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The Need, the Need For Speed = Safety!!!
Faster is Safer!
My Sister-in-Law just couldn't understand, why I felt that going faster, on a bicycle, is safer. "30 mph!" ... "You're gonna kill your self!". ...
I feel it necessary to prove that 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.
At 10 mph -
60min x 10cars - 1/3 (for 1/3 speed of cars) = 400 cars passing you at 20mph.
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!
At 30 mph -
20min x 10cars - 3/3 (for 3/3 speed of cars) = 0 cars passing you!
(Math is simplified - but "sound")
If you concede that most urban bike accidents are directly related to passing cars, then 20 mph would be (4 times safer than 10 mph) x (twice the time the, approaching, driver has to see biker) = 8 times as safe @ 20 mph, compared to 10 mph!
A__hole factor! Everyone might agree that, possibly, 1 in 100 motorists, (conservative estimate!), are AHs toward bicyclists, Going 10 mph you'll get passed by 4, only 1 @ 20 mph and at 30 mph you might never encounter 1.
My Sister-in-Law just couldn't understand, why I felt that going faster, on a bicycle, is safer. "30 mph!" ... "You're gonna kill your self!". ...
I feel it necessary to prove that 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.
At 10 mph -
60min x 10cars - 1/3 (for 1/3 speed of cars) = 400 cars passing you at 20mph.
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!
At 30 mph -
20min x 10cars - 3/3 (for 3/3 speed of cars) = 0 cars passing you!
(Math is simplified - but "sound")
If you concede that most urban bike accidents are directly related to passing cars, then 20 mph would be (4 times safer than 10 mph) x (twice the time the, approaching, driver has to see biker) = 8 times as safe @ 20 mph, compared to 10 mph!
A__hole factor! Everyone might agree that, possibly, 1 in 100 motorists, (conservative estimate!), are AHs toward bicyclists, Going 10 mph you'll get passed by 4, only 1 @ 20 mph and at 30 mph you might never encounter 1.
Total Comments 5
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Being hit ... or hitting something.All examples are based on 30 mph traffic speed and a comparison of 10 mph and 20 mph bicycle speeds.
Of course, faster speed will produce a more damaging impact! BUT!!! I am speaking of the danger from other vehicles. In a worse case of a direct rear collision, a 10mph, (bike speed 20 mph), impact might only slightly damage the bike and leave the rider seated and sensible, capable of recovering, or a controlled "crash", while a 20 mph, (bike speed 10 mph), impact would probably unseat, injure and render, the rider, dazed or senseless, fully at the mercy of the road, and traffic. At any speed, if hit from behind by a vehicle, you will almost instantly be accelerated to 30mph. At 20 mph the initial impact will be 1/2 the severity of the bike at 10 mph. Of course secondary impact might be the same, except, rider would be in much better physical, mental and mechanical condition to escape, or lessen, injury. On a lighter note, a swipe from a mirror, door handle, or even, fender at 10 mph, (bike speed 20 mph), might bruise but would probably leave the biker physically and mechanically in good condition, while a 20 mph, (bike speed 10 mph), swipe would very likely cause major physical and mechanical damage and very likely a nasty crash. Most any biker would prefer a 20 mph controllable "redirection" to a 10 mph uncontrollable "crash". |
 
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Speed Kills ... NOT!All calculations are based on:
1. a 30 mph speed limit 2. 10 mile trip 3. traffic density of 10 vehicles per minute passing a static point 4. bike speed of 10 mph vs 20 mph vs 30 mph There will always be the odd driver "Not Paying Attention" (NPA). 1 in 50? On a 10 mile trip: 1. at 10 mph, you will be passed by 400 vehicles, flying by at 20 mph. . NPA driver has 8 seconds to notice biker, = 8 NPAs .. NPA danger 800% greater than at 20 mph!!! 2. at 20 mph, you will be passed by 100 vehicles, coasting by at 10 mph. . NPA driver has 16 seconds to notice biker, 2 NPAs/2 (double time) = 1 NPAs .. NPA danger reduced by 87.5%!!! 3. at 30 mph, you will be passed by 0 vehicles, maybe 1 or 2 speeders. . NPA driver, not a factor, or number reduced to the infinitesimal! |
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Cocky SOB!My entire thesis on the "Math of Speed" is based on the assumption that I can handle anything that shows up in front of me. I religiously keep my bikes, and myself, in best possible condition & tuned up.
