Bill Could Make it Easier for Cities to Lower Speed Limits

Image from Road Safety Facts from WHO
Image from Road Safety Facts from WHO

Research consistently shows that speeding vehicles greatly increase safety risks, for people in cars as well as for pedestrians around them. The faster a vehicle goes, the longer it takes to come to a stop. Faster speeds lead to higher likelihood of a crash, and the higher the speed of a crash, the higher the likelihood of serious injuries and fatalities. The chart above, from a World Health Organization report on traffic injury prevention, shows the relationship between speed and risk to pedestrians.

But cities in California have been hamstrung when it comes to lowering speed limits.

State authorities, to prevent local jurisdictions from creating speed traps—where speed limits are abruptly lowered so that local police can charge drivers for speeding and thus make money for a municipality—have severely restricted the way speed limits can be set in California. That has led to some unexpected and negative consequences for safety.

If a town wants to lower a speed limit, for example as part of an effort to make their downtown safer, it must conduct a speed survey of vehicles currently driving on the road. Then, says the law, it must set the speed to match however fast 85 percent of the drivers go. There is no accounting for either design or safety, except for one point: if an engineering survey were to show a need for a lower speed limit than that 85 percent rule would call for, then the results could be rounded downward.

One result of the kind of thinking this rule produces is that engineers have a hard time understanding that designing for slower speeds is a thing—that, for example, narrowing lanes or adding bulbouts could lead to safer outcomes for all road users.

And it has led municipalities to avoid even trying to lower speed limits. If most people are speeding in an area, the results of the required speed survey may force them to raise the speed limit instead. Nevertheless, cities are required to regularly update their speed limits, and must do so if they wish to enforce the limits. Combined with engineers’ tendencies to overdesign streets for “safety,” with wide lanes and clear sight-lines, California has witnessed a steady increase in speed limits over time.

This is pretty much the opposite outcome from what safe streets proponents would like to see.

Or course, speed limits, which after all are no more than numbers on signs, are not the complete solution to making streets safer. But they are one important tool, which cities are currently not able to deploy effectively.

That may change, if a bill by Assemblymember Laura Friedman (D-Glendale) is successful.

Glendale, says Friedman, has more than its share of pedestrian crashes and injuries, and the city has been dealing with the problems of street racing as well. Looking around for inspiration, she found L.A.’s Vision Zero efforts that create a framework for reducing casualties. Among its recommendations are to look at the actual crashes on a street or road or network and focus efforts on those areas that have the most serious problems.

Her bill would add only a few words to current law, creating another exception to the 85 percent rule. That is, under A.B. 2363, a local jurisdiction could use information from a collision survey to help it lower a speed limit. So if an area is found to have a high crash rate, an exception can be made.

Her staffers say Friedman is working with a number of organizations, including the city of L.A., the L.A. County Bicycle Coalition, CalBike, California Walks, and the CHP, to come up with a definition or guidance on what such a collision survey would entail.

Rock Miller, an engineer who has been working to change 85 percentile rule for a number of years, says the bill would need further amendments for it to work. For one thing, there is no provision for lowering the speed limit farther than just rounding down from the 85th percentile results.

Miller says that opposition to loosening speed limit requirements has been intense. A time-limited pilot program could get more support, and could be studied for effectiveness as well, he said. He also thinks it worth considering for the legislature just to direct Caltrans or the CAMUTCD, which is currently tasked with writing speed limit rules, to figure it out themselves, as they have said they have no authority to make changes.

At least Assemblymember Friedman has started the conversation. Let’s hope it leads to slower speeds and safer streets.

82 thoughts on Bill Could Make it Easier for Cities to Lower Speed Limits

  1. I don’t think you understand how those “studies” you’re citing work. Every collision, whether the primary factor was a lane change or tailgating or something else, has speed as a factor, since it directly affects perception/reaction time and the amount of energy released. It’s also far easier to be proactive about people violating speed limits than it is anticipating someone who is about to fail to yield.

    Speed is right up there with (and intertwined with) roadway design in efforts to reduce traffic deaths, and rightly so. We should absolutely be enforcing other traffic laws that people using cars habitually disobey, but pretending like speed doesn’t merit attention betrays the “less understanding” that you seem to be saying those you disagree with have.

