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Despite the title, this article isn’t about bicycle crashes. It’s about all kinds of traffic crashes. Auto vs. auto, auto vs. bike, and auto vs. person.

Traffic crashes are deadly, destructive, and common. They claim lives and inflict serious injuries that change lives forever. Traffic crashes are the leading cause of death among children up to age 19.

We can prevent that. We can prevent traffic crashes and we can alleviate the most destructive kinds of traffic crashes.

Let me reiterate that. We can save 700 lives per year in Virginia. We can prevent thousands of serious, life-changing injuries every year.

How can we do that? Before I explain what my bicycle has to do with it, let’s first consider an important element of crashes: speed.

The faster a car is moving, the more severe the crash. That’s not just common sense. It’s backed up by physics and observational studies. A difference of just 5 or 10 miles per hour can be the difference between life and death, between a close call and a lifelong disability.

The link between speed and crash severity is particularly clear when considering the auto vs. person crash.

  • When a car traveling 20 mph strikes a person, 90% of the time that person will survive.
  • Increase the speed to 30 mph, and only half the time will the person survive.
  • When hit at 40 mph, 90% of the time the person will die.
source: BikePGH

source: BikePGH

In Roanoke, 500 of the 600 miles of City streets have a 25 mph speed limit—but the typical speed is 33 mph. Just 7 mph over the speed limit can be the difference between walking away from a crash and paralyzed for life. It is literally the difference between life and death.

So how do we get people to slow down? I often hear, “Roanoke drivers are terrible,” or “People here just drive too fast.” (Every place believes their drivers are the worst!) We talk about traffic speeds as the result of driver decisions.

But many factors influence those decisions. A speed limit sign is just the beginning. We can use many tools to slow traffic speeds, depending on context: speed bumps, show-your-speed radar, enforcement, outreach campaigns, to name a few. New York, and other cities, found that bike lanes reduced injuries and fatalities for all users—not just bicyclists (for more data, see New York City’s Vision Zero report). Focusing on bicycle safety had the side effect of traffic calming.

When we make streets safe for my bicycle, the streets are safer for everyone—bicycling, walking, and driving.

Thank you Roanoke for new bike lanes, narrowing travel lanes, and other traffic calming efforts so we can ALL be safer traveling on streets.  Keep up the good work and motorists, keep an eye out for my bicycle and slow down!


  • Bruce Newman says:

    The statistics above are based on the fact that a collision has occurred. But when the car is traveling slower, the chances that a crash will occur at all is reduced, because the driver and/or the person walking will have more time to avoid a collision. Therefore, the relationship between speed and death is much stronger than the chart implies.

  • Rachel Ruhlen says:

    You are absolutely right about that. I’ve thought about that, but I think that is usually omitted from these discussions for simplicity, at least I haven’t seen a handy infographic or chart that really gets at the crash reduction effect of lower speed. Thank you for sharing that comment!

  • Paul Bender says:

    Good points from both of you!

    I think it comes from a US assumption that collisions WILL occur.
    I read years back that the US Federal Rail Admin assumes this, and has much stricter train car construction standards than in Europe- resulting in heavier, slower trains that consume more energy, but will increase survive-ability, should a collision indeed occur.
    Europe, on the otherhand, takes an Avoidance approach, investing in the technologies (often still missing in US) to PREVENT collisions in the first place, but trading off with lighter, less heavy trainsets that can travel faster and use less energy.
    Like everything in life, trade-offs everywhere,
    We as planners and citizens must have good information and reasoning skills to help us make these decisions, individually and collectively. 🙂

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