No! I do not rely solely on myself, being seen and communicating intentions to others is of great importance. My bikes are equipped with tail light, brake light, turn signals, Bright, or Strobe, headlight, with additional flashy red light on back of hat. Also in the development stage is a helmet with additional front Headlight-Strobe, to join, mounted rear flashy light and rear view mirror. My addiction to Speed is for the purpose of minimizing the one factor that I have no control over ... passing vehicles and their drivers. As shown by my math, in my typical travels, this hazard is reduced by almost 90% by increasing speed, from 10 mph, to 20 mph. For comparison purposes ... That translates to an "incident", every year, compared to, once in a decade! |
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Updated 03-17-2010 at 04:09 AM by DrkAngel |
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150lb Biker vs 3000lb Car?Any direct impact by a car will, (almost), instantly accelerate a biker to, (very near), the vehicle speed, regardless of biker speed, or direction.
Math based on rear impact, at various speeds C=Car B=Biker "Result" is the, post impact, resulting speed for car & biker both. 3000lb C (30mph) vs 150lb B (stationary) = 30mph impact = 28.5mph result Initial impact comparable to fall from roof of 3 story building, onto hard car Damage=probable broken bones, severe internal & head injuries etc. 3000lb C (30mph) vs 150lb B (10mph) = 20mph impact = 29mph result Initial impact comparable to fall from roof of 2 story building. Damage=possible breaks, internal injuries, concussion etc. 3000lb C (30mph) vs 150lb B (20mph) = 10mph impact = 29.5mph result Initial impact comparable to fall from roof of 1 story building. Damage=possible sprains, bruises etc. 3000lb car @30mph could be completely stopped by head on collision with 150lb biker @600mph, (near Mach1)! Sorry, ... got carried away by math, it can be fun, ... maybe not for that biker tho ...  |
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Updated 05-04-2010 at 05:22 AM by DrkAngel |
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Other Traffic! 10 mph Biker vs 20 mph - 30 mph TrafficQuote:
Originally Posted by BlazingPedals;
I'm not arguing for or against speed, but I should point out that your math only allows for hit-from-behind accidents. Only about 1 in 7 are of that type; most are right-hooks, left crosses, or cars coming out of a side street.
Biker at 10 mph vs 20 mph in a 30 mph traffic situation. Per mile - 10 mph biker will be: 1. passed by 4x (times) as many vehicles = a. 4x the possibility of hit, or swipe x (2x impact speed) b. 4x the possibility of "right cross" ** 2. 2x the volume of oncoming traffic = a. 2x the possibility of "left cross" ** b. 2x possibility of head on x (.8 impact speed) (30 + 10 mph vs 30 + 20 mph = 80% impact speed) 3. 2x the volume of cross traffic, sidestreets, driveways etc. = a. 2x the possibility of cross traffic collision ** Note: Actual percentages listed where available. Other impacts are highly variable due to possible angle and bike into vehicle or vehicle into bike. ** Speed, or severity, of impact will vary, from 50% to 100% (possibly higher). Best case is 50% impact speed of 10 mph biker into side of vehicle. Worst case would be, side impact of biker by car, 100% impact speed. Possibility of being "run over" might be 2x, for the 10 mph biker. (Momentum of 20 mph biker is much more likely to carry him past the car = much greater chance of not being under car!)*** (Same direction impact already established at 200% speed-severity.) *** 20 mph Biker possibility of impact is approx. 25% to 50% that of the 10 mph Biker. Additionally, 20 mph Biker is 2x as likely to strike the vehicle while the 10 mph Biker is 2x as likely to be struck by vehicle. (Applicable to all, except same direction & head-on!) Possibility of 10 mph Biker going under vehicle is MUCH greater! The final, measurable, variable might be, "time to see", (tts), the biker. (10 mph biker) While following traffic only has .5x the tts, oncoming traffic has 1.25x the tts, and the cross traffic has 2x the tts. However ... the additional factor of faster motion being more noticeable, especially in the peripheral vision area, should be added, but, I'm afraid, assigning percentages would be sheer speculation. (Peripheral vision is much more attuned to detecting motion, as well as light, especially flashing light. Another good reason for a "strobe" headlight, during the day.) Personally, I believe, faster still looks a whole lot better-safer. |
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Updated 05-06-2010 at 01:57 AM by DrkAngel |
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