Turning left puts drivers against the flow of vehicles coming the other way, which leads them to wait 30–45 seconds each time with the engine running. A new routing system introduced a few years ago, which calculates routes favouring right turns, saves the whole UPS 10 million gallons (38 million litres) of fuel every year. On top of that, right turns are more safe, leading to only 1.2% of crashes instead of 22.2% for left turns.