Left-Turn Arrows

The Los Angeles Department of Transportation considers left-turn arrows at signalized intersections as one of its most popular requests. The left-turn arrows allow drivers to make left turns while opposing traffic is stopped.

The intersections with left-turn arrows differ from most other intersections in the City of Los Angeles. Most of the City’s intersections are “permissively” operated – meaning that left turns can be made whenever gaps occur in opposing traffic. The permissive operation may not be adequate at intersections such as freeway on-ramps, regional shopping centers and the intersections of two major streets. More direction, guidance may be necessary for motorists to maneuver safely through an intersection.

		Left-turn phasing is justified where:
		Not enough gaps occur in opposing traffic, causing excessive left-turn delays Left-turn lane traffic regularly spills into the through lane and the turn lane cannot be extended A significant number of left-turn accidents are reported Visibility is restricted between vehicles in the left-turn and through lanes An important transit route requires left turns and experiences delays Dual left-turn lanes cross opposing traffic The intersection has an unusual geometric alignment

Unnecessary left-turn arrows degrade overall traffic flow. Other motorists at an intersection must wait for longer periods during red signals in order to accommodate the left-turn arrow.

“Protected” left-turn arrows also cause motorists to wait at intersections. This arrow does not permit left-hand turns; even when adequate gaps in through traffic appear. Protected left-turn arrows should be used where necessary for safety purposes.

	LADOT often installs a “smart” left-turn arrow where there is clear justification for left-turn phasing. Under this “protected-permissive” left-turn phasing, the signal is green when only a few cars are waiting to turn left. If the number of cars waiting increases to four or five, a detector in the roadway will sense them and cause the arrow to be displayed.