| Cable
Median Barriers |
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last updated December 23, 2021 |
Back
in the early
2000s, there were a number of serious head-on
collisions on San Antonio area freeways that had no center median
barrier. After a rash of these along Loop 1604, TxDOT installed
portable concrete Jersey barriers in the median of 1604 and announced
that they would be installing cable barriers in the medians of
other area highways as part of a statewide effort to do so.
As
often
happens, the second-guessing began
almost immediately. Skeptics bellowed that the "flimsy" barriers
wouldn't even stop a Yugo,
let alone an 18-wheeler. But engineers defended the barriers
and insisted that they would work as intended. And indeed, in the first
two years that cable
barriers were in place in the San Antonio area, they stopped every
single vehicle that hit them, including an 18-wheeler on I-35 in Von
Ormy.
A
before-and-after study in 2007 after 335 miles of cable
barriers were installed around the state showed that the number of
fatalities on
those roads where the barriers were installed dropped from 52
fatalities in the year before installation to just one
fatality
in the year afterward. In short, the barriers work and work
well.
In
fact, cable barriers are often better than metal guardrails and
concrete
Jersey barriers because they absorb more of the energy of the impact
than do
those traditional barriers, thus reducing the chance of injury and
death. They
also reduce the number of "rebound" accidents where a vehicle hits the
barrier and then bounces-back into the traffic lanes. All of these
benefits come at an installation cost that is typically about 25% the
cost of
concrete barriers and half the cost of metal guardrails, and repair is
typically faster and easier than with other barriers.
Successful cable-barrier capture of an 18-wheeler
(Source:
Washington
Department of Transportation)
One
understandable concern is what happens to motorcyclists who hit the
barrier. It would seem to be common sense that the cables
pose a significant risk of injury to riders. This has led to some
motorcyclists referring to cable barriers as "cheese cutters".
However, several studies have been done in the US, Europe, and
Australia on this issue and have generally concluded that the
statistical evidence to date shows that cable barriers are no more
dangerous to motorcyclists than other barriers. So while they may not
be better for motorcyclists, they're generally not worse.
A
while back, a friend told me about a driver involved in a collision that sent her vehicle
into the cable barrier on I-10 near Boerne. She was upset because the
barrier had sliced into her car and had caused significant
damage. However, she was uninjured, and the barrier quite likely
saved her life or at least prevented serious injury. Had it not
been for the barrier, she almost certainly would have gone into the
oncoming traffic and
probably been struck head-on or T-boned by traffic going 70 mph.
Furthermore, her vehicle likely would have suffered equal
or greater damage if there had been a traditional guardrail or concrete
barrier
instead.
Cable barriers are now fairly commonplace along divided highways in Texas.
Other
sites of interest
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Cable median barriers
