Why Do We Have Speed Limits?

I haven't really done any research for this post. It's late, and tomorrow's Easter (Happy Easter everybody!). I just wanted to ask a question that was bugging me. Today I tried an experiment where I drove 15 miles an hour over the speed limit for half an hour. Not only did I never get stopped, I got passed by multiple people. If we can all drive 15 over the speed limit with impunity, what's the point of having a speed limit?

To further test this issue, I decided to drive exactly the speed limit on the way home. In an hour drive, I got passed by three police cars. If three police officers in a row decided going the legal speed limit was not required, why do we have a speed limit?

How does it make sense to have a law everyone agrees shouldn't be followed? And if everyone agrees it shouldn't be followed, how does anyone ever get a speeding ticket? How does a police officer justify breaking a law then giving a person a ticket for breaking the exact same law?

I am so confused. For my next experiment, I think I'm going to try driving the speed limit again. When a police officer tries to pass me, I'm going to accelerate to match his speed so he can't. I'm curious if he'll give me a ticket for going the same speed as him.


  1. You seem to be arguing against the presence of a speed limit by using an argument against a particular level of speed limit. Your argument also seems to reflect the idea that the level of the speed limit is designed with you in mind, but it's more likely that the level of the speed limit is designed based on a much worse driver in much worse road conditions: personal speed limits aren't practical, so the speed limit reflects lowest common denominator drivers.

    I'm aware of at least one study that did not find a statistically significant correlation between increased speed limits and motor vehicle fatalities, but I have also seen other studies that found that higher speed limits correlated with more and worse accidents; there's certainly a theoretical reason to expect more fatalities with a higher speed limit. Plus, based on what I have read, higher speed limits at the upper end cause lower fuel efficiency. Another consideration is that, for hilly terrain or windy roads, the speed limit should be limited by the visibility needed to stop a vehicle if something is on the road, such as a deer or a stopped vehicle.

    Of course, it's also possible that, in certain areas, the level of the speed limit is intentionally lower than necessary, to help the government raise funds from motorists.


    Regarding your next experiment, in at least some jurisdictions and some circumstances, it is illegal to accelerate when a vehicle is attempting to pass you.

    Happy Easter!

  2. I think we all consider speeding a victimless crime and most people have a hard time generating a lot of concern for something they find harmless and can't connect with a good reason. As a full-time bike commuter, I tend to think of cars and trucks as 2-4 ton weapons that, when wielded expertly and safely, can improve our lives a great deal, but when wielded carelessly, can cost lives needlessly. However, I'm much more hostile to fools with their noses buried in their phones (something I see every day) than someone who's speeding as I'd rather encounter a hundred speeders paying attention than one jackass watching Facebook while he's driving.

    I remember reading an article many, many years ago about the reason some vicitimless crimes must be enforced is that they can contribute to an overall sense of lawlessness and lead to an overall increase of more serious crime. I think the example used was someone's car up on blocks for an extended period of time. There may be a legitimate reason, but the area begins to look run down and criminals become emboldened. (As a homeowner, I know that is not exactly a victimless crime because he could be devaluing my home with his actions.)

    Speeding is similar in that the police can only allow it to go so far before they begin to crack down lest that area degrade into a free-for-all. Someone like you and me may push the limits by 10-15 MPH while other who are much more reckless will push them much, much further if left unchecked.

  3. L.J Zigerell, I'm not arguing against speed limits. I think speed limits are necessary and good. I would have no problem being required to follow every posted speed limit. My problem is I'm not even expected to follow the posted speed limits. I can drive 10 over the posted speed limits basically anywhere around here, and it's considered fine. In fact, some drivers will get mad at me if I don't. Think about that. There is a societal expectation for me to break the law!

    And it is completely arbitrary. If I go 10 over the speed limit here, I won't get pulled over. If I go 20 over, I might. If I go 30 over, I will. And if I go a couple counties over, those numbers will all change. I know of a couple spots where I will likely get pulled over if I go even 5 over the speed limit. How does that make sense? I'm allowed to break the law in some areas, but not others? I can break the law to some extent, but not to others? Police officers have total discretion in who they'll pull over for breaking these laws?

