Turns out left turns are not only riskier, they also waste gas. So UPS – optimization-obsessed logistics company that it is – got rid of them.

Via Priceonomics:

UPS engineers found that left-hand turns were a major drag on efficiency. Turning against traffic resulted in long waits in left-hand turn lanes that wasted time and fuel, and it also led to a disproportionate number of accidents. By mapping out routes that involved "a series of right-hand loops," UPS improved profits and safety while touting their catchy, environmentally friendly policy. As of 2012, the right turn rule combined with other improvements — for the wow factor, UPS doesn't separate them out — saved around 10 million gallons of gas and reduced emissions by the equivalent of taking 5,300 cars of the road for a year.

Describing the policy in a speech, the CEO of UPS told his audience, "I can see a few of you smiling out there, and I know what you may be thinking. But it really works."