be read quickly.

Messaging: As cities grow and small towns become more urban, messages on signs can become outdated. To make sure a series of signs helpful to road users, UDOT works with local elected or transportation officials to develop new messages to provides good directional help.


A project to install new welcome signs around the state also gave UDOT a chance to use a new sign base.

The new Welcome to Utah signs gave UDOT a chance to use a new sign base.

Welcome to Utah signs placed last year feature Utah attractions and a breakaway type base that’s new to UDOT. A similar design has been used successfully in Idaho and other states for many years. The signs were placed in or near clear zones on interstates and at Utah Welcome Centers.

Clear zones are designed to allow errant vehicles a place to safely stop or re-gain control.    Signs that are installed in the clear zone are required by the Manual on Uniform Traffic Control Devices to be protected by a crash cushion or have a breakaway design – that is, in a crash, the sign post should break away from the base and go over or under the vehicle.

It’s long been known that breakaway signs are safer for drivers than rigid signs.  In 1963, the Texas Highway Department, the Texas Transportation Institute and the U.S. Bureau of Public Roads cooperated when “Substantial miles of the Interstate System was under construction or scheduled for construction” and the need for safer sign supports was imperative. New sign bases were designed, tested and put into use. (Highway Research Record #174, Guardrails, Barriers and Sign Supports)

This interactive timeline on the TTI website shows that crash testing on breakaway sign bases was conducted at their facility in 1964, and the first known life saved as a result of a breakaway sign base was documented in 1965.

The new sign base has been tested according to Federal requirements, but UDOT Traffic and Safety wondered how well the sign base would hold over time. Since the signs are placed throughout the state and subject to all kinds of weather, the welcome sign project provided a good chance to find out how the base performs in high winds or heavy snow – so far, the sign bases are working well.

The posts on new base are secured to footings using couplings that break away in a crash leaving a very short stub. Joints on the posts also cause the sign to fold on impact. The design limits property damage to the road user and UDOT. After the base is damaged, repair is simple and inexpensive; posts can be re-bolted using conventional tools. “It is a matter of changing the hinge plates on the posts and couplings on the ground,” according to Customer Services Representative for the vendor. Because of the design, “usually the posts do not need to be replaced.”

Dave Skinner, Road Operations Coordinator in Region Three near the Wyoming State Line sees all kinds of extreme weather.  “You name it… cold, snow, rain, and very high wind,” he says. High winds regularly damage signs in his area. “Last year, the wind got a whole bunch of them,” he reports. But the new sign base has held up under daily windy conditions that range between 20 and 50 mph.

UDOT Traffic and Safety is looking forward to working with the UDOT Regions to identify other appropriate places to use the new sign bases.


UDOT and local charities will hold a fun run on a new portion of the Mountain View Corridor in Utah County.

Before the tire rubber hits the road, runners are invited to put shoes to pavement to celebrate the opening of the first section of Mountain View Corridor. Several local charities are working with UDOT to hold a 5K & Fun Run on Saturday, September 24, 2011. All proceeds raised at the event will benefit North Point Elementary School, Hess Cancer Foundation, Boys & Girls Club of Utah County and Anything For a Friend.

Visit the Mountain View Corridor website for more details or to register for the race.

This video shows an overview of summer construction progress:


Heading to the big game on Saturday, September 17? I-15 CORE construction will cause traffic delay on I-15 that may make the trip up to twice as long. Leaving early is the best strategy for making the game in time for kickoff.

UDOT strongly encourages southbound drivers to use the Orem Center Street, 800 North and University Avenue exits. University Parkway is open but heavily congested. Northbound drivers are advised to use the University Avenue exit or State Street to 900 East.

One change drivers will need to plan for is in Provo, where the southbound off-ramp at Center Street is closed through November.

Here are some ways UDOT is helping fans avoid some inconvenience:

  • On game day, UDOT will be working with Orem and Provo to monitor traffic cameras and coordinate signals to help keep vehicles moving. UDOT will also send regular traffic updates to KSL Radio to keep drivers informed of the best routes for getting to and from the stadium.
  • Football fans can subscribe to the I-15 CORE text service for traffic updates. Text “i15” to 53535 for up-to-date construction information.
  • UDOT encourages drivers to stay informed about the latest I-15 CORE construction by signing up for regular email updates, or becoming a fan of I-15 CORE on Facebook or Twitter.