    Again, I encourage you to read fully the federal studies from the NHTSA and others that I suspect you’re referring to, then follow up with the literally hundreds of other studies that also contradict your argument.

  2. Speed is AN issue with safety, it is just not the most important. It is easy to measure, it is obvious, and those with less understanding of traffic safety use is as a stick. The most recent studies on what causes accidents put Speed at #7 to #10 depending on the study. Improper lane change, following too closely, not using turn indicators, failure to at stop light or sign, failure to yield, driving outside of traffic lanes; are ALL more likely to cause an accident. All hard to measure, but all important. Speed is a simplistic solution just not the only or best solution.

  3. Higher speed roads tend to have fewer crashes per mile because they are often limited access or rural freeways with fewer conflicting movements. Relatively low crash risk on those roads is less a function of higher speeds and more of design. That design doesn’t translate to urban streets with driveways and a variety of users. And we probably wouldn’t want to even if we could — high speed roads make up the majority of fatal crashes despite lower crash risk overall (again, not because of speed), so that’s hardly an argument that we should ignore speed as a factor on any road.

    And again, the NHTSA, NTSB, WHO, ITE, TTI, OECD, and literally every other transportation professional, governmental, and safety organization recognizes that speed is a critical factor in traffic safety. Why haven’t you figured that out? What possible motivation could you have for suggesting we ignore such an important issue?

  4. If the goal is to reduce accidents, we should do things that help reduce the number of accidents, and not go to the route of “just slow down”.
    Separate bike, pedestrians and cars instead of trying to have all move at the speed of the pedestrian.
    Engineer roads based on the number of people using them, and update as needed. If the foot, bike, auto or truck traffic double on a roadway, and it is not reconfigured to reflect that, it should be considered negligence. Way past time to hold Transportation departments (City, Regional, State and Federal) accountable for sitting on their hands. Let’s focus on the problem not the symptoms.

  5. Speed does not CAUSE accidents, in fact poor drivers cause accidents. Slower speeds make everyone suffer because we can not enforce laws against the 5% of bad drivers.
    I agree with what you say that is true (higher speed accidents are more fatal) but I must push back on the crazy talk. Higher speed roads have fewer accident per mile. Please look because you will not find studies, state or local, that disputes that fact.

  6. I suggest you read a few more studies. The NHTSA is a decent place to start since you seem to like federal studies. You are flat wrong about the role of speed in crashes to a degree that’s rather embarrassing. Speed variability is also a factor, but dismissing speed itself suggests a level of willful ignorance that isn’t worth engaging with. Do your homework.

  7. I’ll agree that higher speeds increase the Severity of crash, but no study I have ever seen says that they increase the likelihood of a crash.

    In fact the opposite. If a car is traveling at or below the average speed of a roadway they are MORE likely to be involved in an accident. That is the fatal flaw in the lower speed argument.
    Speed is not, according to studies, the cause of accidents.

  8. Most federal studies on speed’s contribution to crash risk rely on police reports, and whether the officer checked off speed as a primary cause. It’s a silly measure even if you trust the officer’s judgment at the time. The fact is that higher speeds increase the risk of a crash and increase the severity of crashes, a reality confirmed by numerous studies, including federal ones. Lower speeds does improve safety, and claiming otherwise requires ignoring dozens if not hundreds of studies (federal and otherwise), physics, and common sense,

  9. The concept that lower speed improves safety continues the false hope that lower speed safes lives. Dozens of Federal studies over the last 40 years have shown that speed is about #7,8 or 9 on the list of causes of accidents. Driving 30 MPH instead of 45 MPH just increases pollution, uses more gas, and does not improve the safety of the roadway. Let’s focus on things that do; Better turn lanes, better road engineering, enforcement of distracted driving, etc. This will improve safety.

  10. We also have actual reports on the millions of dollars collected by for-profit speed cameras. If anyone thinks that is not a MAJOR reason cities use them, they are seriously mistaken.
    James C. Walker, National Motorists Association

  11. Allowing anti-accountability fringe lobbyist groups guarantees equally misplaced priorities. Your insistence that safety should take a backseat to the desires of people who chose to drive is shameful.

