A new law known as the "move - over rule took effect October 1, 2010.

When there is an emergency vehicle with flashing lights on the shoulder of the road, unless otherwise directed, a driver on a road that is wide enough should merge left.

If traffic won't allow the driver to merge before reaching the scene, the law calls for slowing to a "reasonable and prudent" speed that takes into account weather and road conditions.

A driver who is speeding in the lane asjacent to a traffic stop could receive separate tickets for the two violations.

For more on transportation, go to Michael Dresser's blog at Baltimoresun.com/getting there.