The in basket: We’ve been exploring the workings and
practicality of cable median barrier in Road Warrior this week.
I asked what commends it over other kinds of barrier and why it’s
usually installed close to one pair of lanes rather than in the
middle of the median. In a few places, it is put on both sides of
the median
The in basket: We’ve been exploring the workings and practicality
of cable median barrier in Road Warrior this week.
In addition to the areas covered (Wednesday?) I asked what commends
it over other kinds of barrier and why it’s usually installed close
to one pair of lanes rather than in the middle of the median. In a
few places, it is put on both sides of the median
The out basket: Lisa Murdock of the Olympic Region of state
highways said cable median barrier flexes up to 12 feet, allows
drivers to safely stop the vehicle without re-entering traffic,
allows water to pass underneath and is best in conjunction with
wide medians
Normal guardrail flexes up to three feet. allows drivers some
control after impacts, lets water pass beneath it and is often used
above steep slopes.
Concrete barrier has little or no flexibility, often redirects cars
back into traffic and is best where traffic moves in opposite
directions in close quarters, where there’s no room for a
median.
“Occupants of vehicles striking cable barrier are less likely to be
injured or killed than those striking concrete barrier or
guardrail,” she said. “This is partly because cable barrier is far
less likely to redirect an errant vehicle into a second vehicle in
the collision.”
“Statewide, cable barrier successfully restrained 95 percent of
errant vehicles without involving a second vehicle. In comparison,
only 67 to 75 percent of crashes with W-beam guardrail and concrete
barrier (did). When one vehicle crashes into another during a
collision, the risk of injury and the number of injuries
increase.”
The median’s slope and wetlands or dangerous obstacles in the
median dictate installation on the shoulders, rather than the
middle, she said.
“In locations where there is nothing in the median, but cable
barrier is on both sides, it’s because we installed the cable
barrier less than 10 feet from the fog line to avoid wetlands. This
cable barrier can flex up to 10 feet. We didn’t want cars crossing
the median and having the cable barrier flex into the oncoming
lanes.” Having it on both sides helps prevent that.