    I think speed limits are fine. I just think if we're going to have laws, they need to be enforced. Or if they're not going to be enforced, they should go consistently unenforced. If nothing else, I think they're should be some way for people to know what standards they're going to be legally held to. The idea a citizen isn't allowed to know what the legal system expects of them baffles me.

    You raise a good point about the experiment though. I should check the laws for my area. I'd still be willing to do it though. It'd be interesting to go to court and hear, "The driver broke the law by preventing me from passing him while I was breaking the law. But he broke two laws while I only broke one, so he should get a ticket." I'm sure that phrasing wouldn't be used, but it's basically the argument that'd have to be applied. I'd laugh at it. And heck, the worst that would happen if if the argument is upheld is a traffic ticket. That's hardly a big deal.

  4. Dell Wilson, that is a real argument which has been applied in a number of legal decisions. It is called the "broken windows theory." The idea is a single broken window doesn't mean much in and of itself, but people seeing it will take it as a sign broken windows are tolerated (a sign of weakness) so they will break more. That creates a cycle where things get worse and worse, all because ignoring little problems is taken as an invitation for larger problems. There are other factors as well, of course. For instance, if you tolerate small problems when they happen to others, those others will tolerate small problems when they happen to you.

    It's not just a matter of laws, either. The same theory has been applied to interactions within groups. For instance, mild bigotry may be tolerated by members of a group which largely doesn't approve of bigotry because it's viewed as a small problem. This can "signal" to people more serious forms of bigotry are tolerable. It's been suggested this sort of thing is what has led to increased bigotry in some areas, especially with intergenerational trends.

    I think the argument has some merit, but not in the way it's generally been applied. Law enforcement has used it to justify targeting things like "disorderly" behavior that isn't illegal, but is undesirable. The problem is undesirable behavior does not actually cause crime. It's a proxy for a deeper problem (lack of societal cohesion or something like that). Targeting the proxy rather than the actual problem means the actual problem will often go unaddressed. This can actually make matters worse when a simpler rationale would make things better:

    1) Good things should be done because they are good.
    2) Bad things should not be done because they are bad.
    3) Laws should be enforced because they are laws.

    If those simple guidelines were used to shape policies, things would get better. They're not because people always find excuses to make things more complicated. Then they come up with complicated justifications for policies which address a symptom of/proxy for a problem rather than the actual problem. I suspect it all comes down to people wanting to be able not to follow those guidelines when it suits them. When phrased that way, it's easy to see why it'd seem like a pretty screwed up system.

  5. Russ R., I've had similar advice given to me many times before. I've never been able to follow it. Whether it's a teacher or police officer, I respect them only insofar as they do what they're supposed to do. It may be unwise from a practical standpoint (goodness knows its caused me trouble in the past), but I'm not going to ignore it when someone does something wrong.

    For instance, I've had cops tell me I was breaking the law when I wasn't. My response was to be polite and inform them they were wrong. The result was I got stopped multiple times, and eventually I got a ticket for it. I could have avoided the hassle by doing what they wanted me to do, but it would have meant sacrificing some freedom because people were abusing the law. I can't bring myself to do that. I know it may result in me suffering consequences, but I'm not going to give up my freedoms because other people do wrong things.

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  7. It does seem 5 MPH is "safe" in most areas, but it definitely depends on the area. One area not too far from me has a reputation for strict traffic law enforcement. As in, people (supposedly) get pulled over for going 37 when the speed limit is 35. At the same time, there are a lot of 55 roads around here where people go 70 on a regular basis, and nobody gets pulled over.

    Think about that one. Where I live, you can go 2 MPH over the speed limit for an hour, get passed by multiple law enforcement officers who are speeding by more, then get pulled over for going too fast. I think that's insane.

  8. The speed limit laws were mostly reduced to 55 in response to the oil 'shortage' in the 70s, and then stayed in place as a safety measure. In the 90s they repealed the rule that states must have 55 MPH limits. It is a revenue source for so many places. If police are not pulling you over, that is a good thing, as the posted speed limit should be part of an overall judgment about your driving.

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