Zigzag lines painted on two Loudoun County roads appear to be serving their purpose and slowing down drivers in front of trail crossings, a study has found. The zigzags were painted in 500-foot stretches in front of W&OD trail crossings on two Loudoun County roads in April 2009 as a test to find ways of keeping bicyclists and walkers safer.

Though such markings dot roads in Australia and Britain, local researchers believe the Loudoun tests were the first of their kind in the United States.