stop n' merge 

A technique employed by ignorant and/or terrified drivers when merging onto a freeway: instead of accelerating to merge into faster traffic, these drivers actually stop and attempt to cut into oncoming traffic from a complete standstill. The "stop n' merge" is a dangerous maneuver.

I almost got in an accident today because some clown decided to pull a stop n' merge in rush hour traffic.

stop n' merge by SLampy July 21, 2008