Higher speed limits, like an entire bag of Hershey’s Kisses, are one of those things that sound good but really aren’t good for you. Politicians love them because they know people won’t oppose them. After all, who would object to being able to speed a bit more on the highway? It’s something we all do anyway, right?

The problem is that speeding is already a factor in 1 out of every 3 auto fatalities in the United States, which means that if you speed, or if someone else does, your life and the lives of your loved ones automatically become less safe. So why do we keep letting our elected leaders lead us into bad decisions?

Let’s take a look at speed limits throughout the US, what we know about how speed affects crash forces, and then tie this into what we can do to increase the safety of those we love on the road.

How are daytime speed limits distributed throughout the United States?

Speed limits throughout the US range from 60 mph in one state, Hawaii, to 85 mph in sections of Texas. Nevada, Idaho, Montana, Utah, Wyoming, and South Dakota are nearly as bad with PSLs (posted speed limits) at 80. The remaining states are mostly at 75 or 70 mph, with several New England states (New York, New Jersey, Delaware, Connecticut, Rhode Island, Massachusetts, Vermont) and Alaska at 65 mph.

How have speed limits changed over time in the US?

Speed limits have increased nearly uniformly throughout the states since 1995, when the National Highway System Designation Act repealed a 55 mph speed limit set by Congress in 1973. Prior to then, most states had had speed limits between 65 and 70 mph, and since then, particularly in recent years, many states have begun pushing ever higher speed limits, with potentially deadly consequences.

How do higher speeds increase the likelihoods of a crash?

Higher speeds make crashes more likely because there are finite limits on both human reaction times and vehicular braking times and distances. Research suggests human reaction times vary from moment to moment and situation to situation, but even using a conservative estimate of 2 seconds, a car stopping distance calculator and measurement comparer provides discomforting numbers:

At 20 mph, a speed at which 5% of pedestrians are likely to be killed when struck by a vehicle, 2 seconds of reaction time lead to 59 feet of “thinking” distance, or the time needed to see a hazard, decide to brake, and press the brakes. Beyond that, you also need 20 feet of braking distance, resulting in 79 feet of total stopping distance. That’s already more than the length of a semi-trailer and cab, or nine-tenths as long as the distance between bases in baseball.

How about at 40 mph? That’s a speed at which around 95% of pedestrians are likely to be killed when struck by a vehicle. It’s also a speed which the IIHS considers a severe crash when involving head-on collisions, and it’s the speed at which they conduct their moderate and small frontal overlap crash tests.

At 40 mph, 2 seconds of reaction time lead to 117 feet of “thinking” distance. Add 80 feet of braking distance, and you get 197 feet of total stopping distance, or nine-tenths the wingspan of a 747, or half the length of an NFL football field.

At 60 mph, which is slower than the highway PSLs in most states in the US (never mind the speeds people are actually reaching), it takes 176 feet just to *process* something enough to hit the brakes in 2 seconds. That’s already about the entire distance it takes to see, react, and stop before a hazard at 40 mph. However, things aren’t done there; you also need 180 feet of braking distance, which doubles your stopping distance and brings you to 356 feet.

That’s the length of a football field (NFL or soccer).

I don’t know if you’ve ever looked out at a football field and imagined not being able to avoid hitting a car parked at the end of it, but that’s a huge distance to deal with in an emergency situation.

At 80 mph, a speed legally permissible, at least in part, in 7 states, and a speed which many drivers in another 20 or so states regularly reach due to 70-75 mph limits, there’s practically no hope of avoiding an emergency. With 2 seconds of thinking time, you need 235 feet just to begin with, or a full 2/3rds of that NFL field / soccer pitch we just visualized, and another 320 feet to brake, bringing you to 554 feet, or around 1.5 football fields.

Why do higher speeds make collisions more likely to be fatal?

Higher speeds make collisions much more likely to be fatal because energy increases with the square of velocity. This is a fancy way of saying that increasing the speed of an object affects the force of a collision much more than increasing how much it weighs. It’s why being hit by a bullet shot out of a gun hurts a lot more (sometimes fatally more) than being hit by a bullet thrown at you.

Here’s a quick example with numbers thanks to a kinetic energy calculator:

At 20 mph, a prototypical mid-sized 3,200 lb car (e.g., a Toyota Camry) has 58,014 J of energy, or 58 KJ. At 40 mph, if energy increased linearly, we’d expect the Camry to carry 116 KJ of energy, or 200% as much as it did at 20 mph (due to 40 being 2 x 20).

However, it doesn’t.

