At 11 points in northern Virginia, the familiar straight dashed lines on the road gives way to a series of zig zags. The unusual markings, the result of a pilot project from the Virginia Department of Transportation, are meant to alert drivers to be cautious where the Washington and Old Dominion (W&OD) Trail intersects with the road — and bicyclists and pedestrians frequently cross.
After a year-long study of this striping treatment, Virginia DOT officials say the markings are effective and should become part of the Manual on Uniform Traffic Control Devices — the playbook for American street designers.
VDOT found the zig zag markings slowed average vehicle speeds, increased motorist awareness of pedestrians and cyclists, and increased the likelihood that drivers would yield. They also noted that the effects of the design change didn’t wear off once motorists became used to the it — they still slowed down a year after installation.
VDOT says the results indicate that zig zag markings are a more cost-effective solution for conflict points between trails and high-speed roads than the current treatments: flashing beacons placed above the road or off to the side.
The zig zag concept was imported from Europe. It is currently used in only two other locations in North America: Hawaii and Ottawa, Ontario. It was one of more than a dozen European traffic management techniques VDOT zeroed in on to test locally.