Priceonomics - Is Every Speed Limit Too Low? 7min

Over the past 12 years, Lt. Megge has increased the speed limit on nearly 400 of Michigan’s roadways. Each time, he or one of his officers hears from community groups who complain that people already drive too fast. But as Megge and his colleagues explain, their intent is not to reduce congestion, bow to the reality that everyone drives too fast, or even strike a balance between safety concerns and drivers’ desire to arrive at their destinations faster. Quite the opposite, Lt. Megge advocates for raising speed limits because he believes it makes roads safer. ... This “nationally recognized method” of setting the speed limit as the 85th percentile speed is essentially traffic engineering 101. It’s also a bit perplexing to those unfamiliar with the concept. Shouldn’t everyone drive at or below the speed limit? And if a driver’s speed is dictated by the speed limit, how can you decide whether or not to change that limit based on the speed of traffic? ... The answer lies in realizing that the speed limit really is just a number on a sign, and it has very little influence on how fast people drive.