Every single day, millions of drivers hit the road in a rush to get to work, pick up their kids, or just to complete simple errands. While speeding a little bit may seem harmless, the reality is far more dangerous than what meets the eye.
There are a slew of common injuries resulting from speeding accidents and it’s well known that speeding is one of the leading causes of crashes on the roads in the United States.
Speed limits are meticulously calculated to save lives as opposed to being pointless numbers on signs. Explore the ins and outs of why speed limits exist, the science behind them, and how they play a critical role both in keeping you safe and in preventing accidents.
The History of Speed Limits
The concept of speed limits goes back to around the late 19th century when motor vehicles were first being introduced to public roads. Speed limits of 12-15 miles per hour depending on if you were in the city or rural roads were quite common. As technology advanced, though, so too did speed limits which resulted in federal guidelines due to increased fatalities and fuel shortages.
Studies slowly began to reveal that implementing and enforcing speed limits drastically reduced accidents and fatalities. In fact, in 1974 when the U.S. reduced the national maximum speed limit to 55mph to save energy, fatalities dropped by a wide margin. Evidence such as this cemented the role that speed limits play in road safety and soon resulted in widespread legislation which impacted the speed at which drivers could move.
How Speed Affects Accidents Severity
The major reason speed limits exist is that there is a direct correlation between the speed of a vehicle and the severity of injuries received in a crash. This should come as no surprise. When a vehicle’s speed just doubles it’s kinetic energy quadruples. This force is that which is delivered upon a collision with another vehicle. This simple law of physics alone explains why two crashes, at what seems like similar speeds, can have such drastically different results.
For perspective, at slow speeds of 15-20 miles per hour, a person has a near 90% chance of survival, whereas they have a 90% chance of death at 40 miles per hour. For vehicle-on-vehicle crashes, a minor fender bender at around 15mph may result in just a scratched bumper whereas a 60mph head-on collision will likely result in severe injury or death. This difference underscores the importance of adhering to speed limits and why they actually matter.
The Role of Human Reaction Time
Even the most attentive of drivers need adequate time to recognize and respond to hazards. The average perception time for drivers on the road is around ¾ of a second, but for drivers with less experience it can be as long as 1.5 seconds which is a drastic difference. At a speed of 30 miles per hour, a vehicle can go around 44 feet per second. This means that if you have a slower reaction time of 1.5 seconds, the vehicle could cover 66 feet before you would react. At a speed of 60 miles per hour, that car can cover a distance of 88 feet per second or 132 feet before you can react.
For perspective, 66 feet is roughly the length of a bowling alley whereas 132 feet is about 3/5ths the length of a 747 plane’s wingspan. Higher speeds also lengthen braking distances, with a car traveling 60 miles per hour needing twice the stopping distance as a car traveling 30 miles per hour. These factors drastically reduce the margin for error which makes high-speed driving inherently riskier.
The Intersection of Road Designs and Speed Limits
Speed limits aren’t just arbitrary numbers, rather they are carefully selected based on the design of a road and the intended use of that road. Engineers consider a variety of factors when determining speed limits, such as the road width, visibility, traffic volume, pedestrian crossings, and more.
To add perspective, residential streets that have narrow lanes, parked cars, and a lot of pedestrian activity have lower speed limits due to more risk factors and less reaction time for drivers. Highways, on the other hand, are designed for faster travel as they have wider lanes, greater field of vision, and fewer obstacles. By making the choice to ignore these speed limits, you simply put everyone’s lives at risk.
Exceeding the speed limit on a residential street can create a much higher likelihood of colliding with a pedestrian or cyclist, whereas speeding on the highway increases the likelihood of severe multi-vehicle pileups.
Common Myths About Speed Limits
Despite the fact that it has been proven time and time again that speed limits save lives, there are still some misconceptions surrounding them that are worth clearing. Perhaps the most common is that some people believe speed limits are a way for local governments to generate revenue through fines. It’s important to remember that speed limits are in place for safety reasons, rather than to be a cash grab.
Another common misconception is that driving just a few miles over the speed limit is harmless due to the small difference in the number. While you may not get a ticket for going five miles per hour over the limit, your stopping distance can increase drastically which can be the difference between avoiding a collision or causing one.
Obey speed limits to save lives
Speed limits are about more than just some silly numbers on a sign that change. Rather, they are a critical part of road safety and should be followed to the number. From their historical origin to the science behind accidents, it should be clear why these numbers are set where they are. Always remember that the ultimate goal of a speed limit is to protect lives, so the next time you’re tempted to put the pedal to the medal remember that even a small increase in speed can drastically increase your risk of an accident. By respecting a speed limit you aren’t just respecting the law, rather you are playing an active role in making roads safer.
