Four foot gap!

So the authorities in Pennsylvania are introducing a law to improve safety for cyclists:

HARRISBURG, Pa., March 28, 2012 /PRNewswire-USNewswire/ -- A law that sets new rules for Pennsylvania motorists to follow when encountering a bicyclist will take effect at 12:01 a.m. on Monday, April 2. The law, designed to improve safety and traffic flow, was signed by Governor Tom Corbett on Feb. 2.
The new law requires motorists to leave a 4-foot "cushion of safety" when passing a bicyclist. To achieve this cushion, drivers may cross a roadway's center line when passing a bicycle on the left, but only when opposing traffic allows.
Drivers attempting to turn left must also yield the right of way to bicycle riders traveling in the opposite direction.
"The differential in speed is the biggest safety challenge with motor vehicles and bicycles sharing our state's roadways," said PennDOT Secretary Barry J. Schoch. "I urge all drivers and cyclists to learn the rules of the road to better share our highways and make travel safer for all."
The new law also calls for bicycle riders to use all reasonable efforts to avoid impeding the normal flow of traffic. When there is only one travel lane, bicyclists may use any portion of the lane to avoid hazards on the roadway, including maintaining a safe distance from stopped and parked cars.
As always, bicyclists and motorists should obey all traffic signs and signals. PennDOT also recommends bicyclists always ride predictably and signal their intentions before proceeding so that motorists have a chance to react.