Safety

Introduction

Safety on the road goes beyond responsible driving practices — Americans want their roads to be well-maintained to ensure a safe, smooth ride. When pavement is rough, uneven, or made hazardous by weather conditions, drivers and their families may be put at risk. In fact, in 2010 32,885 individuals died in the U.S. as a result of poor roadway conditions.1 The total cost of crashes, in terms of medical, workplace, legal, and administrative costs, emergency services, lost wages, and lost lives, in the country is nearly $3 billion.2

Substandard roads can cause a loss of vehicle control, driver fatigue, and an increase in frequency of lost-load accidents.3 As pavement serviceability decreases and roughness increases, traffic-related crashes are also likely to increase.4 For these reasons, keeping roads in a state of good repair and ensuring a smooth pavement with a high level of performance is important. Easy-to-maintain asphalt is the pavement of choice for safety. It provides drivers with a smooth, skid-resistant surface, excellent gripping power, and ultimately, a safer ride.

Key Pavement Technologies

Asphalt is the best pavement option for hazardous weather conditions. For example, one type of asphalt surface, known as open-graded friction course (OGFC), allows rainwater to drain through the surface layer and off to the sides while still providing good skid resistance.5 This reduces the amount of splash and spray produced by vehicles, improving visibility and safety.

Surfaces paved with open-graded asphalt have been shown to greatly reduce traffic accidents and related fatalities. For example, in the mid-2000s, the Texas Department of Transportation placed an open-graded asphalt surface on several roads with a high accident frequency. A year later, despite a large increase in rainfall, the roads experienced a significant decrease in crashes, injuries, and fatalities, likely due to the improved skid resistance, reduced splashing and improved visibility.6

 

OGFC pavements reduce roadspray during rain events. Watch as visability improved as soon as the vehicle moves from a dense-graded pavement to an open-graded one.
 

Also, because asphalt pavements are generally darker in hue, they require less salt or other deicing treatments to ensure clear winter roadways compared to light colored pavements7,19 In fact, at pavement temperatures below 15°F, the use of deicing salts on snow-covered roadways and bridges are not as effective and additional chemicals are often required,8 which can have a negative environmental impact.9 When deicers are needed, they generally do less damage to asphalt pavements than other road surfaces.10

The darker color can also provide greater contrast with white and yellow stripes, increasing the visibility of pavement markings.11 All types of pavement marking systems can work well on asphalt pavements,12 and there is evidence that markings remain effective longer on asphalt13 even in heavy snow areas.14 For thermoplastic markings, in particular, asphalt pavements provide a tighter, stronger bond than concrete pavements.15

Emerging Research

A National Cooperative Highway Research Program (NCHRP) study found that 13.5 percent of fatal crashes and 18.8 percent of all crashes occur when the pavement surface is wet.16 These findings have increased industry emphasis on ensuring the pavement surface are maintained to ensure a safe driving experience. In 2013, the Louisiana Transportation Research Center prepared a technical report for the Louisiana DOT highlighting the use of OGFC mixtures to enhance safety and performance. The report finds that the primary benefits of OGFC asphalt pavements are improved safety, driver comfort and environmental benefits resulting from smoother pavements, which increase fuel economy and reduce pavement noise.17 OGFC pavements reduced hydroplaning, pavement glare and splash/spray, which led to an increase in driver confidence.17

Drivability

Asphalt is the answer to building and maintaining smooth, good roads for safety. From technologies like open-graded asphalt pavements to natural attributes like strong gripping power and skid-resistance, asphalt provides drivers with an even, smooth surface that can keep them and their families safe. Using open-graded asphalt has been proven to reduce traffic accidents and related fatalities, and asphalt pavements typically require less deicing treatments than other pavements.

Because asphalt pavements are quick to construct and easy to maintain, they can be kept smoother and safer more cost-effectively over the years. Asphalt’s naturally smooth and skid-resistant surface18 helps to maintain quality roadway conditions and reduce the cost of maintaining your vehicle.