Instead, it has 232 KJ, or 400% of (4x) the energy it carried when traveling at 20 mph. The speed was doubled, but the forces were quadrupled.

This is what it means for energy to increase with the square of the velocity. The energy in a collision increases much more quickly with speed than it does with weight. Or to put it simply, although the speed was merely doubled, the forces were quadrupled.

Our hypothetical Camry will be tested by the IIHS in what simulates a 40 mph collision with another Camry, resulting in a transfer of energy of 232 KJ. A Camry receiving a “good” frontal score is one that dissipated that energy without transferring so much of it into the driver that the driver dies. This, as I wrote before, is already considered to be a severe collision.

So what happens at highway speeds?

Well, at 60 mph, the Camry suddenly has 522 KJ of energy, or 900% of the energy it carried when traveling at 20 mph (rather than 300%, which you’d expect from 60 being 3 x 20). It has 225% of the energy it carried when traveling at 40 mph (rather than 150%, which you’d expect from 60 being 1.5 x 40).

To put it another way, the Camry needs to dissipate 9x as much energy at 60 mph as it did at 20 mph, or 2.25x as much energy at 60 mph as it did at 40 mph. Many people can’t handle receiving 225% as much energy as their vehicles are designed to protect them from, which is why there are many fatalities from head on collisions at 60 mph. Many of these fatalities would have been survivable at 40 mph.

At 80 mph, death is nearly certain. The Camry has a whopping 928 KJ of energy, or 400% (4x) as much energy as it did at 40 mph, even though it’s “only” going twice as quickly. It has 178% of the energy it did when traveling at 60 mph, or nearly 2x as much, even though it’s “only” 20 mph faster.

Remember–crash tests are conducted at 40 mph for head on collisions, and there are a great many fatalities at 60 mph. At 80 mph, you or your loved ones have virtually no chance of survival in a crash, because the human body is not designed to sustain 400% of the forces at which cars are designed to make survivable (those at 40 mph collisions). The math doesn’t work.

How do we make people follow speed limits?

This is an excellent question. Basically, we have to enforce them, whether through police patrols or speed cameras. As long as it’s permissible from state to state to exceed speed limits by 5, 10, or even 20 mph, we’ll continue to see needless tragedies. As long as speeding is socially acceptable, people will speed in the belief that they are uncatchable, invincible, and perfectly in control of their safety and their vehicles.

They aren’t. Driving the speed limit–or below it–is one of the most effective steps you can take to increase your safety and the safety of your loved ones every single time you drive.

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If you find the information on car safety, recommended car seats, and car seat reviews on this car seat blog helpful, you can shop through this Amazon link for any purchases, car seat-related or not. Canadians can shop through this link for Canadian purchases.

Every winter, one of the questions I get from everyone is whether or not winter tires (also known as snow tires) are worth it. And every winter, I give the same answer: yes! I figured it was time to write an article explaining exactly why they’re worth it, and why you’d do well to pick them up before winter strikes again.

Why buy winter tires?

To put it simply, there are at least 5 reasons why winter tires are worth buying:

1. It’s not just the snow; it’s the temperature!

This is likely the single biggest mistake people make when justifying a bad decision to skip winter tires. Maybe you live in a part of the country where you don’t get snow every day, or where the snow you do get is just a few inches here or there that the plows typically clear out by afternoon. Or maybe you do get a lot of snow some winters, but this winter they’re predicting a light winter with not much snow, or you’ve just been lucky so far and are trying to save a few bucks.

All of these rationalizations are just that: rationalizations. Because you know what? All-season tires (commonly called no-season tires by safety afficionados) don’t just do a poor job with snow, they also do a poor job whenever it gets cold. Below around 45 degrees Fahrenheit, regular tires start behaving like used gum or play-doh that’s been left in an open container: rock hard. They lose their stick and lose their grip, which means they do poorly in the winter regardless of whether the road itself is bone dry or covered in snow, slush, ice, rain, or anything else. This means longer stopping distances, less traction, less maneuverability–you name it.

Winter tires are designed to be used in cold weather; they’re made from rubber that works best in the very temperatures where regular tires let you down.

2. All wheel drive is not enough. Nor is front wheel drive.

Another commonly-raised defense is that used by SUV drivers around the country: I have 4-Wheel Drive! I have All Wheel Drive! Similarly, car drivers gallantly proclaim: I have Front Wheel Drive!

Unfortunately, none of these drives are enough. All wheel drive can help you maneuver out of certain situations when you’re stuck and need to start moving, but it doesn’t do anything to help you with stopping or steering, which are usually where people go wrong right before a collision, whether that collision involves another car, a semi, a tree, or a guard rail.

