You might not use your handheld device while driving, but chances are you are doing something else which is also a leading cause of vehicle crashes in the United States: Failing to use your turn signals. That’s right. More than 2 million accidents every year are caused by drivers failing to signal when they turn or change lanes. According to the Society of Automotive Engineers, drivers either don’t use their signals when changing lanes or don’t turn the signals off nearly half the time. When actually making a turn the failure rate is a whopping 25%. That means 2 billion times a day drivers don’t use their signals, for an incredible 750 billion times every year. The other problem with failure to use turn signals is that police are much less likely to enforce their use than they are to enforce other safe driving laws. This might be due to their inability to detect whether or not drivers are signalling properly, or it might be because of the current emphasis on distracted driving and the ongoing enforcement of laws designed to control driving under the influence of alcohol. Some auto industry analysts have suggested that what is needed is a “Smart Turn Signal” device which reminds drivers to signal, turns off signals left running after a lane change has been completed and possibly even self-signal. This has some suggesting that what is needed is to take the full step to autonomous vehicles; cars which drive themselves, an effort already under way in some parts of the country. As a comparison, less than 1 million accidents each year are caused by distracted driving, making failing to signal a turn or lane change much more dangerous by comparison. However, it is also true that distracted driving crashes are much more serious and much more likely to result in a fatality while accidents caused by failing to signal are far less likely to be dangerous. But for now, drivers just need to use their common sense, drive defensively and use their turn signals.