Pollution is certainly a problem in the real world, and especially in our nation’s waterways. Everything from household cleaners to industrial waste can end up in our reservoirs and lakes.

The Texas Department of Transportation (TxDOT) and Texas Transportation Institute (TTI) fund TTI‘s Hydraulics, Sedimentation, and Erosion Control Laboratory (HSECL), a state-of-the-art facility focused on our nation’s water quality. Other states use the facility through the HSECL Pooled Fund Project, an effort supported nationally by the Federal Highway Administration (FHWA). This project maximizes the lab’s capabilities and gives the participating states priority in using the facility and receiving test results.

“The HSECL provides the transportation industry a uniform and timely testing and research program,” states Associate Research Scientist Beverly Storey, who also heads TTI‘s Environmental Management Program. “Products, materials, devices and methods used for storm water quality improvement, erosion and sediment control, and the design and management of sustainable roadsides all fall under research done at the facility, that is then shared with other state transportation agencies.”

Sediment runoff is the number one pollutant of our waterways, according to the Environmental Protection Agency (EPA). Contaminants, such as oil and gasoline, can attach to the sediment particles and be carried into water supplies by storm water runoff. During road construction, sediment retention is particularly difficult to manage, but TTI Assistant Research Scientist Jett McFalls says it is imperative that appropriate measures be taken to ensure regulatory compliance.

TTI‘s facility is recognized as one of the premiere facilities of its type in the world. Since 1990, the HSECL has regularly updated the Approved Products List (APL) for erosion control materials it created in 1990. Many states, and even some municipalities such as Austin, Texas, not only utilize the APL, but also require manufacturers to have their materials tested at the facility prior to approving its use.

“For the first time, runoff at construction sites will have to meet EPA restrictions called Effluent Limitation Guidelines,” says McFalls. “Although we don’t expect the new guidelines to come out for a few years, we’ll already know which products meet those restrictions due to the new Sediment Retention Device [SRD] testing program.” The SRD test flume is the first full-scale testing program and will soon lead to an APL being developed for such devices.

“The HSECL is a valuable tool for TxDOT and TTI in testing erosion control products,” explains Dennis Markwardt, director of vegetation management in TxDOT‘s Maintenance Division. “The lab has proven itself over time by producing reliable, meaningful data. Expanding into the sedimentation arena will continue to provide benefits for Texas and the rest of the nation.”

The Federal Highway Administration (FHWA) originally aimed its Manual on Uniform Traffic Control Devices (MUTCD) at ensuring that signs and markings were uniform in their design and placement. This promoted consistent recognition on the driver’s part, which reinforced learning and guided driving behavior. More recently, FHWA expanded the role of the MUTCD to include specific maintenance performance levels.

“Under its original mandate, the MUTCD mentioned maintaining signs and markings for ‘adequate visibility’ but didn’t really define what that was,” explains Paul Carlson, head of TTI‘s Operations and Design Division. “Over the past decade, TTI has been working with FHWA to help create those minimum maintenance performance standards for properly assessing the nighttime visibility of signs and markings.”

Helping Local Agencies Improve Sign Retroreflectivity

Since nighttime crashes occur at nearly three times the rate of daytime crashes, improving visibility at night has become a national priority. To increase their visibility during nighttime conditions, signs are covered by retroreflective sheeting materials. So, how well a sign reflects light — it’s retroreflectivity value — is especially important to traffic safety at night.

“Signs typically have a lifespan of 7 to 15 years. Over time, their retroreflectivity suffers death by natural causes, so to speak,” explains Carlson.

Their number one killer? Ultraviolet light.

As retroreflectivity degrades, the ability of signs and markings to help drivers navigate safely fails as well. So FHWA recently established a sequential set of deadlines by which all agencies must comply with new retroreflectivity standards for warning, regulatory and guide signs. But this could prove challenging for some since sign maintenance usually occurs at the local level — and not every community has a traffic engineer on staff.

Carlson and his team recently partnered with FHWA to determine what maintenance methods were most effective in assessing signs for replacement. Taking the needs of small cities, counties, townships, and Tribal and federal land management agencies into account, Carlson’s team created the Retroreflectivity Toolkit. It’s a step-by-step, how-to guide that empowers agencies to choose a method that best suits them and even helps them create a sample budget as they begin their maintenance planning. The toolkit, containing a guidebook and interactive CD-ROM, should be available this summer.

“The toolkit puts the procedures necessary for meeting the new maintenance standards in the hands of every small agency nationwide,” explains Matt Lupes, highway engineer with FHWA‘s Office of Safety. “Lives will be saved as a result.”

