Speed Kills: Addressing the Real Road Hazard

Cities throughout California have taken steps to regulate e-bikes based on the belief that increased e-bike use is leading to collisions and dangerous conditions. These efforts ignore the real road hazard: speeding motor vehicle drivers. 

Reducing speeds on city streets is the best way to protect people biking and walking, especially those most vulnerable. A Streetsblog article by Angie Schmidt shows that the chances of a pedestrian dying in a 20 mph crash are three times as high for a 70-year-old as for a 30-year-old. Children are particularly vulnerable as well because they’re shorter, less visible, and more likely to be struck on the upper body or head.

We accept thousands of fatalities (4,407 in California in 2022, around 25% of those vulnerable road users) and many more injuries and lives upended due to traffic violence as a fact of modern life. But we don’t have to. In this post, we examine the factors that contribute to the culture of speeding and what we can do to change it.

The tyranny of the 85th percentile rule

According to the Insurance Institute for Highway Safety (IIHS), 29% of traffic fatalities in 2021 were caused by speeding. As speeds increase, the energy of the impact goes up exponentially, radically increasing the risk of serious injury and death. For example, in the Streetsblog article referenced above, Schmidt shows that the fatality rate nearly triples if a vehicle hits a pedestrian at 30 mph rather than 20 mph. 

A survey of pedestrian fatality data found that the chance of a pedestrian being killed when hit by a car doubled from 5% to 10% when speed increased from 18 to 23 mph (30 to 37km/h). The authors recommended maximum speed limits of 18 to 25 mph (30 to 40 km/h) in pedestrian zones.

Yet these recommendations can be hard to implement, even when California communities want to. The state’s primary method for determining allowed speed limits is the 85th percentile speed. This requires an engineering study to determine speed distribution on a street, and the speed limit is pegged to the speed 85% of drivers are driving at or below. AB 43, passed in 2021, gives communities increased flexibility to round speed limits down rather than up, but it doesn’t do away with the 85th percentile rule altogether.

Until California communities can set speed limits based on safety rather than car driver behavior, we’re missing a critical tool to protect vulnerable road users.

Invisible pedestrians

One factor that has contributed to an uptick in pedestrian deaths over the past few years is changes in vehicle design. Newer SUVs and pickup trucks often have much higher front grills than earlier models. This creates a large blind spot in front of the vehicle, which particularly endangers children. 

A study of crashes involving SUVs found that children were killed disproportionately by SUVs. In addition, trucks with front grills that top out at around five feet off the ground are more likely to strike adults in the head and neck and more likely to drag a pedestrian under the vehicle rather than over the hood. 

NACTO has called on the federal government to change the way it rates the safety of new cars to include danger to people outside the vehicle as well as inside. But the current generation of killer trucks and SUVs is likely to be on the roads for many years to come.

The car as a weapon

The vast majority of drivers don’t wish to harm anyone. But there’s been a growing trend of people (usually men) using cars as weapons. One of the more recent incidents happened in Huntington Beach, where a teenager deliberately hit three people riding bikes, killing one of them. This violent spree happened a few days after the Huntington Beach City Council considered a proposal to regulate e-bike riders because “[E]-bikes have not only become a nuisance to drivers but those driving the e-bikes have become a danger to vehicles and a danger to themselves.”

While there has been a lot of discussion of the dangers of teen e-bike riders, teen car drivers pose a much graver risk to our communities. Efforts to regulate e-bikes will do little or nothing to improve safety. But other measures can.

One study of speed interventions found that outliers (people driving far above the speed limit) had an outsized impact on pedestrian injuries. That points to the role of infrastructure changes, which can physically prevent drivers from speeding.

Built for speed: Dangerous street design contributes to fatalities

One might ask: Why would the 85% speeds be higher than the posted speed limit on a roadway? And further, how can drivers feel comfortable going so fast? The answer to both is in the design of our roads. Many of our roadways were designed by traffic engineers to provide unobstructed throughput for as many vehicles as possible. Travel lanes are often set wide enough for heavy trucks even when few (or none) use the road, and curbs are sloped to allow vehicles to turn without much slowing. 

Historically, engineers have added vehicle lanes to decrease delay for drivers at peak commute time, creating wide roadways with capacity far exceeding what’s needed for most of the day, all in the name of free flow of automotive traffic. These additional lanes provide a “cushion” for car drivers that helps them feel comfortable driving faster, but they actually increase congestion and delay on the road over time. 

These design choices, allowed within the prevailing guidance documents for engineers, combine to create an environment where car drivers feel comfortable — and have no physical restraints to prevent — consistently driving far above the posted speed limit. 

Fortunately, there are design tools that create safer facilities for people using all modes. The National Association of City Transportation Officials (NACTO), for example, has multiple guides that provide evidence-based ways to increase safety for people biking and walking. The Federal Highway Administration (FHWA) provides a list of proven safety countermeasures, many of which are aimed at preventing serious injuries and fatalities for vulnerable road users. In addition, the prevailing street design regulation and guidance documents (such as the MUTCD, Highway Design Manual, and AASHTO “Green Book”) provide for the use of “engineering judgment” to design facilities that may diverge slightly from the standard (car-centric) treatment.

CalBike has fought hard to create an environment where communities have the option to build less lethal streets. We helped pass legislation to legalize protected bikeways and to spread the word about Class IV protected bikeways. Protected bikeways have been shown to reduce fatalities not just for people on bikes but for drivers and pedestrians as well.

We continue to work to change attitudes about infrastructure. We created a Quick-Build Guide with Alta Planning + Design to help communities rapidly add elements to protect people biking and walking. And we’re surveying the condition of state highways that double as local streets to see where Complete Streets upgrades are needed. 

Slow Streets toolbox

The good news is that we know how to make our streets safer. The bad news is, we aren’t always using those tools. Pandemic Slow Streets spawned a movement to make those changes permanent, and some California cities have kept car-free or car-light spaces, while more have plans to do so. 

Here are some other measures that can help us rein in speeding motor vehicles:

• AB 645 will allow six cities to pilot speed cameras, which have been proven to deter speeding and reduce injuries. It’s on the governor’s desk now.
• AB 251 will study a tax on heavier vehicles, which could create an incentive for car manufacturers to make smaller, safer cars and trucks. It’s also waiting for the governor’s signature.
• AB 413 prohibits parking within 20 feet of a crosswalk approach, which will improve visibility. This bill is also with the governor.
• The NACTO Urban Street Design Guide includes a number of mechanisms to reduce vehicle speeds, including pinch points, chicanes, and speed humps. Infrastructure changes are the slowest and most costly way to prevent speeding, but they are the most effective.
• The League of American Bicyclists is hosting a webinar, “Slow Roads Save Lives,” on September 21. You can register here.
• CalBike is collecting data on local streets controlled by Caltrans to find where Complete Streets elements are needed to enhance the safety of people biking and walking. Take our survey by October 10, 2023, and tell us about your experience on your local streets.