Median Barriers
FHWA Recommends Ready-to-Use Safety Technologies
Median Barriers - A proven safety technology that prevents deadly, median crossover head-on crashes.
Median Crossover Head-On Crashes
In 2001 there were 23,139 road departure fatalities, accounting for almost 55% of all roadway fatalities. Of this total, 16,214 fatalities were from run-off-the-road (ROR) crashes, which comprise 38.5% of all fatalities.
Also, there were 740,000 road departure injury crashes (35% of all injury crashes) and 2,600,000 road departure crashes (40% of all crashes) in 2001.
On the freeway system, there were 267 fatalities involving crossover median head-on collisions – a number which may seem small in comparison to the statistics listed above.
But these are extremely dangerous and tragic crashes. In fact, these crashes are 3 times as severe as other highway crashes. It is the extreme severity of these fatalities and injuries, as well as the fact that many of these are innocent victims that tells the real story.
Putting It In Perspective (2001)
- There is one crossover fatality for about every 200 freeway miles.
- An average of 250 people are killed annually in freeway crossover crashes.
- Median crashes are 3 times more severe than other highway crashes*
*Statistic from NCDOT
Why Are Median Crossover Head-On Collisions So Deadly?
Due to the extraordinary growth of traffic and congestion on today's freeways, when a vehicle leaves the road and crosses the median, there is a high probability of hitting one or more oncoming vehicles if there isn’t a median barrier.
And unfortunately, many freeways do not have median barriers to prevent these catastrophic median crossover collisions.
When many of the early freeways were built, these freeways, including the median width, were designed for forecasted volumes. No one anticipated the current high level of traffic volume and the need for median barriers.
However, traffic volume and traffic congestion increased far beyond the forecasted levels. In order to improve mobility, new lanes were often added by narrowing median widths even further.
So today, with the higher traffic volumes traveling at high speeds, and narrow medians without barriers, median crossover head-on crashes are occurring with increasing frequency and deadly results.
FHWA RECOMMENDS THE USE OF MEDIAN BARRIERS: A proven safety technology that prevents deadly, median crossover head-on crashes.
What Does A Median Barrier Do?
Median barriers are designed to prevent vehicles from crossing the median and going into opposing lanes.
There are different types of median barriers (concrete, steel, and cable) and all are designed to safely stop or redirect a vehicle that enters the median.
The most commonly used median barrier in urban areas is the concrete Jersey barrier. Metal beam and cable barriers are commonly used in rural areas.
What Kind of Median Barrier Should Be Used?
In order to determine what type of median barrier should be used, highway engineers assess a number of factors including: traffic volume and speed; traffic vehicle mix; median width and cross slope; number of lanes; roadway alignment; crash history; and installation and maintenance costs.
SCDOT Success Story – 99% Effective
In 1999-2000, more than 70 people in South Carolina lost their lives in 57 separate interstate media crashes.
To address this problem, SCDOT, using 100% federal-aid funds from FHWA, installed 314.5 miles of three-strand median cable on all interstate segments with medians less than 60 feet wide.
Over the next three years, the results of this installation showed that 1,913 vehicles were stopped by the median barriers. Only 15 vehicles – less than 1 percent of those that penetrated the median – also penetrated the cable barrier, resulting in 8 median crossover fatalities.
Put another way, the installation of these cable media barriers were 99% effective in saving lives.
NCDOT Success with Median Barriers
In January 2003, the North Carolina Department of Transportation (NCDOT) announced that its median barrier safety program, called Across the Median Safety, saved almost 70 lives and prevented hundreds of injuries.
Established in 1998, this program has installed about 730 miles of median barriers on full-access highways – with median widths of 70 feet or less -- that have a record of crossover crashes. NCDOT plans to install another 1,000 miles by the spring of 2004.
Benefits of Median Barriers
- Proven, Effective Safety Solution
- Cost Beneficial
- Variety of Median Barriers To Address Specific Situations
Federal Standards for Median Barriers
FHWA requires that all roadside hardware such as median barriers used on the National Highway System meet the federal standards contained in the National Cooperative Highway Research Program (NCHRP) Report 350,"Recommended Procedures for the Safety Performance Evaluation of Highway Features."
For More Information, Contact:
Richard Powers, FHWA Office of Safety
Phone: 202-366-1320
Email: Richard.Powers@fhwa.dot.gov
