Originally Posted by

**DrkAngel**
**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.