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 Advocacy & Safety Cyclists should expect and demand safe accommodation on every public road, just as do all other users. Discuss your bicycle advocacy and safety concerns here.

07-15-13, 03:22 AM   #26
DrkAngel
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Better than a horn! Gets you respect ... on sooo many levels!

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Last edited by DrkAngel; 07-15-13 at 03:37 AM.

 07-15-13, 11:54 AM #27 DrkAngel Senior Member Thread Starter     Join Date: Oct 2012 Location: Upstate NY Bikes: Various "modded" eZips and multiple econversions Posts: 336 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) 150lb Cyclist 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 ...
 07-15-13, 05:20 PM #28 OYO Junior Member   Join Date: Jun 2013 Bikes: Posts: 8 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) You are probably safer the faster you ride this ... https://www.youtube.com/watch?v=z6W7...e_gdata_player Last edited by OYO; 07-15-13 at 05:26 PM.
07-16-13, 07:17 AM   #29
DrkAngel
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I just re-found a representation of collision rate vs speed differential.

Collision rate would appear to be 20-25% for the 20m/imgh cyclist vs the 10mph cyclist, in a 30mph traffic environment.
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 07-16-13, 01:49 PM #30 turbo1889 Transportation Cyclist     Join Date: Aug 2011 Location: Montana U.S.A. Bikes: Too many to list, some I built myself including the frame. I "do" ~ Human-Only-Pedal-Powered-Cycles, Human-Electric-Hybrid-Cycles, Human-IC-Hybrid-Cycles, and one Human-IC-Electric-3way-Hybrid-Cycle Posts: 1,206 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 10 Post(s) Is that bicycle specific or is it just a general rule from car-car collision data? What are they defining "average speed" as being (do they mean average speed of cars on the road or the average speed of pedal bicycle)? What was their source data for the curve?
 07-16-13, 02:57 PM #31 wphamilton Senior Member     Join Date: Apr 2011 Location: Alpharetta, GA Bikes: Nashbar Road Posts: 12,231 Mentioned: 24 Post(s) Tagged: 0 Thread(s) Quoted: 1345 Post(s) I googled "Solomon Curve" and it's evidently research from the 60's graphing the number of car-car collisions against the car's speed difference from the average car speed on the road. I think it confirms OP's intuition about the diminishing likelihood of collisions as you get closer to the motor vehicle speeds.
07-21-13, 09:16 PM   #32
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Quote:
 Originally Posted by turbo1889 Since we have gotten into the humor end of the discussion, I'll join into that as well: If OYO is correct that in order for other drivers to respect you on the road you must represent sufficient threat to them ~ I believe that should do the trick. I was looking for a picture of a tadpole tandem I saw years ago on the net with hard mounted double forward gatling guns and the stoker sitting backwards with a single gatling gun on pivot mount for a tail gun but was unable to find that picture and those were the best I was able to come up with on short notice.
well if you really really need to be safe...

 07-22-13, 04:33 AM #33 skye Senior Member     Join Date: Mar 2010 Bikes: Posts: 888 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 19 Post(s) OP is making a common but utterly erroneous assumption. Most crashes do not occur as the result of unsafe overtakes; most collisions occur because of motorist inattentiveness (or cyclist error) at intersections, where the protective reduced speed differential favored by the OP can actually become an increased speed differential with deleterious consequences. In any event, physics is the wrong discipline with which to solve automobile-bicycle safety problems, which are essentially social and psychological in nature.
07-22-13, 03:40 PM   #34
DrkAngel
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Quote:
 Originally Posted by skye In any event, physics is the wrong discipline with which to solve automobile-bicycle safety problems, which are essentially social and psychological in nature.
Well ... personally ... my mind is constantly evaluating velocities and vectors of all moving objects in sight.
As well as combining this with variance potential and probabilities.

Physics Rules! ... Quite literally ... Everything!

