Tomorrow Mayor Vince Gray will issue a regulation clarifying that making a U-turn through the Pennsylvania Avenue bike lanes is in fact illegal.

The move, first noted by NBC4’s Adam Tuss, comes in the wake of revelations that the D.C. DMV was dismissing citations for the U-turns—which cyclists have long derided as dangerous—due to ambiguously worded rules regarding when the turns are legal and when they’re not. “We wanted to make it explicit,” said Pedro Ribeiro, Gray’s spokesman.

According to MPD data, of 14 reported bicycle crashes since the bike lanes were installed in 2010, 11 stemmed from drivers making U-turns. Last year, eight of 10 crashes in the lane were caused by cars making the turn.

In recent weeks, cyclists have banded together to demand that police more aggressively tickets drivers who make U-turns through the lanes, which run down the middle of Pennsylvania Avenue from Third to 15th streets NW. Two weeks ago Councilmember Tommy Wells (D-Ward 6) said he would introduce emergency legislation on December 4 clarifying that the turns are illegal.