Sources

  1. ASCE (2013). Roads. 2013 Report Card for America’s Infrastructure. American Society of Civil Engineers, Washington, D.C. 

  2. Cambridge Systematics Inc. (2011). Crashes vs. Congestion — What’s the Cost to Society. AAA, Washington, D.C. 

  3. Miller, T.R. and E. Zaloshnja (2009). On a Crash Course: The Dangers and Health Costs of Deficient Roadways. Pacific Institute for Research & Evaluation, Calverton, Maryland. 

  4. Jiang, X., B. Huang, R.L. Zaretzki, S. Richards, and X. Yan (2013). Estimating Safety Effects of Pavement Management Factors Utilizing Bayesian Random Effect Models. Traffic Injury Prevention, Vol. 14, No. 7, pp. 766–775. 

  5. Putman, B.J. (2012). Evaluation of Open-Graded Friction Courses: Construction, Maintenance, and Performance. Report FHWA-SC-12-04. Clemson University, Clemson, South Carolina.

  6. Rand, D. (2006). TxDOT’s Use of Permeable Friction Courses (PFC). Presented at Arkansas Quality Asphalt Conference, January 5–6, 2006, Little Rock, Arkansas. 

  7. TranSafety (1997). Using Salt and Sand for Winter Road Maintenance. Road Management & Engineering Journal. 

  8. MnDOT (2013). MnDOT District 1 2013 Winter State Highway Maintenance White Paper — Fact Sheet. Minnesota Department of Transportation, St. Paul, Minnesota. 

  9. Langen, T. A., M. Twiss, T. Young, K. Janoyan, J.C. Stager, J. Osso Jr., H. Prutzman, and B. Green (2006). Environmental Impacts of Winter Road Management at the Cascade Lakes and Chapel Pond. Clarkson Center for the Environment, Clarkson University, Potsdam, New York.

  10. Sumsion, E.S., and W.S. Guthrie (2013). Physical and Chemical Effects of Deicers on Concrete Pavement: Literature Review. Report UT-13.09. Utah Department of Transportation, Salt Lake City, Utah. 

  11. Debaillon, C., P. Carlson, Y. He, T. Schnell, and Fuat Aktan (2007). Updates to Research on Recommended Minimum Levels for Pavement Marking Retroreflectivity to Meet Driver Night Visibility Needs. Report FHWA-HRT-07-059. Federal Highway Administration, McLean, Virginia.

  12. Masliah, M., G. Bahar, T. Erwin, and E. Tan (2005). Towards Improved Management of Pavement Markings and Markers. Presented at the 2005 Annual Conference of the Transportation Association of Canada, Calgary, Alberta.

  13. Migletz, J., & J. Graham (2002). NCHRP Synthesis of Highway Practice 306: Long-Term Pavement Marking Practices. Transportation Research Board of the National Archives, Washington, D.C.

  14. Lynde, McG. (2006). Evaluation of Inlaid Durable Pavement Markings in an Oregon Snow Zone. Report FHWA-OR-DF-06-10. Oregon Department of Transportation, Salem, Oregon.

  15. TxDOT (2004). Pavement Marking Handbook, Revised August 2004. Texas Department of Transportation, Austin, Texas.

  16. Dahir, S.H. and W.L. Gramling. 1990. Wet-Pavement Safety Programs. NCHRP Synthesis of Highway Practice 158. Transportation Research Board, Washington, DC.

  17. King Jr., W., Md.S. Kabir, S.B. Cooper Jr., C. Abadie (2013). Evaluation of Open Graded Friction Course (OGFC) Mixtures. Report FHWA/LA.13/513. Louisiana Transportation Research Center, Baton Rouge, Louisiana. 

  18. Gee, K.W. (2005). Technical Advisory: Surface Texture for Asphalt and Concrete Pavements. T 5040.36. Federal Highway Administration, Washington, D.C. 

  19. Cuelho, E., J. Harwood, M. Akin & E. Adams (2010). Establishing Best Practices for Removing Snow and Ice from California Roadways: Final Project Report. Western Transportation Institute, Montana State University – Bozeman, Bozeman, Montana.