Wednesday, August 5, 2009

Slow down. My philosophy for life also applies to the road.

I have been requested to post something positive.
In light of that request, I am putting a positive spin on what I was going to write anyway.

While I am generally good at pointing out problems and at complaining, I don't generally offer much by way of solutions.
This time I have a very concrete solution, which is within easy reach of ordinary Americans, with no risk, no cost, and a negligible amount of inconvenience.
It is something you, the reader, can do.

But first, a short history lesson:
In October of 1973 a group of nations got sick of the US "foreign policy" of military intervention, and, knowing we had developed a lifestyle totally dependent on oil, they agreed not to sell us any.
This caused massive and immediate affects throughout the US economy. Buying fuel, at any price, meant waiting in long lines - on those days you were even allowed to buy gas at all (hmm, so maybe Soviet era lines for goods were not caused by the distribution system of communism, but by a plain lack of resources...)

The government took steps to encourage conservation, which (unlike sourcing new oil) could be done immediately, such as banning Christmas lights.

Another major step they took was to enact a national speed limit of 55mph.

The reason for this is that at higher speeds air resistance increases exponentially* relative to speed. Going twice as fast requires 4 times the energy. This is as true of modern vehicles as it was in 1973. All vehicles, small or large, gas or alternative fuel, use more energy at speeds above 60mph. In fact, going from 55 to 70mph typically uses between 20% and 25% more fuel to go the same distance.**

Next, a physics lesson:
Similar to the relationship between wind resistance and speed, momentum varies with the square of speed.
This means that if you are going twice as fast, it will take 4 times as much force to stop - and therefor 4 times the braking distance in an emergency.
It also means that if you do end up in a crash, at twice the speed you will have 4 times the impact. At 4 times the impact, crumple zones and airbags can't stop your organs from hitting your ribs hard enough to explode.

I realize (from the almost universal comment I get when I mention I have a motorcycle) that people actually believe they are safe when they are driving a car.
The number one cause of death of youth in the US in car crashes. It causes more deaths among young people than murder, suicide, cancer, and heart disease combined. It is the number one cause of death up until age 40, at which point it is still in the top 3.
We don't hear about it much in the news precisely because it is so common. There are roughly 16,500 accidents significant enough to be reported in the U.S. EVERY DAY. Of these, roughly 1/3 result in permanent injuries. Every 12 minutes, an American dies in a car crash. Every time you get into a car, you may die.

The number one factor in causing all of these deaths and injuries? It isn't alcohol. It isn't teen drivers or cell phones. Its speeding. Speeding is the single largest factor in injury and fatality collisions. Contrary to popular belief, driving slower is safer even when other cars around you are speeding.****

Note a couple studies on the issue:
"risk of involvement in a casualty crash, relative to the risk for a car traveling at 60 km/h, increased at an exponential rate for free traveling speeds above 60 km/h [37mph]"**

“First, the probability of a crash is approximately proportional to the square of the travel speed. Second, in a crash, injury risk is approximately proportional to the impact forces on a person, which in turn are proportional to the square of the impact speed. These two effects can be summarized in a general rule of thumb: When travel speed increases by 1%, the injury crash rate increases by about 2%, the serious injury crash rate increases by about 3%, and the fatal crash rate increases by about 4% “**

There is, of course, an obvious drawback to driving slower: it takes more time to get somewhere. If you do the math, you discover that slowing down from 75mph to 65mph means it will take you an additional 7 seconds to go a mile. (Slowing down to 55 will cost another 10 seconds)

What all this means is, over a 10 mile commute, you will waste 25% more gas (which also means you spend 25% more money), and increase your risk of death by 160%, all to save 2 minutes.

I am not asking you to give up your car and rely solely on bicycles and public transportation.
I am not asking you to buy an experimental electric or alternative fuel car, an expensive new hybrid, or even a smaller more efficient car.
I am not suggesting you go to the lengths I do and remove your power steering pump and alternator, or drive 45mph on the freeway.

All I am asking is that you slow down.

If you value your own money.
If you value the environment.
If you value national security and energy independence.
If you value the lives of those around you.
If you value your own life.

You don't even have to care about all of those things. Any one of them of them is reason enough.

Leave the house 2 minutes sooner, and slow down.

This will not, all by itself, save the world. But it will make a difference.

Thank you.

"No one can cut you off if you choose to slow down and let them in"

*Disclaimer for math and physics people: I know, technically the curve is parabolic, not exponential, but if I used that term no one would know what I was talking about

**You don't have to take my word for it:

***Mass mean the weight of the car. Velocity means speed

****The chance of a fender bender may be higher if you go slower than traffic around you, but the chance of a crash which causes injury or death is lower.


  1. if you're going superfast, air resistance goes down????? well why don't we just do THAT on the freeways???

  2. what????
    no. Air resistance increases with velocity.
    But it isn't a linear relationship.
    If you go 1% faster, air resistance increases 2%.
    If you go twice as fast, the resistance increases 4-fold.
    At freeway speeds the air resistance is the largest external force that the engine has to overcome.