Quicker Left Turns at a Signal

This driving tip ties in with the next one in the series, which will be titled "Pay Attention to the Gaps." There is a key to making quicker left-hand turns, but before we get there, let's go to what is typically done at signal controlled intersections when a car is waiting to turn left.

The diagram on the left displays Car C stopped at the mid-point of the intersection waiting for an opportunity to safely turn left. Car C waits for Car A to pass, but there isn't enough of a break before Car B arrives for Car C to make the left-hand turn.



Car C had to wait because they couldn't get a "running start" before making the turn. It takes most cars a second or two to move from a standstill to a speed of 5-10 MPH, time that Car C didn't have before Car B arrived in the intersection. A car traveling at 30 MPH covers 44 feet per second and it is likely that Car C would need 3 seconds to safely complete the left-hand turn and not cause Car B to break or swerve to avoid a collision, which means that Car B would have to be at least 132 feet away at the time that Car C hit the gas and started the turn. (The speed of the oncoming car changes the amount of time that Car C has to make their turn, faster means less time, slower means more time.)

Car C could have reduced the amount of time needed by waiting further back in the intersection and then starting to move forward--not turning yet--as Car A was approaching. (The other 3 diagrams show the relative positions of the cars using this strategy.) As Car C's speed increases and Car A safely proceeds past them, Car C--which is now in motion--can more quickly turn and clear the intersection without infringing on Car B's right of way.

Of course, it's possible to push the limits with this strategy and without realizing it cause Car B to break out of surprise or by just being cautious, so care should be taken to make this type of quick left turn only when circumstances dictate it can be accomplished safely.

Note: Don't forget about pedestrians, cyclists, cars turning right into the lane you will be headed towards, and if there are multiple lanes of oncoming traffic, make sure you can see any cars that might be blocked by Car A, especially if Car A is actually Truck A or other really big Vehicle A. Better slow and safe than sorry.