Researchers have some new insight on what happens to safety barrier systems on mechanically stabilized earth walls during a crash.

MSE walls are familiar structural elements on Utah's highways. How barriers on MSE walls perform in a crash is the subject of a recent study.

According to the Texas Transportation Institute, approximately 10 million square feet of MSE wall is constructed every year in the United States. UDOT has a database of over 700 walls in use to support backfill around bridges and freeway ramps or for retaining walls along freeway corridors. MSE walls are relatively new features in the transportation world; UDOT’s oldest walls were built about 30 years ago. Useful life of the walls is expected to be 75 years.

Test MSE wall under construction

Because of the newness of MSE walls, research is needed in many aspects of design and construction. UDOT Geotechnical Engineer Grant Gummow recently participated in a TRB sponsored National Cooperative Highway Research Program study that focuses on concrete roadside barrier systems on MSE walls – that is, how the barrier system performs as a safety device and how the system can be designed to protect the MSE wall from damage.

MSE walls are built in lifts (layers) of fill with steel or geosynthetic reinforcement. Concrete panels or blocks are used as facing to retain the reinforced backfill. Facing materials are anchored using welded galvanized steel wire mesh, steel straps, or geosynthetic grids embedded in the retained backfill.

MSE walls barrier system design was borrowed from bridge design principles. Barriers are usually attached to a coping, which in turn is attached to a moment slab (footing) covered with overburden soil. The components of the system work together to avert a vehicle from tumbling over a wall, redirect the vehicle in a path that is parallel to traffic and to distribute the load over a wide area to limit potential damage to the internal structure of the MSE wall.

UDOT’s barrier systems, and across the country, seem to be working well. Without objective studies, “it’s difficult to know how conservative the design is,” says Gummow. “We don’t want to over-design.” Safety is paramount, but a design that’s too conservative wastes funding and resources.

Crash testing

Researchers tested a variety of MSE wall reinforcements and two barrier types, Jersey and a vertical barrier, all representing current building and design practice. The MSE walls were built for the study and outfitted with strain gauges to measure the degree of deformation that occurs when pressure is applied.

Crash testing took place in stages. First, a jack was used to push against the barrier. Next testers used a bogie vehicle – a steel frame with weights to approximate a car – to crash into the barrier. The third type of testing was done with an actual car. The unmanned crash car was pulled by another vehicle using a cable and pulley system that released the crash car at the desired angle at a speed of approximately 63 mph.

Computer modeling

A Computer model was used to conduct a Finite Element Analysis. The model used a very detailed computer image of a standard sized pickup truck that showed, right down to minute bumper movements, what happens to a truck in an actual crash. The barrier in the model was set up to show how the components of the system, including steel reinforcement, are impacted in a crash.  By using computer modeling, the researchers were able to vary angles and speeds and then measure and assess damage to the truck, barrier system and MSE wall.

The results of the study provide the basis for new Load-and-Resistance Factor Design specifications for barrier systems on MSE walls.


Transportation officials from four states are looking for better ways to let road users know about travel delay on I-80.

East bound I-80 in Parley's Canyon

Stretching from I-101 in San Francisco to the Jersey Turnpike, I-80 is the longest interstate freeway in the United States and is a critical route for moving people and goods. California, Nevada, Utah, Wyoming and Nebraska share a part of the route. Each state has areas that could be considered “mostly weather related” trouble spots, explains coalition member Rich Clarke, UDOT Director of Maintenance.

Donner Summit in the Sierra Nevada Mountain Range is an area where snow removal can delay travel for hours and sometimes days. In Utah, I-80 crosses the Great Salt Lake Desert, a long, straight segment where wind can also make travel treacherous. Parley’s Canyon in Utah closes in winter due to high snowfall and dangerous travel conditions. In Wyoming, I-80 is subject to winter and summer closures due to wind through the Wind River region. Nebraska experiences west-bound back-up when Wyoming closes, so coalition partners depend on Nebraska officials to let road users coming from the east know what’s ahead.

