Here in the Norfolk, VA area we have a pair of H.O.V. (Carpool) lanes that run in the middle of the freeway (i.e. 3 east bound, 2 H.O.V. and 3 west bound lanes). These lanes are separated from the rest of traffic by a concrete barrier and the traffic direction can be changed to run either east or west depending on the amount of traffic. Each end of these lanes have a set of six drop down barricades similar to those used at railroad crossings to keep opposing traffic from entering the HOV lanes. There have been three instances where people have been driving the wrong way on the HOV lanes killing themselves and/or others.
The first was an Alzheimers patient that decided to enter the HOV and travel the wrong direction at one of the openings designed to allow emergency vehicles to enter.
The second was two days later when a drunk motorcyclist decided to make a U-turn after he had gotten onto the HOV lanes. He was killed when he was thrown off an overpass and landed on the freeway below.
The third was from a 70 year old who after smashing his way through the first 3 barricades, and carefully maneuvering around the other three, killing not only himself but the innocent driver that he hit.