For most families in North America, owning at least one car is the norm, and driving has become an everyday task. So much so, in fact, that it often transforms into a routine, requiring little thought or concentration. This sense of familiarity can lead to risky behaviors behind the wheel—texting, eating, daydreaming. But among these common distractions, there’s a phenomenon that doesn’t always get the attention it deserves: speed renormalization.
This psychological effect occurs when drivers leave a fast-paced freeway and enter slower traffic, or vice versa. Their perception of “normal speed” gets distorted, and they often unconsciously misjudge how fast they’re going. For example, when transitioning from highway speeds to slower roads, drivers may feel they’re going slower than they really are, while drivers moving at a lower speed may perceive higher speed limits as being safer than they actually are.
The Science Behind It
Professor George Mather, a Vision Science expert at the University of Lincoln, led a study into this very phenomenon. The research focused on how short bursts of exposure to different speeds can warp our sense of what “normal” speed should feel like.
In the study, participants watched a slowed-down video of human motion, and then were shown a normal-speed version. Strangely, they perceived the normal-speed video as unnaturally fast and requested that it be slowed down to appear “normal.” This shows how our brains can quickly adjust to certain speeds, but it also exposes our tendency to misjudge those speeds after prolonged exposure.
The Impact on Drivers
This adaptation effect is exactly what happens to drivers after driving at a high speed for a while. The transition to a slower speed feels unnatural, and they may approach a ramp or turn too quickly without realizing it. Inversely, moving from slower traffic to a faster highway can make drivers feel as if they’re driving too slowly. It takes time for the brain to readjust, so it’s important for drivers to regularly check their speed, especially when transitioning between zones with different speed limits.
Given that driving is so routine for many, it’s easy to forget the inherent dangers involved—thousands of pounds of metal hurtling down the road at high speeds. But, as Professor Mather’s research demonstrates, external factors influence how we perceive danger on the road. These mental blind spots contribute to over 37,000 fatalities each year in the U.S. alone, with speeding-related crashes being responsible for over 9,000 deaths annually, not to mention countless injuries.
This disconnect between perceived and real danger is more prevalent than we realize, whether it’s speeding on highways or interacting with pedestrians, forklifts, or other moving equipment. Driving should always be approached with undivided attention—especially when it comes to speed. The speedometer exists for a reason, and checking it regularly should become second nature, particularly when transitioning between different speed zones.