Informing truckers about delay

Keeping traffic moving through or around the trouble spots is good for road users and the local and national economy because travel delay has a real and measurable economic cost . The I-80 Coalition is an effort to keep traffic flowing and let road users, mostly truckers, know about traffic delay – and the earlier that notification takes place, the better.

“If we can tell a trucker in Sacramento that he’s going to run into problems when he gets to Parley’s, then he has a lot of room to make decisions,” says Clarke. “In the Salt Flats, his options have decreased but it is still better than waiting until he becomes stuck in Parley’s where he is not only out of options but has now become part of the problem. It is our hope that if he gets the word early he can take another rout or finds a place to lie over until the roads clear.”

UDOT Meteorologists

Two other UDOT people are also participating in the coalition. Leigh Jones, Weather Information Systems Program Manager and Daniel Kuhn, UDOT Railroad and Freight Planner. UDOT’s weather gathering system is cutting edge, and meteorologists provide information to surrounding states. Kuhn is an expert on truck traffic and the trucking industry.

Whatever it takes

The Nevada Department of Transportation is the lead agency for the coalition. Members meet biannually and communicate often between meetings. While the group also deals with safety issues, like chain-up laws, the I-80 Coalition is largely a communication effort, explains Clarke, with the number one priority being serving the public by keeping traffic flowing. Last year, the group used snow storms as a communication exercise. Members teleconferenced and “went through the process of talking to each other about what was happening in other states.” The exercise helped to build communication links between states.

When it comes to communication platforms, the coalition is looking at all available options, including Variable Message Signs, Highway Advisory Radio and using weigh stations. “Websites, social media, tweets, whatever is available out there,” says Clarke. Truckers typically have laptops in their cabs. Informing motorists, especially truckers, about delay will keep traffic flowing and goods and people moving along the critical route.

How important is I-80 to interstate commerce? A post by Daniel Kuhn provides an interesting perspective on the importance of I-80 to the United States and Canada.


Today, a guest post by Daniel Kuhn, UDOT Railroad and Freight Planner.

Interstate Highway 80 is one of the most strategic and important of all freight highways in North America.

I-80 is part of an interstate network

While most motorists know I-80 as the main route between New York City metro area and San Francisco via the Chicago area, Omaha, and Salt Lake City, to the trucking industry I-80 is a network of routes. All along its transcontinental route, I-80 has a variety of connecting roads that feed long-distance freight to and from the main highway. Here in Utah we are at the junction of two of the I-80 Network’s most important and busiest freight feeders, I-15 from southern California and I-84 from the Pacific Northwest. Northern Utah is literally the hub of the I-80 Network for freight.

Thousands of trucks use I-80 and its feeder network every day, carrying a myriad of products to and from destinations all over North America. Canadian trucks are a daily sight all along I-80 in the west, with many connecting to I-15 in Salt Lake City. Of all the freight carried on the I-80 Network, the movement of perishable freight, such as fresh fruits and vegetables, in refrigerated (“Reefer”) trucks is by far the most time-sensitive.

During harvest season here in the west, which usually runs from June through October, reefer trucks account for around 30 to 40% of total truck traffic along the I-80 Network, approaching 50% east of Utah on I-80 itself. A combination of factors, including regional geography, the undertaking of large water projects and agricultural developments across the west in the early 20th century, and advances in mobile climate control systems for semi trailers has led to Utah being the crossroads of perishable freight movement in the western United States. As a result of our crossroads status, a number of refrigerated trucking companies, including the nation’s largest, C.R. England, Inc., are headquartered in the Salt Lake Valley at the hub of the I-80 Network.

C.R. England Global Transportation photo used by permission

The majority of perishable freight passing through Utah is grown in California’s fertile Central Valley, which produces almost 25% of all the fruits and vegetables consumed in the United States. These time-sensitive products travel to Utah via I-15 or I-80, using I-80 and to a lesser extent I-70 beyond the Beehive State. As a result, Utah’s Primary Freight Routes, including several that are a part of the I-80 Network, are a strategic part of America’s, and Canada’s food transportation system.

