hmmm, found some trivia but not where the term came from
http://www.dot.ca.gov/newtech/operations/roadsidesafety/staking/index.htm
Jersey Barriers or Jersey Curbs.
Many people recognize the "Jersey Curb" as that unattractive and artless piece of concrete that separates traffic lanes and acts as a bridge rail. It is called a "Jersey Curb" since it was actually developed in New Jersey along the Turnpike in the late 1950s and 1960s. Interestingly, it was based on an innovative concrete divider the California Division of Highways placed on Grapevine Grade in the middle of US 99. They called this divider a "parabolic concrete barrier" since it was designed to deflect trucks who had used previous dividers to aid their braking by rubbing against them. It was two feet tall, more squat than the present incarnation and consisted of 20 foot lengths each weighing about a ton.
The value of such a barrier for preventing accidents was immediately obvious and the present form appeared in the mid-1960s. In fact, the first Jersey Curb to be used in California was placed down the middle of the Harbor Freeway (I-110) in the late 1960s. By the end of the 1970s it was used for all bridge rails and for dividing urban freeways. In my estimation, any questions of its effectiveness were addressed when the "tank guy" in San Diego back in 1995 tried to cross one on the SR-163 Freeway to go into oncoming traffic. The sizable tank could not scale it and further caused relatively little damage. If these barriers can stop a tank, then they must be good enough to stop errant cars. Efforts have been made to soften their stark appearance with decorations ranging from a groove on the outside part of the bridge rail to elaborate designs, some of which hark back to the days of the "mission style" concrete guardrails.
Also known as "K" Rail.
some math:
http://duteela.et.tudelft.nl/~wout/output/ISCAS2003_Tasic_K_rails.pdf#search=%22%22k-rail%22%20name%22