Your point about reaction time is well taken but I disagree with your comparisons. I would say riding at 20 vs a walker at 3 is nothing like a 70mph car and a 10mph cyclist. One is painful the other is dead. The differences don't end there. At 70 your braking time is MUCH longer. Your brain also has a lot of other things to visually process because you are passing many more objects. And the closing rate for 70 v 20 is 88 feet/second, for 20 v 3 it's 25 feet/second.
In your other example, the closing rate for 35 v 10 is 37 feet/second, for 10 v. 3 it's 10 feet/second, closing almost 4 times faster not the same. But closing rates and other numbers are hard to wrap your head around, so I like your idea of comparing. I don't see an issue with bikes going 20 on the path if it's done safely, so I'll make this comparison: biking at 20 mph closing on a ped at 3 is the same closing rate as driving at 27 mph closing on a bike going 10. Certainly worth being careful, but not so dangerous we need to outlaw it. All that said, there is some safe limit, but I don't know what it is or how to establish it. Maybe I'll know after I get hit. Reminds me of a quip from Seinfeld: "Ever notice everyone driving faster than you is a maniac, and everyone driving slower than you is an idiot?" - Seinfeld -Doug ----- Original Message ----- From: Darryl Jordan To: Scott Ellington ; [email protected] Sent: Tuesday, February 02, 2010 10:37 AM Subject: Re: [Bikies] NYTimes: An Electric Boost for Bicyclists A point worth considering regarding speed is closing rate speed and braking rate while on the bike path. Whether or not it is fully human-powered or assisted, the closing rate of a bicycle traveling at 10 mph approaching from the rear on a pedestrian traveling at at 3 mph is the same rate as an automobile at 35 mph approaching a cyclist at 10 mph. It's a timing issue of when to brake, pass, or react irrationally. A cyclist traveling at 20 mph is going nearly seven times the speed of a pedestrian. It's kind of like an automobile going 70 mph coming up on a 10 mph cyclist. Irrespective of the effects of less mass moving at slower speeds, a collision is still painful if one can't adjust in time. The other issue is visibility. Even at "moderate" speeds if a path user can't see an imminent collision approaching to react in time there's going to be trouble. I ride a recumbent and the bridges on John Nolan obstruct forward visibility so I have to slow down in anticipation of seeing someone approaching. I almost got rear-ended by someone on a mountain bike because he was too impatient to cross the bridge behind me. Of course it my fault that he was tailgating. My two cents Darryl --- On Tue, 2/2/10, Scott Ellington <[email protected]> wrote: From: Scott Ellington <[email protected]> Subject: Re: [Bikies] NYTimes: An Electric Boost for Bicyclists To: "bikies" <[email protected]> Date: Tuesday, February 2, 2010, 10:10 AM The article didn't really make it clear that some of them are actually electric mopeds. I think they are legal here, licensed like mopeds, for street operation only. The "Electric Assisted Bicycles" are very different, in that the operator generally HAS to pedal, and top speed is about 20 mph. There are some federal regulations designating them as "Low Speed Electric Bicycles". I believe one of the requirements is that the power assist has to cut out above 20 mph. I don't believe they are covered by any state legislation in Wisconsin, so they now exist now exist in a state legal limbo. While I believe that the 30 mph electric mopeds should certainly be banned from bike paths, I don't have a problem with their use on streets. They're quieter and less polluting than gasoline mopeds, and may get a few cars off the roads. I wouldn't have a problem sharing bike paths with electric assisted bicycles long as their maximum assisted speed is reasonable. I think 20 mph is too high; 15 mph would be more reasonable, as that's much closer to the speed of most cyclists. The last thing we need on shared paths is more high-speed bikes, in addition to the inconsiderate racer-types we already have. However, even with a lower top speed, they might get some cars off the roads and increase support for bike routes. Scott Scott Ellington Madison, Wisconsin USA _______________________________________________ Bikies mailing list [email protected] http://lists.danenet.org/listinfo.cgi/bikies-danenet.org ------------------------------------------------------------------------------ _______________________________________________ Bikies mailing list [email protected] http://lists.danenet.org/listinfo.cgi/bikies-danenet.org
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