Trucking moves what America consumes, and UDOT’s highway system plays a vital role in making the American lifestyle possible for many in the USA. The I-80 Network serves as the vital backbone of routes which move freight to, from and through Utah en route all across America and to much of Canada as well.

For more:

Wyoming Freight Study

Geography and Freight Fact Sheet

Refrigerated Freight Fact Sheet



Municipal primary elections are today — be sure to vote.  AND you can vote twice; UDOT’s 3500 South project is in the running for a people’s choice award.

The 3500 South Project was widened to include three travel lanes in each direction and a center-running dedicated lane for UTA’s Bus Rapid Transit line. The project was completed 7 months ahead of schedule and $6 million under budget. Early completion also saved the public $2.3 million in road user and safety costs.

Click here to vote.

After construction: Center running lanes for UTA's Bus Rapid Transit extend from 2700 West to Bangerter Highway.


A Smoother Road Could Lead to Energy Savings and Increased Safety

A road near Arches National Park.

This guest post is provided by Andrew Johnson, former employee of the UDOT Traffic Operations Center.  

The rising gas prices have had an effect on all of us, one way or another, and without any relief in sight, many of us are looking for ways to save money and improve fuel efficiency. When we think about ways to improve mileage and save money, the factors that usually come to mind involve aerodynamics, engine efficiency, and tire pressure, but recent studies suggest that there is at least one external element that could impact both safety and energy savings.

Dr. Richard Willis, an assistant research professor at Auburn University, reported that some simple improvements to the smoothness of road pavement could save a lot of money. He suggests that, in total, we could save 2.4 billion gallons of gasoline and 900 million gallons of diesel every year, which would lead to an estimated $12.5 billion.

The problem is from something called rolling resistance, which can be defined as the energy that is lost between the tire and road. The imperfections in the pavement, as well as the stiffness of the tires, directly affects how energy is lost and how much is required to keep the vehicle in motion. Of course, it shouldn’t come as a real surprise that the less time we spend bouncing around on roads and highways, the more efficiently our vehicles will run.

Understanding the Numbers

The numbers for the above study were broken down like this: In 2010 a study by Schmidt and Ullidtz showed that slight improvements in road smoothness could yield reductions in fuel consumption by 1.8 to 2.7%. Some other studies have actually suggested that this number could be much higher – as much as 4.5%. The Bureau of Transportation Statistics, on the other hand, says that vehicles consumed 168 billion gallons of gasoline and diesel, which means that at an average price (according to AAA) of $3.66 per gallon ($3.93 for diesel) and a conservative estimate of 2% fuel reduction, we arrive at the $12.5 billion figure.

Driver Safety

The National Highway Traffic Safety Administration says that one third of all highway fatalities can be attributed to poor road conditions. Perhaps a little surprising is that most of these fatalities happen on two-lane, while the highways are comparatively safe. The combination of better road quality and better conditions (better visibility, wider lanes, etc.), actually seems to be more conducive to safe driving.

Utah’s Road Conditions

So how well has Utah done with providing smooth roads? According to the Federal Highway Administration – pretty good. The FHA released some statistics in 2008 that put Utah near the top for maintaining good roads. Of Utah’s roads, only 6.4% were considered to be in poor or mediocre condition, which is pretty good compared to states like New Jersey or Hawaii (48.6% and 44.4% of their roads, respectively, were considered to be in poor or mediocre shape).

More and more studies are showing us exactly how important it is to maintain our roads and look for ways to improve driving conditions. While there is a lot of internal factors that affect driver safety and energy usage (from engine efficiency to simply being a conscientious driver), a smoother road can have more impact than many of us think.

Image and information provided by Online Driving University and the National Highway Traffic Safety Administration.


American Road and Transportation Builders Association, FAQs

National Asphalt Pavement Association, Press Release



Summer is spent getting ready for winter at UDOT’s Heavy Equipment Shop.

Rust holes in the side of a truck bed are gone. After a few coats of orange paint, this truck will be ready for winter.

John Walker, UDOT Equipment Shop Supervisor calls the employees who repair heavy equipment “talented craftsmen.” The before and after photos of the truck show the results of their careful work. This truck will be painted, and then be ready to be put back in service before the first winter storm.

Holes in the side of this truck were repaired.