Sorry, while I might socialize, to some extent, with cars, I just can't psychoanalyze all the vehicles coming at me.

Also ... don't see how that could possibly help?

Last edited by DrkAngel; 07-25-13 at 12:12 AM.

 07-22-13, 10:35 PM #36 turbo1889 Transportation Cyclist     Join Date: Aug 2011 Location: Montana U.S.A. Bikes: Too many to list, some I built myself including the frame. I "do" ~ Human-Only-Pedal-Powered-Cycles, Human-Electric-Hybrid-Cycles, Human-IC-Hybrid-Cycles, and one Human-IC-Electric-3way-Hybrid-Cycle Posts: 1,206 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 10 Post(s) @ DoubleDiamonDog As to separate cycle lanes not being needed and/or cyclist riding to the right of the main flow of traffic. I would be one of the ones that argues that it depends on the speed of the main flow of traffic (assumably the heavy vehicle traffic, it will be the "main flow" for quite a while longer I'm afraid). On roads with a speed limit of 25-mph or less and/or the main traffic flow is moving at that speed I find separate cycle lanes and/or riding to the right of the main flow of traffic to be not only unnecessary but more dangerous for the cyclist then riding in the main flow of traffic "taking the lane". On the other hand on roads where the speed limit is 45-mph or more and/or the main traffic flow is moving that fast if there is a safe, sane, and effective place to ride that is to the right of the main traffic flow and out of their way I most certainly find it best to ride there and I would most definitely like it if there were an official cycle lane available (provided it was done in a half way sensible way, as in someone who actually bikes as transportation laid it out and decided how it was routed through the intersections). And I can most certainly assure you that at least when you are riding "All In" (my term for riding with the main flow of traffic in low speed areas just like I were a motorcycle) instead of riding "Out" (my term for riding to the right of the white line on the shoulder edge out of the main traffic flow and out of the main lane) maintaining sufficient speed to make a good effort to keep up with traffic not only keeps you safer as far as rear impact capability and not getting passed as often and not making people behind you impatient. But far more importantly it earns you a huge amount of respect with other road users - or at least that has been my experience. Yah, there are still some obnoxious selfish idiots you have to deal with, and a few that have a deep rooted hatred towards cyclist, and there are a few on the other end of the spectrum who actually understand the rules of the road and will treat you right regardless, but for a huge segment of other drivers around you keeping up with traffic and maintaining speeds that at least approach theirs makes the difference in whether they treat you as an equal road user or not. In stop and go in-town, square grid, traffic I can do that under pedal power breaking above 20-mph under pedal power alone and accelerating up to speed as quick or quicker then they do. I can't do that for an extended period but with the little rests I get when waiting for the lights to turn I can do it and it makes a huge difference. When riding "Out" on the right edge of a high speed roadway, then what DrkAngel has to say about not getting passed by as many vehicles while covering the same distance and those vehicles having more time to notice you before passing you does come into play. But as you say for the "Left-T Crossers" especially (the guys who turn left across your path when they don't have the room to do so safely) running at higher speed could be a hazard giving you less time to brake and avoid the collision and making for a harder hit if there is a collision.
 07-23-13, 01:33 PM #37 Allen Senior Member   Join Date: Sep 2005 Bikes: Posts: 4,758 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 0 Post(s) Moved from Electric bikes
07-23-13, 02:37 PM   #38
Chris516
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 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.
Don't forget 'lane position' in that methodology. On a regardless of the speed you may be traveling, if you are 'hugging the curb', you are not making yourself known, and traffic will still blow by you, like you are just a 'speed bump'.

07-23-13, 03:44 PM   #39
Keith99
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 Originally Posted by Chris516 Don't forget 'lane position' in that methodology. On a regardless of the speed you may be traveling, if you are 'hugging the curb', you are not making yourself known, and traffic will still blow by you, like you are just a 'speed bump'.
Good point.

Honestly my single biggest problem (still not huge) was potential right hooks. Generally NOT jerks, just people thinking they had time to pass before a turn and finding out too late they did not.

