Speeding is the second leading cause of traffic fatalities after drunk driving. According to a 2005 study by the Insurance Institute for Highway Safety, “The relationship between vehicle speed and crash severity is unequivocal and based on the laws of physics.” There you have it: the faster you go, the more likely it is you’ll be pulverized in a crash. An object in motion, and so forth. Even though they may sometimes feel arbitrary, posted speed limits exist for a reason. The IIHS study also points out that the likelihood of a crash increases when a driver goes above or below the average speed on a given roadway. When everyone travels at the same general speed, things are more predictable, and the road is safer as a result.