Yes, it is not strictly a tool, but it has become ubiquitous. "K-rail" - California's version of the New Jersey Type 50 concrete barrier is inescapable if you are driving in this state.
There are a few reasons for this - it is fairly cheap over its lifespan, almost unbreakable, it doesn't kill people when they hit it at an angle (it lifts the car off the ground and slows it so it doesn't spin around or flip) and it is pretty effective at keeping the people behind the barrier safe. The basic shape is the result of observations made by New Jersey police 40-50 years ago. The past 20 years have seen an explosion in the use of it however.
There are improvements to the shape of the K-rail profile, in particular one called the "F-shape" in which the bottom section is not quite as steep. Crash tests show it is a bit better, but with hundreds or perhaps thousands of miles of this stuff already made and slipforms all set with the K-rail profile I don't see change coming anytime soon. Sometimes being good enough is good enough.
The yellow cans in the back are filled with sand in the upper portion. The bottom is typically empty. Since the K-rail isn't going to move, you need something on any exposed end to absorb any shock.
As an aside, the building in the background behind all these barriers is the Silicon Valley office of Microsoft.
Comments (3)
Strictly speaking, K-Rail is a temporary barrier with a slightly different shape from the extruded concrete Jersey barrier that CalTrans uses as a center divider on urban freeways. Newer CalTrans Jersey barrier appears to have a steeper angle on the sides and it is noticeably taller. Not much of it out there, though.
Further, I would argue that the Jersey barrier is quite likely to flip a car depending on the angle of approach. At high speeds, there have been occasions when cars have ended up on top of the barrier. In one such incident, Long Beach police officer's patrol car climbed the barrier and slid along the top into a very heavy duty sign upright [approx. 2-feet in diameter, anchored in concrete]. The speed was sufficient to exceed the elasticity of steel; the car was split in half, killing the officer. He was pursuing a suspect at high speed, approximately 90 mph.
The sand-filled barrels are the Fitch barrier, named for John Fitch, who played a huge role in making motor racing more safe from the 1960s up until his death a few years ago.
Posted by Bob | January 10, 2008 10:52 PM
Posted on January 10, 2008 22:52
What is the weight of 20ft. lengh of K-rail
What is the lifting capacity needed
Posted by Stuart Marsh | August 20, 2008 6:11 PM
Posted on August 20, 2008 18:11
I was thinking that a K-Rail gets its name because it weighs a thousand pounds .
Posted by Ronald W. Klimmek | January 16, 2010 11:39 AM
Posted on January 16, 2010 11:39