Going at a speed that others do not expect often results in them initially assuming you are going at the speed they do expect.

I also do not like riding an intersection at my max speed. I want to be able to either slow or accelerate significantly. Same as when driving.

 07-23-13, 04:26 PM #40 DoubleDiamonDog Senior Member   Join Date: Jun 2008 Bikes: Posts: 447 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 13 Post(s) @ turbo1889 The beauty of the system in Vancouver is how it improved matters for drivers and cyclists. In the crowded, high traffic West End, they have selected some key streets and eliminated curbside parking, placing planters between the vehicle lane and the cycle lane in the old parking strip adjacent the curb. At the corner, a right turn arrow allows the vehicles next to the bike lane to make a right, then a turn is not permitted and the cyclists and other traffic lanes go, so it prevents the conflict of the right turn. Left turn functions similarly after the straight and bikes lanes turn red. The result is that cyclists seek out these safe routes and use them to efficiently flow through the city, keeping them off of the other streets where cars do not encounter them. I thought that it worked extremely well. In other areas they have the typical situation you describe - a painted lane for cyclists adjacent to the traffic lane. These are parts of a system with a separate recreational path shared by bikes and pedestrian along the waterfront, all around the peninsula and various traffic calming devices and vehicular dead-ends that reduce traffic on some streets to make them more bike and pedestrian friendly.
07-23-13, 05:06 PM   #41
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Quote:
 Originally Posted by Keith99 Good point. Honestly my single biggest problem (still not huge) was potential right hooks. Generally NOT jerks, just people thinking they had time to pass before a turn and finding out too late they did not. Going at a speed that others do not expect often results in them initially assuming you are going at the speed they do expect. I also do not like riding an intersection at my max speed. I want to be able to either slow or accelerate significantly. Same as when driving.
Right-hooks, are one reason I 'take the lane'. So, I can see them coming and have enough time to react.

As for going at a speed they don't expect, I feel that is a two-fold problem. Even if a cyclist is going say 25-30mph on a 30mph road(or even a 40mph road), some motorists' don't like it regardless of the fact that, they are not being slowed up in traffic, anymore than a motorized vehicle might do the same thing.

Staying with the point of how many vehicles pass depending on the cyclist's speed.

Behaviorally, A motorized vehicle will not pass another motorized vehicle, with the same amount of hostility. That they have, when they pass a cyclist. Because they consider them 'equal', instead of 'less than'.

So the greater the speed and lane position of the cyclist, the greater chance of equality.

07-23-13, 08:03 PM   #42
JoeyBike
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 Originally Posted by DrkAngel Faster is Safer!
I could not agree more.

Here is an old post (2007) from a Blog of mine. Enjoy!

"When I hit the road at the end of the bike path I tried to become part of the traffic flow immediately. I enter St. Charles Avenue a few blocks west of Broadway and Audubon Park. I did whatever it took to limit the number of vehicles overtaking me from the rear. For the next four miles, all the way to Lee Circle, I could usually maintain speeds between 20 and 24 miles per hour even though the road surface is not perfect. If I could draft a line of traffic and catch a few green lights it was possible for me to hang at 25 mph for a couple of miles. Early in the morning when school was out, it was normal for me to make the entire run and be passed by five or less vehicles. Zero passing vehicles was a rare treat that really got my crest waving high in the air."

07-24-13, 09:55 AM   #43
DrkAngel
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 Originally Posted by Keith99 I also do not like riding an intersection at my max speed. I want to be able to either slow or accelerate significantly. Same as when driving.
Personally ... I can decelerate from 20mph to dead stop in about 1 car length ... (less than 2 seconds~).
Might take me 10 seconds and the length of several intersections to go from 10mph to 25mph.

So I would much rather maintain good speed and slow quickly ... than cycle slowly and rely on comparatively feeble and desperate acceleration!

