The purpose of Bicycle Safety -The Math of Speed is to numerically illustrate the relationship of a cyclists speed vs the quantity and velocity of passing vehicles. Further, it proposes that it is safer for the cyclist to maintain a speed that is closer to the speed of the passing vehicles.
1. In any traffic environment, especially on the open road, cycling faster means that you are passed by fewer vehicles = less possibility of collision.
2. These fewer vehicles have much more time to notice and make adjustment for you = less probability of collision.
3. Due to the resultant reduction in relative velocity, any contact with you would be less severe = greatly reduced severity of injury or possibility of death.
Do not be misled into thinking this was supposed to be some type of 1 page Bible of bicycle safety!
Others have gone there, and seem to have suffered varying degrees of cognitive malfunction.
The Math of Speed! - Index
10mph vs 20mph - passed by 30mph traffic
In 60mph Traffic
Other traffic - Biker 10 mph vs 20 mph - 30 mph traffic
The Solomon Curve
Bicycle Accidents - Causes
150lb Biker vs 3000lb Car
Rear Impact Solution!
Faster is Safer!
My Sister-in-Law just can't understand, why I feel that going faster, on a bicycle, is safer. "30 mph!" ... "You're gonna kill your self!". ...
I feel it necessary to prove that, up to the speed of surrounding traffic, faster is safer. Let me try a mathematical approach.
First, let me qualify;
1. My riding is in an urban area and 95% of the streets-roads are 30 mph limit.
2. I ride on the right side of the road, going "with traffic", as is the legal method.
For ease of math - Let's figure a 10 mile trip, w/traffic @ 10 cars per minute.
30 mph traffic:
At 10 mph -
60min x 10cars - 1/3 (for 1/3 speed of cars) = 400 cars passing you at 20mph.
At 15 mph -
40min x 10cars - 1/2 (for 1/2 speed of cars) = 200 cars passing you at 15mph.
At 20 mph -
30min x 10cars - 2/3 (for 2/3 speed of cars) = 100 cars passing you at 10mph.
AND, cars have twice the time to notice, and avoid, you! (vs 10 mph).
At 25 mph -
24min x 10 cars -5/6 (for 5/6 speed of cars) = 40 cars passing you at 5mph.
At 30 mph -
20min x 10cars - 3/3 (for 3/3 speed of cars) = 0 cars passing you!
(Math is simplified - but "sound")
When you consider that many bike accidents are directly related to passing cars, especially in a "road" environment, then 20 mph would be (4 times safer than 10 mph) x (2 - twice the time the, approaching, driver has to see biker) = 8 times safer @ 20 mph, compared to 10 mph!
Most impressive is that each speed increase of 5 mph reduces the volume of passing traffic by 50%!
A__hole factor! Everyone might agree that, possibly, 1 in 100 motorists are AHs toward bicyclists, (Conservative Estimate!), Going 10 mph you'll get passed by 4, only 1 @ 20 mph and at 30 mph you might never encounter 1.