  12. Luckily we have actual studies on the effectiveness of speed cameras, so we don’t have to rely on your impressions. Researchers you yourself have cited have stated unequivocally that they improve safety. If you think that saving seconds of travel time justifies injuries and deaths, as you’ve essentially stated multiple times, we just have a difference in values, but you need to stop lying.

  13. Far too many of the rackets put the loot in their general funds, and when some proposals come along to end the cameras, the politicians cry a river about how will we replace the loot. Allowing for-profit camera companies to play ANY part in traffic enforcement guarantees the true motive will be profits.
    James C. Walker, National Motorists Association

  14. We will see what you comment after I post what I have experienced in Portugal.

    And it is patently obvious that if you reduce the actual 85th percentile speed on a collector or arterial by (for example) 10 mph, then you DO slow traffic. The problem with speed cameras or officer-run speed traps is they still issue thousands or hundreds of thousands of tickets in a big city – absolute proof they don’t work very well, except of course for the politicians who get to spend the loot from the largely-ineffective rackets.

    James C. Walker, National Motorists Association

  15. Of course I support engineering improvements; I work for a transportation engineering consultancy. I’m just pragmatic — we know we can save lives now with enforcement of proper, context-sensitive speed limits, so I support enforcement too.

    The problem with engineering changes — and I say this as someone who sees how these decisions are made regularly — is that a) they cost money that often is not available, and b) rightly or wrongly, safety improvements are often assumed to slow car traffic throughput. Old-school traffic engineers whose education was deficient often grossly over-prioritize automobile “level of service” when making recommendations, and the (thankfully weakening) cars-at-any-cost crowd will fight any change that might add seconds to a commute, even if it means fewer deaths.

    If you were honest in your belief that traffic law enforcement is a “racket” and sincere in your stated concerns for safety, instead of trying to abolish proven safety measures like speed camera enforcement you’d lobby for legislation mandating that revenue extracted from scofflaw motorists go toward Complete Streets programs, NACTO-compliant engineering improvements, and other best practices directed at safety. Instead, you seem dedicated to removing all accountability for motorists and oppose a potential funding source for the engineering measures you claim to support.

  16. Of course I support engineering changes. I work at a transportation engineering consultancy. I’m just pragmatic — we know enforcement of context-sensitive speed limits saves lives, so I support enforcement.

    The problem with engineering streets for safety — and I say this as someone who sees how these decisions are made regularly — is a) that they cost money, and b) safety improvements are often seen, rightly or wrongly, as slowing traffic. So old-school traffic engineers whose education was deficient in anything but “level of service” often don’t even consider them, and retrograde groups like yours oppose them.

  17. And you continue to support for-profit speed enforcement rackets, INSTEAD of supporting correct engineering changes that would improve safety significantly more. The problem with the engineering changes approach is that greedy officials cannot profiteer from them. I will explain the Portuguese method later which works very well but with no chance to profiteer.
    James C. Walker, National Motorists Association

  18. I’ve heard your conspiracy theories enough times. Some of us are working to improve road safety. Enforcement of context-appropriate speed limits improves safety. That you continue to insist costly engineering is the only route to safer streets while lobbying against proven life-saving measures like speed cameras is shameful.

  19. ONLY engineering controls the speeds of most vehicles, and cities would rather control the speeds of a few and make a bonanza of predatory for-profit speed traps. It is an immoral racket that no one should tolerate. I am currently experiencing a very effective speed control in 25+ villages in Portugal where no money can be robbed from safe drivers, but the speeds remain as low as the villages want. I will write it up later.
    James C. Walker, National Motorists Association

  20. Engineering, sadly, is expensive. We can save lives by holding motorists accountable now.

  21. The NMA opposes anything that holds motorists accountable. Using the 85th percentile speed as the sole metric to establish speed limits is a clumsy and outdated approach opposed by transportation engineering professional groups, governmental safety groups, and common sense. You cars-at-any-cost extremists have no shame.

  22. …during a period where people where increasingly deterred from choosing to walk or bike, as we’ve rebuilt our environment to the point where doing so is often dangerous and unpleasant due to the proximity of reckless motorists. And I see you’re still using VMT to spin the death rate, despite having it pointed out repeatedly how misleading that is. You NMA extremists have no shame.

