Strong Towns and speed limits

I am a strong supporter of Strong Towns, and think their analyses of financial and transportation issues is almost always spot on. However, I think there is a blind spot when it comes to speed limits. In a recent broadcast, Chuck Marohn addresses a question from a member about whether it is better to change speed limits street by street, or all at once. In response, Chuck launches into his view that only design changes can control speed. This is the first question in the broadcast, so you can listen from the beginning.

Here is my response:

I have to push back against Chuck’s take on speed limits. Nothing he says is incorrect, but there is an underlying ideology that rejects changing speed limits without changing design, as any part of a solution.

  1. This is not about enforcement. I agree that much of traffic enforcement is pretextual, and intended to oppress people of color and low income. I’m not asking for any more enforcement, and am in complete agreement with the current movement towards removing most traffic enforcement from the responsibilities of armed law enforcement agents. And moving speed and red light running enforcement to automated systems. In high risk, high fatality/injury settings, we could even invest in automated enforcement of failure to yield to people in crosswalks, which is a driver behavior that not only kills people walking but intimidates them out of walking.
  2. Chuck correctly states that drivers respond to roadway design, and consider what feels safe in setting their own speed. However, he misses the fact that drivers also respond to the speed limit. Drivers are very aware of posted speed limits. I constantly hear drivers say things like “I always go 5 mph (or 10 mph, or…) over the speed limit”. If the speed limit is 25, they will go 30, or 35, not just based on roadway design, but on the posted speed limit. If we lower it to 20, they will go 25 or 30. That is a huge difference (see the fatality at various speeds charts), and should not be discounted.
  3. The problem with 85% is not just that it allows drivers to set their own speed limits, but speed creep. If 85% indicates a ‘safe’ speed of 35, and it is posted, then drivers will start going 40, and the next survey will show 40 is the ‘safe’ speed, and so on, ad infinitum. Regardless of the impact on drivers, every increase in actual speeds makes the street less safe for people outside vehicles. Which is why high speeds should be reserved for limited access, designed for higher speeds, roadways. Streets should always be posted for the desired safe speed, no matter the roadway design.
  4. I live in a city where, at the current rate of roadway redesign, it will take about 80 years to create a safe system, and in a county where it will take at least 120 years. I am not willing to accept the death and severe injury that will happen in the meanwhile. We must do anything and everything we can to reduce that trauma, and that includes lowering posted speed limits.
  5. There is evidence from around the world that when speed limits in a city are lowered wholesale, both the rate and severity of crashes also decreases. By as much as we want? No, but to reject this change out of hand for ideological reasons is, in my mind, a huge mistake.
  6. There will always be egregious violators, drivers who drive as fast as they can no matter what. I think these drivers are actually responsible for most crashes. If these drivers can be caught and punished (removal of driving privilege and confiscation of vehicle) by any sort of enforcement, that is great. Redesigning a roadway does not eliminate these drivers or reduce their speed, it just makes it more likely that they will kill themselves along with the other people they are killing. That is small consolation.

I am absolutely in favor of roadways designed to self-enforce lower speeds. I have supported and helped design projects to do exactly that. And at no time have I ever felt that was enough. I think we need to use every action at our disposal (except biased traffic enforcement) to lower speeds. Now, not at some time in the future.

prudent drivers as traffic calming

Now, on to why I brought up the topic of prudent drivers. A prudent driver on a two lane (one lane in each direction) roadway largely controls the behavior of irresponsible drivers. On wider roads, with two lanes or more in a direction, whether a one-way or two-way, the irresponsible driver can do as they wish, violating laws and endangering others. On the narrower roadway, the irresponsible drivers get irritated, and honk and cuss, but there isn’t much they can do about it. This difference in large part explains why fatality and severe injury crashes are rare on residential streets within neighborhoods, and are common on arterial streets with multiple lanes. It also explains why rural roads have such high crash rates, because the prudent driver there can’t really control other drivers. On two lane streets, prudent drivers set the tone; on multiple lane streets, irresponsible drivers set the tone.

We have proven, over the history of motor vehicle use in the US, that is is not possible to significantly change the behavior of drivers. Education doesn’t do it, enforcement (even when that used to be more common) doesn’t do it. Nearly all of the improvement in roadway deaths has been due to safer cars, not to safer drivers or safer roads, and now that improvement is reversing itself as more and more walkers and bicyclists are killed by irresponsible drivers.

I am not against education, if it is directed at the most dangerous behaviors, which it is not, and I am not against enforcement, if it is done in an unbiased manner, which it is not. Each state has an agency, usually called the Office of Traffic Safety (OTS), whose mission is to obscure the real causes of crashes and to blame walkers and bicyclist for their death and injury, and at the federal level, the National Highway Traffic Safety Administration (NHTSA) fulfills this function admirably. In this, they are often aided and abetted by the law enforcement agencies. The reason CHP is California is so opposed to automatic speed enforcement is because it would remove the mis-focus and bias that they otherwise rely upon.

Driver behavior must be controlled by roadway design. That is why I strongly believe that all multiple lane roads must be reduced. Two lane one-way streets must be converted to two-ways streets with only one lane in each direction (and any other lanes converted to pedestrian, bicyclist or transit use). Two-way roadways with two or more lanes in the same direction must be reallocated to other uses. Again, excess capacity would be converted to pedestrian, bicyclist, or transit use, or even to development as overly wide streets shrink to fit the real need.

I have no illusions about the huge change in traffic flow. Those drivers who have gotten used to having plenty of space for themselves (their cars) would have to figure out how to use less: fewer trips, shorter trips, slower trips. People would make different decisions about where they live, where they work, where they shop and recreate. As far as I am concerned, this is all to the good.

Our freeways are designed by the ‘best and brightest’ engineers to be as safe as possible, allowing errant vehicles extra space, protecting hard objects with guard rails and impact attenuators (crash barriers), and using ridiculously wide travel lanes, yet still have very high crash rates. Spending more money apparently doesn’t make freeways safer, and the explanation for this is risk compensation, the proven effect that irresponsible drivers will increase their unsafe behavior to maintain the same level of risk. Think about the daily news items about crashes that close freeways for significant periods of time, and how often they happen. None of these need to happen, and I’d argue that an irresponsible drivers is the primary cause of each and every one of them. This post is about local streets, not freeways, but it is worth remembering that irresponsible drivers are everywhere.

I don’t believe that one single death or severe injury for a walker or bicyclist is worth any amount of convenience for motor vehicle drivers. Not one.

So, I ask every transportation agency in the Sacramento region to:

  • cease widening roads, forever
  • analyze all one-way roads with three or more lanes to determine the most dangerous ones, and convert these within two years
  • analyze all two-way streets with more than one lane per direction for the most dangerous ones, and convert these within five years
  • analyze the remaining roads that are not one lane per direction, for the most dangerous ones, and convert these within ten years
  • complete conversion of all roads within twenty years
  • stop victim blaming