Left turn problem while driving, on the one hand, is so common that most people won’t think about it; on the other hand, it is so complicated and “evil” that remains mainly unsolved and avoided.
UPS avoided it
The most famous no-left-turn application is probably demonstrated by UPS. It’s route planner system ORION, based on heuristic algorithm, told UPS drivers not to turn left. Since 2004, turning right, plus other efficiency-optimizing efforts, has saved about 10 million gallons of gas and reduced emissions equal to taking more than 5,000 cars off the road for a year. (UPS)
Accident Rate
According to the US National Highway Traffic Safety Association, turning left is a leading critical pre-crash event, and occurs in 22.2 percent of crashes.
Law
The driver making a left hand turn will only have the right of way if they are proceeding on a left-turn arrow.
Otherwise, the driver turning left at a green light must wait until all oncoming traffic is gone or far enough away to allow for a safe and complete turn.
If a traffic light is not present, the left turning driver must still abide by the same precautions. The oncoming traffic will have the right of way and do not have to stop or slow down to allow left-turning drivers to pass.
Drivers making left turns must also wait for all pedestrians and cyclists are safely across the street before they can proceed with the turn.
This is why it is rare to find the other driver at-fault for this type of accident, and can be even more difficult to prove.
However with that being said, like anything, there are always a few exceptions to the rule.
- The car driving straight was driving significantly over the speed limit when they were going through the intersection.
- The car that is driving straight ran a red light or stop sign.
- Unforeseen circumstances may warrant the other driver at-fault for the accident.
According to Price Benowitz blog
Selft-driving & Waymo
Self-driving car prototypes have been known to wait for long intervals at intersections before they finally made the left turn – heavily testing the patience of human drivers stuck behind them.
When a self-driving car hesitates at an intersection, the reason is not a problem with the algorithm but rather that the self-driving car finds that the safety margins for executing the turn are too small in the current situation: the risk is too high. Unfortunately, this problem can not be solved through better algorithms but only by increasing the level of acceptable risk! (driverless-future.com)
The Waymo vans have trouble with many unprotected left turns and with merging into heavy traffic in the Phoenix area, especially on highways. (The Information)