 07-24-13, 01:05 PM #44 Booger1 Senior Member   Join Date: Sep 2007 Location: Gaseous Cloud around Uranus Bikes: Posts: 3,732 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 26 Post(s) If the cars are only doing 30MPH,you must be talking about getting hit in a parking lot... If you do get hit at any speed,chances are,the only math you need to know is how to add.....so you know how much the doctor bills are. Last edited by Booger1; 07-24-13 at 01:18 PM.
 07-24-13, 01:27 PM #45 degnaw Senior Member     Join Date: Mar 2008 Location: Bellevue, WA Bikes: Posts: 1,606 Mentioned: 0 Post(s) Tagged: 0 Thread(s) Quoted: 1 Post(s) I'll preface by saying that I always go as fast as I comfortably can, because I don't think the safety differences are significant. That said, I do believe slower (within reason - let's say 15mph) is safer than faster (20+): -Motorcycling is more dangerous than cycling -Drivers aren't expecting cyclists to go fast - thus, they're more likely to right hook, left hook, or pull out in front of faster cyclists because they wrongly assume they can make their maneuver in time. -Faster moving cyclists are harder to see, leading to more left hooks and pull-outs. -IF you get hit, with the exception of a rear-end collision, you're a lot better off at a lower speed.
07-24-13, 01:36 PM   #46
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 Originally Posted by DrkAngel Personally ... I can decelerate from 20mph to dead stop in about 1 car length ... (less than 2 seconds~). Might take me 10 seconds and the length of several intersections to go from 10mph to 25mph. So I would much rather maintain good speed and slow quickly ... than cycle slowly and rely on comparatively feeble and desperate acceleration!
Most TDF cyclists envy your ability to stop.

07-24-13, 01:54 PM   #47
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 Originally Posted by Keith99 Most TDF cyclists envy your ability to stop.
Mebbe those TdF riders should learn how to skid and/or buy some disc brakes. Just sayin'

http://www.exploratorium.edu/cycling/brakes2.html

07-24-13, 02:03 PM   #48
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 Originally Posted by DoubleDiamonDog @ turbo1889 The beauty of the system in Vancouver is how it improved matters for drivers...keeping them off of the other streets where cars do not encounter them.
I call this ugly.

07-24-13, 11:39 PM   #49
I-Like-To-Bike
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 Originally Posted by Keith99 I also do not like riding an intersection at my max speed. I want to be able to either slow or accelerate significantly. Same as when driving.
Quote:
 Originally Posted by DrkAngel Personally ... I can decelerate from 20mph to dead stop in about 1 car length ... (less than 2 seconds~). Might take me 10 seconds and the length of several intersections to go from 10mph to 25mph. So I would much rather maintain good speed and slow quickly ... than cycle slowly and rely on comparatively feeble and desperate acceleration!
See http://www.slate.com/blogs/the_slate...irst_ever.html

Relevant info from the speedy cyclist:
"Around 8 a.m. I was descending Divisadero Street southbound and about to cross Market Street. The light turned yellow as I was approaching the intersection, but I was already way too committed to stop. The light turned red as I was cruising through the middle of the intersection and then, almost instantly, the southern crosswalk on Market and Castro filled up with people coming from both directions. The intersection very long and the width of Castro Street at that point is very short, so, in a nutshell, blammo. ... It was commuter hour and it was crowded as all getup. I couldn't see a line through the crowd and I couldn't stop, so I laid it down and just plowed through the crowded crosswalk in the least-populated place I could find."

07-25-13, 12:08 AM   #50
DrkAngel
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 Originally Posted by spare_wheel Mebbe those TdF riders should learn how to skid and/or buy some disc brakes. Just sayin'
Actually ... skidding will increase stopping distance.
The most effective braking requires well trued wheels, (for rim brakes), adjusted brakes and a "feel" for the precise point before wheel lockup.
Yes, it does require practice!

I've tested to the point of a lifted rear wheel ...