But Carlson and his team haven’t stopped there. They’re currently working on a project to improve the way agencies test how effective road markings are on rainy nights.

(Re)creating the Standard for Testing Wet-Weather Pavement Markings

In 2005, Carlson’s team completed a study for the Texas Department of Transportation (TxDOT) to evaluate the testing of wet-weather pavement markings. More specifically, they evaluated the testing method recommended under ASTM International’s E 2176-01 standard. What they found was disturbing.

“When a standard test method comes out, departments of transportation around the country begin adapting their specifications based on the test method results,” says Carlson. “What we discovered was that the E 2176-01 standard test method for taking retroreflectivity measurements on rainy nights wasn’t valid for the vast majority of pavement marking materials.”

As a result, anyone using that method to test their wet pavement markings at night is likely generating data that don’t accurately reflect true nighttime wet performance. Often markings rated as “bad” using the method are actually fine. If agencies base their decision on these data, they could end up replacing markings before their time, unnecessarily increasing overall maintenance costs.

“Currently, there is no reliable standard test method for conventional pavement markings,” Carlson notes. “It’s extremely important to get a standard in place because it’s not uncommon for reflective materials to work extremely well during dry periods but poorly during rainy conditions.”

On March 24, Carlson invited his fellow ASTM International Technical Committee members to Bryan/College Station to gather data using a new standard test method created by TTI. The method is specifically designed to provide accurate measures of pavement marking performance under continuous wetting conditions. The test results have been documented and were discussed during June’s ASTM International meeting. If all goes as planned, a standard could be in place by the end of the year.

“This is a great example of how the entire nation benefits from excellent research at the state level,” explains Carl Andersen, Roadway Team Leader in the FHWA Office of Safety Research and Development. “While Paul’s TxDOT project was aimed at improving nighttime driving safety for Texans, citizens all across the country — all around the world, in fact — will benefit from the findings.”

When he discusses his work and its global impact in improving safety, Carlson is somewhat philosophical.

“That’s why I do this job. Research is interesting in its own right, but making a difference in people’s lives based on that research — now, that’s what we’re here for.”

This story first appeared in the May 2009 issue of The Road Beacon.

A similar change has occurred following terrorist attacks of the last 15 years, where the preferred weapon of terrorists worldwide has become the car bomb.

“Anti-ram barriers are typically used around government buildings, infrastructure facilities, military installations or any other location where terrorist activity is a threat,” explains Dean Alberson, program manager and assistant director at the Texas Transportation Institute. “These barriers keep vehicles away from buildings to minimize damage should a car bomb explode.”

In 1985, the U.S. Department of State (DOS) created an anti-ram standard for protecting its embassies. The standard was designed to stop a medium-duty, single-unit truck and accounted for three levels of blast penetration.

Consular facilities are often squeezed into high-traffic urban areas on small lots. So as the new millennium approached, embassy bombings, like those in Kenya and Tanzania in 1998, demonstrated the need for a new standard. In 2003, DOS revised its standard to meet this new threat.

The 2003 standard limited penetration concerns to 3 feet and reconstituted the standard from a gasoline to a diesel truck. Other agencies — like the Department of Defense (DOD) and Department of Energy (DOE) — found the new standard useful…but incomplete.

DOD, for example, kept the original penetration ratings from the 1985 standard, which acknowledged the potential for bombings outside a 3-foot range. (Military bases are typically surrounded by wide open spaces, which create a much greater stopping distance for enemy vehicles.)

“Other concerns cropped up as well,” says Alberson. “The 2003 standard assumed a terrorist would use a 2.5-ton diesel truck to carry out an attack. But recent realities in Iraq, Afghanistan and other countries make it clear that practically any vehicle will do.”

The U.S. Army Corps of Engineers wanted a more flexible standard, so ASTM created a team in fall 2003 to address their need. Led by Alberson, the team developed ASTM F2656-07, Standard Test Method for Vehicle Crash Testing of Perimeter Barriers, that reintroduces more penetration ratings, adds design flexibility to cover a wide range of vehicles and specifies different impact velocities for some vehicle categories.

To meet the standard, vendor barriers must be tested by an accredited laboratory like TTI‘s Proving Ground Research Facility. The facility then issues a mandatory report on how the equipment performed. DOS adopted ASTM F2656-07 in October 2008 and activated it Feb. 1, 2009.

“The leadership role that TTI had in the development of this consensus test standard will ultimately help ensure the protection of American lives at home and abroad,” acknowledges Ed Conrath, a senior principal with Protection Engineering Consultants. Conrath oversaw ASTM F2656-07 development.