UPS truck drivers don't take left turns, and despite this usually resulting in longer route, they are saving millions of dollars in fuel costs. From a report:
The company decided on eliminating left turns (or right turns in left-hand driving countries such as India) wherever possible after it found that drivers have to sit idly in the trucks while waiting to take the left turn to pass through traffic. So, it created an algorithm that eliminated left turns from drivers' routes even if meant a longer journey.
This meant that drivers do not have to wait in traffic to take a left turn and can take the right turn at junctions. Of course, the algorithm does not entirely eliminate left turns, but the number of left turns taken by UPS trucks is less than 10 percent of all turns made. Turns out that UPS was right -- the idea really paid off. In 2005, a year after it announced that it will minimize left turns, the company said that the total distance covered by its 96,000 trucks was reduced by 747,000km, and 190,000 litres of fuel had been saved.
In 2011, Bob Stoffel, a UPS Senior Vice President, told Fortune that the company had reduced distance traveled by trucks by 20.4 million miles, and reduced CO2 emissions by 20,000 metric tons, by not taking left turns. A recent report by The Independent says that the total reduction in distance traveled by UPS trucks now stands at 45.8 million miles, and there are 1,100 fewer trucks in its fleet because of the algorithm. Even by conservative estimates, that's tens of millions of dollars of savings in fuel costs.