Cable Barriers

In a continual effort to provide the safest roadways, the Nevada Department of Transportation has begun a program of installing cable barriers in the median of selected state roadways.

The effectiveness and safety benefits of cable barriers have been proven in Europe and much of the United States to help prevent the most serious of injuries from cross-median crashes. Approximately 13% of these cross-median crashes in Nevada are fatal, while over 50% of cross-median crashes result in injury.

The basic design of cable barriers consists of heavy-duty cables strung along a row of posts. The cables are tensioned to provide enough strength and give to safely catch misguided vehicles like a net, thus avoiding head-on collisions. Approximately 30 inches tall, the cable barriers are positioned low to efficiently catch most misguided vehicles around the vehicle chassis, grill and/or bumper and safely redirect them away from opposing traffic.

• Cable barrier rails can help prevent head-on collisions by catching misguided vehicles like a net and redirecting them in the median area.
• The design of cable barrier is more flexible than concrete barriers when struck, helping to diffuse the crash impact felt by vehicle occupants.
• If hit, cable barrier rails are relatively fast and easy to repair, allowing the Nevada Department of Transportation to quickly and cost-effectively return the roadway to its original condition.
• Immediately following an accident, and even prior to repairs, cable barriers often continue to provide protection against further head-on collisions.
• In the event of a crash that closes the roadway, cable barriers more easily allow for traffic to be re-routed through the median. This can help prevent roadside delays following traffic crashes.
• Cable barriers allow for proper roadside drainage.
• Cable barriers are often less expensive to install than other barriers, providing an effective transportation safety solution at less cost.

Cable barriers are not effective or appropriate for every roadway or situation. For instance, the design of cable barriers require a certain amount of space between the edge of the roadway and the barrier. Roadway speeds also impact the effectiveness and placement of cable barriers. High-traffic divided highways with larger medians are good candidates for cable barriers. The Nevada Department of Transportation conducts extensive surveys, considering such things as accident history, traffic speeds and volume, road grade and angle and size and slope of median to determine the safest, most effective safety measures for state roadways. With many rural roadways within the state of Nevada, there are less-traveled roadways that do not warrant the expense of cable barrier rail. Currently, the Nevada Department of Transportation has, or will, install cable barrier on U.S. 395 between Carson City and Minden, as well as on the Carson City Freeway.

Like all technology, cable barriers can not provide protection in every circumstance. Here are some important safety tips drivers can follow to help stay safe while driving:

• Obey all speed limits and traffic signs
• Wear seatbelts
• Adjust driving speeds as appropriate for weather and conditions
• Limit distractions while driving, such as cell phones
• Allow adequate space between your vehicles and other vehicles and objects
• Drive defensively
• Do not drive while sleepy or under the influence of alcohol or drugs

In late 2006, the Association of State Highway and Transportation Officials reported that only three states did not use cable median barriers at the time. Texas currently has over 600 miles of cable barrier, with another 200 miles planned. North Carolina has 550 miles of cable barrier. The Washington State Department of Transportation reported cable median barrier as costing between $130,000 to $300,000 per mile to install, as compared to the more-expensive $300,000 to $2.7 million per-mile cost of precast concrete barriers.

* National cable barrier information from “Cable Median Barrier” report compiled by the American Association of State Highway and Transportation Officials Technology Implementation Group.

American Association of State Highway and Transportation Officials – Technology Implementation Group