Once again: all wheel drive helps you start. It does not help you stop.

What this means is that while marketers may make car commercials showing your Jeep / Ford / whatever powering up the North Mountain in post-Elsa Arendelle, it has pretty much nothing to do with reality. Let me tell you something: around half of the SUVs or pickups I research about in winter driving deaths are AWD or 4WD models. And whenever I’ve been unfortunate enough to drive past scores of vehicles littering the ditches after an ice storm or really bad snow storm, they’re almost always the big, bad SUVs with the 4WD Off Road Domination insignia everywhere.

Front wheel drivers, you’re no better off, unfortunately, for the same reason: whatever you’re using to drive you isn’t what’s going to stop you. Every vehicle already has four wheel braking and two wheel steering; what matters is what’s touching the road.

3. Traction control, ABS, and stability control are useless.

When I say traction control, anti-lock braking systems, and electronic stability control are useless, I don’t really mean useless in the sense that you should drive your vehicle with these features into the nearest landfill. They’re all great features, especially ABS and ESC, which together will likely save as many lives as seat belts in the coming years now that they’re finally standard on vehicles. But much as how your seat belt won’t save you if you’re driving into the path of an oncoming semi (the forces are just too great), ABS and ESC won’t make a meaningful difference if they don’t have tires that help them do their job.

Yes, ABS will brake your vehicle as much as possible regardless of how bad your tires are, and ESC will take things a step further and selectively brake your wheels in effort to keep you from spinning like an ice skater into that frozen lake on your right as you slide screaming off the road, but in order for them to help save your life, they need tires that give every advantage possible in the treacherous conditions of winter driving. I’ll take a car without ABS or ESC but with winter tires out into an ice storm any day over the same car with ABS and ESC but with bad tires. That’s how much of a difference they make.

4. You can’t always stay off the roads or simply drive slowly.

This is a point I used to use myself back when I was a Winter Tire Denier, so I’ve got a lot of empathy when I see other people use it. The argument is that if you drive slowly and carefully enough, then you don’t need winter tires. Or to take it to an even greater extreme, if you can simply stay off the roads, you won’t have to worry about this at all.

Both of these are true to an extent, but the very fact that both points are used as arguments suggests that you know deep down that you are taking a significantly greater risk by foregoing winter tires. I knew that back then too; I just didn’t want to admit it, so I kept telling myself that as long as I drove carefully, things would be okay.

For me, they were. But that’s not the case for everyone. In fact, that’s not the case for about half of the people who die in the US every year due to car collisions. Half of all fatalities are single-vehicle fatalities, which means no other vehicles hit these drivers before they died. The fact of the matter is that there are a number of road conditions out there that are simply beyond the skill of any driver. That’s why we have technology help us as much as possible. Winter tires are some of the finest technology invented for winter driving.

Yes, staying home is safer. But it’s not always possible. Emergencies pop up every day around the country, whether in the form of medical situations, family situations, food situations, or simply unforeseen circumstances. And if you’ve got a vehicle, it means you acknowledge that there are times when you’ll need to drive. So why not buy a set of winter tires and rims so you’ll have a very basic, but very meaningful advantage each winter?

5. An ounce of prevention is worth a pound of cure, or the life you save may be your own.

Finally, and most frankly, I’m going to state the obvious: there are certain mistakes in life you can’t take back. I’m an optimist, and believe that most mistakes are generally manageable, although the consequences may take an exceptionally long time to manage. But some things are different, and the most obvious example is death.

If you or your loved ones get into a crash that would have been preventable if your vehicle had been outfitted with winter tires, you’re not always going to be fortunate enough to be able to do things over. And unfortunately, there are hundreds of these kinds of deaths each winter–deaths that are directly attributable to people losing control of their vehicles due to using tires that were simply unsuitable for the road conditions.

One example that comes to mind involves Deana May Igoe, whom I wrote about last year. You’ve probably never heard of her, but she was a lady traveling across the country who lost control on a highway in Oregon in early spring 2014, and skidded sideways into the path of an oncoming SUV. She died at the scene. This sad scenario repeats itself over and over each year with drivers who either don’t know or don’t care about the benefits of winter tires. Don’t let your family members join the statistics. You can buy good winter tires for your vehicle from just about anywhere. I bought mine from Amazon to take advantage of the free returns and shipping, but it doesn’t matter where you go. Just get them, and tell everyone you know to get them too. Life is short enough.

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If you find the information on car safety, recommended car seats, and car seat reviews on this car seat blog helpful, you can shop through this Amazon link for any purchases, car seat-related or not. Canadians can shop through this link for Canadian purchases.