More of the same: The double-standard of road rules

November 30, 2013 at 11:43 am

In unsurprising news, only 5% of drivers on the Illinois Tollway are obeying the 55mph speed limit, according to studies from the Tollway (via the Tribune).


The average speed is 66 to 70 miles per hour on many parts. And so this report from the Tollway has brought out a buzz-phrase: artificially-low speed limit. We now find drivers rationalizing speeding (a k a breaking the law) by claiming the roads have an “artificially low speed limit.” The argument is used to potentially raise the Tollway speed limit to 70mph, except in the Chicago area.

It’s actually a real concept based on the 85th percentile, which is how many speed limits are set. Traffic engineers observe the speed limit and set it to the speed at which 15% of traffic is not exceeding. In essence, drivers are setting their own rules. The logic goes, most drivers are reasonable, don’t want to crash, and want to get to their destination as quickly as possible, so the speed at which they’re already traveling is probably what the law should be.

In theory, I have no problem if people are speeding on the tollway. I’m not out riding my bike or walking to the store on the tollway. In practice, we should all be at least a little worried about it, because faster drivers create more pollution, drive faster on local roads when they exit the highway, and traffic flows better at 55mph than 80mph (those last two are from Tom Vanderbilt’s Traffic, a book I highly recommend).

The real problem I have with raising the speed limit because “people want to drive faster” (paraphrasing) is because this argument is a double-standard.

Might it be safer to drive faster on the highway? Maybe. People cite the speed of other cars as a reason to “go with the flow.” If you’re the only one going 55 on a highway where everyone else is going 70, you might get hit by an inattentive speeding driver. Is that your fault? No. Everyone else should be following the posted speed limit, possibly with technology to enforce it.

“For your safety, enforcement is automated.” Image: IIHS.

In France, for example, speed cameras on highways cut fatalities by 10%. They didn’t raise the speed limits (in fact, electronic signs instruct drivers to drive 100 km/h “for the environment”).

But the argument stateside says the speed limit should be raised so that everyone is traveling the comfortable speed.

Put this argument in another context: Bicyclists sometimes skip a red light or use the leading pedestrian interval to get a head start on traffic and establish their place on the street. This is especially helpful when there is a right-turn immediately ahead of the light, as a bicyclist getting ahead may be more visible to drivers turning right, and less likely to be right-hooked (it may also be safer to just wait for all drivers to pass, but on busy streets this opportunity may never arrive). There are times when it’s OK to just slow down at a stop sign on a residential street instead of completely stop. But you don’t even have to search for a newspaper article telling all cyclists to obey all rules. They seem to be published daily. For your own safety, just obey all of the rules, says the author who admittedly “rides a bike,” or worse, “is just going to keep their bike in the basement.”

The Tribune takes no opportunity to tell its largely suburban (driving) reader base to slow down for everyone’s safety. They quote rationalizations for a higher speed limit. I understand it; most people drive, so it’s easy for them to sympathize with breaking the law in this case, and it’s a politician’s dream to come around election time and be “the guy that let me drive faster.”

You’ll never come across an article in the Tribune that calls out for laws like the Idaho Stop which permit bicyclists to treat stop signs as “yield” or to use the leading pedestrian interval. We aren’t going to find a study that convinces the legislature to create separate laws for bicyclists and drivers, owing to the fact that they’re fundamentally different types of transportation. If 85% of bicyclists are skipping the stop sign, should we look at how the road is designed?

I’m going to keep following most laws when I’m out on my bike, but I also know it’s OK if I slow down instead of stop at an intersection like Leland and Dover. On my ride home through those residential streets, I’m just stopping at an artificially-high number of stop signs.

Note: For an example of a road with a truly “artificially low speed limit,” which is likely set for safety, see this post.