ATSSA Signal March/April 2019

American Traffic Safety Services Association 20 Innovation & New Programs In an effort to mitigate and reduce the occurrence of Roadway Departure (RwD) crashes, numerous state and federal transportation agencies have developed strategies and countermeasures to ad- dress this nationwide issue, which ac- counts for 52 percent of all traffic fatal- ities in the United States, according to the Federal Highway Administration (FHWA). Public agencies are actively tackling the challenge of RwD crashes. RwD crashes are a focal point in a number of strategic highway safety plans, in- cluding those of South Carolina’s De- partment of Transportation (DOT) and Delaware’s DOT. “RwD crashes are a major concern with- in the roadway safety industry,” said ATSSA Director of New Programs Brian Watson. “Numerous transportation agencies and organizations have shift- ed their focus to address these types of crashes—developing and implement- ing various countermeasures to miti- gate injuries and greatly reduce traffic fatalities. ATSSA recently published a case study, ‘Preventing Vehicle Depar- tures from Roadways,’ that directly ad- dresses this incident. Our association intends to continue providing informa- tion in hopes of countering this nation- wide problem.” According to the FHWA, crashes that occur after a vehicle crosses an edge or center line (trailing from the travel lane) resulted in an average of 19,233 traffic fatalities from 2015 to 2017. Safety Specialist for the Roadway De- parture Team at the FHWA’s Office of Safety Design Cathy Satterfield, P.E. said the most effective way to reduce RwD crashes is through a systemic deploy- ment of proven countermeasures. “That doesn’t mean placing every counter- measure on every mile of road,” Satter- field said. “It means using crash data along with other information we have about the roadway and applying low- cost countermeasures at the locations based on the conditions that exist and the types of crashes occurring there.” Satterfield said those conditions might include the curvature of the road, the amount of traffic on the road, the width of the road, or other factors. The na- tionwide data FHWA has examined shows that the most severe lane de- parture crashes tend to be in rural ar- eas, and the most harmful incidents typically involve a head-on crash, a rollover, or a collision with a tree. FHWA has also found that some of the lowest-cost lane departure countermea- sures are also the most effective at pre- venting drivers from leaving their lane or the roadway. Satterfield said these include signs, pavement markings, rum- ble strips, and friction treatments. Ad- ditionally, applying Safety EdgeSM, a pavement countermeasure that slopes the edges of roadways to lessen verti- cal drop-off, provides a better chance for a driver who has left the roadway to be able to recover from departure. Other countermeasures include shoul- ders, clear zones, and traversable slopes. Satterfield said while they are all critical, they come at a high price. However, higher-cost countermeasures, which also include breakaway supports on signs, lights and utility poles, and bar- riers and crash cushions, are important to reduce the severity of roadway de- parture crashes, especially when the other countermeasures aren’t feasible or didn’t prevent the RwD. These higher cost countermeasures are typically re- served for locations with higher risk. “None of the countermeasures are par- ticularly new, but they have not been systemically deployed everywhere they are needed,” Satterfield said. “There are some new variations on some of these countermeasures.” Satterfield said some examples of these new variations include new rumble strip designs that create less noise and can be used more widely, and utility poles with an energy-absorbing design that can lessen the severity of a crash. De- sign modifications, along with systemic analysis, are key to public agencies get- ting these countermeasures out on larg- er portions of the roadway network where they are needed to reduce RwD accidents. Other innovations Satterfield said are important to factor in include Connect- ed Automated Vehicles (CAVs), which will make a difference on how public transportation agencies design their infrastructure to make it work more ef fec tively to accommodate new technologies. According to Satterfield, Local Road Safety Plans (LRSPs) are another inno- vation the FHWA believes will make a difference. The Minnesota Department of Transportation (MnDOT) has devel- oped data-driven systemic plans for ev- ery county in the state and targeted half the available safety funds for projects from these plans, since half the crashes were occurring on the county system. Since widespread deployment of the strategies in the plans began in 2012, the fatality rate on the county system has been declining, Satterfield said. Oth- er states are trying to replicate Minn- DOT’s plan. Washington State’s Local Technical Assistance Program (LTAP) has provided its counties with crash data, formatted to help county engineersmore Reducing roadway departure crashes How some public agencies and manufacturers are working to develop countermeasures