  23. (Sorry for the delay, the internet link died in the tiny village in northeastern Portugal where I was. Now I’m in a bigger town.)
    2) Put bike lanes on streets that are roughly parallel to the main collectors & arterials that carry the bulk of the commuting & shopping traffic. Consider wide sidewalks on some arterials & collectors with separate marked lanes for bikes and pedestrians – an engineering solution that is common in Europe. 3) Post the main collectors & arterials with realistic speed limits at or close to the 85th percentile limits. If a multilane collector or arterial has an actual 85th percentile speed of 45 mph and lower actual speeds are required, this MUST be achieved by re-engineering the roadway so that (for example) 85% of the drivers now feel safe and comfortable only at speeds up to about 35 mph. Be aware that limits set too low on the major commuting routes may significantly reduce congestion and possibly diversion of some traffic onto smaller parallel streets that were never designed to carry commuting traffic and this may cause safety issues and backlash from those residents. 4) Have all crosswalks uniformly marked and well lit wherever significant pedestrian traffic is present. If mid-block pedestrian crosswalks are used, they MUST be well lit and use a device like the rapid flashing beacons or a HAWK. 5) At high pedestrian intersections, used advance pedestrian walk signals so pedestrian traffic gets established before cars get the green. 6) Have well marked school zones with flashing lights for up to one hour before & after class (and at lunch hour if kids are allowed off the grounds). Lower than the default town speed limits or the posted limits on collectors & arterials are allowed ONLY during those limited hours.

    There are likely a dozen more issues, but these would be a good start – IF safety is the goal, and not for-profit enforcement.

    James C. Walker, National Motorists Association

  24. That is likely a realistic parse. If we want to reduce the fatality rate notably below 1.16/100 M VMT, and are realistic that any serious reduction in the total 3.2 T VMT is not likely, then engineering – not enforcement – will be the key. Try 1) post almost all rural freeways and highways at the 85th percentile so drivers can cover distances at safe speeds without the fear of predatory for-profit enforcement. (more shortly)
    James C. Walker, National Motorists Association

  25. To parse your statistic slightly differently– in a group of 5500 people who drive 15,000 miles a year, one of them will die or kill someone this year. That’s about the number of people (students, staff, and their respective household members) associated with a medium sized high school..

  26. Most cities enforce for profits, knowing they do NOT enforce enough that the under posted limits actually get compliance.
    James C. Walker, National Motorists Association

  27. Yes, cities aren’t concerned at all about the demonstrable safety benefit of lowered speed limits and even moderate enforcement, and it’s all a conspiracy to punish innocent “mostly safe” drivers (who endanger others when they break the law). I wonder if you really believe your own propaganda.

  28. Cities ARE focused on the financial concerns, that is what makes most enforcement systems into for-profit rackets. They enforce enough to make high profits, but not enough to reduce the speeds of most vehicles below the 50th or 30th or 10th percentile posted limits because then the enforcement becomes a huge cost item in the budget – rather than the lucrative profit item.
    James C. Walker, National Motorists Association

  29. So you think cities should be focused on financial concerns rather than the safety effects of enforcement? That seems an odd take.

  30. When NYC enforces enough to drop the costs below the multi-million dollars of profits per year, I will acknowledge the change. It is NOT likely to happen – the profit $$$$ are too great.
    James C. Walker, National Motorists Association

  31. You’ve made that claim before, but there have been numerous studies of cities that have saved lives by enforcing traffic laws. It’s quantifiable. You don’t have to enforce to 100% compliance for law enforcement to prevent collisions.

    I think it’ says a lot about your character that you refer to speed limits set to levels that are appropriate for the environment — levels that prevent people from dying — as “arbitrarily low.”

  32. Old ground, covered many times before.
    Cities will NOT enforce heavily enough that most drivers won’t drive above arbitrarily low posted limits because enforcement becomes a huge cost item in the budget with almost no ticket revenue – instead of a profit center. Cities enforce enough to make the public believe “we are doing something about the speeding problem” AND enough to create large profit centers.
    James C. Walker, National Motorists Association

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