On Wednesday afternoon, Eric Moore turned his white sport utility vehicle from Kentucky Street east onto Seventh Street, then immediately made a left turn into a drive-through mail drop lane.

Then he drove right past a sign informing him that such maneuvers will soon be prohibited.

“This is the first time in five years that I lived here that I’ve made that left turn, and that’s because I forgot to mail this,” Moore said, brandishing a stamped envelope. “I’ll probably never use it again.”

He may not get the opportunity. On March 18, the city will put in a “safe lane divider” at the intersection to prevent left turns from eastbound Seventh Street to the line of letter boxes along Kentucky, behind the post office.

City Traffic Engineer David Woosley said officials believe left turns into the letterbox lane are a culprit for several problems. Such configurations, with the lane entrance only a few feet from the intersection, are generally a no-no in traffic planning.

“It causes congestion at the intersection,” Woosley said. “And it may be responsible for some accidents there as well.”

The intersection of Seventh and Kentucky has been the site of 25 accidents some injurious, none fatal in the last three years, Woosley said. That’s a high rate, he said, for intersections with similar levels of traffic.

The divider, Woosley said, is essentially a rubber curb with vertical posts that will obstruct left turns. The city will review the performance of the device in about six months.

Lawrence Postmaster Bill Reynolds was unavailable to comment on how the device will affect post office business, and other postal employees declined comment.

It seems certain to affect postal customers, however. During a 10-minute stretch Wednesday afternoon, three vehicles made left turns into the lane. Just two drivers made right turns.

At least one driver will be glad to see the left-turn ban.

“I almost rear-ended somebody (who was) doing that,” said Caterina Benalcazar, a Lawrence resident. “You barely have time to signal when you’re turning right, then left. It’s a lightning-fast situation.”