> eg if you are travelling at 30 mph and can JUST stop, if the > car next to you is doing 40 mph, what speed will they hit > the truck / obstacle / pedestrian at? > > Vimpact = (40^2-30^2)^0.5 = 26 mph > !!!!!!!!!!!!!!!!!!! I guess it also depends on many things as well, overall weight of the vehicle, type of brakes, tyres etc. I am always looking at the drivers maintaining high speed with small cars as they have less protection but the matter of fact they can stop earlier than me with my full "armoured" one. Also my ABS acts as driving on an ice in emergency situations, and I do not like that at all as I won't be able to stop one day. I will do 30mph, the other 40 but it will be actually me who will hit that child. With the site: Looks good and is useful I think. What I was thinking of is that I could not find info on maintaining steady speed over stop n' go impacting the fuel consumption which I thing would be interesting to see as well. Also could be nice to see some studies on relaxed or stress less driving from a psychiatrist / psychologist. Tamas On Tue, Apr 15, 2008 at 3:26 PM, Apptech wrote: > > So my wife and I are launching a new website regarding the > > benefits of > > driving more slowly, and I'm hoping that you have a little > > bit of time > > to check it out and give me your thoughts, comments, and > > critiques: > > > > http://www.driveslowly.org > > The following may be of interest: > > McMahon empirical formula for pedestrian-car fatalities > (reasonably accurate) > > Pedestrian death rate on impact ~~= V^2/25 % > > V in mph > > eg 30 mph -> 900/25 = 36% > 40 mph -> 1600/25 = 64% > 50 mph -> 2500/25 = 100% > > Above 50% you die more than once :-) > Statistical mean. Some are lucky and some aren't. > But the 30 mph to 40 mph change is enlightening. > _____________________________ > > McMahon empirical stopping formula. > Assumption - brakes remove energy at constant rate. > Zero reaction time. > Works well enough to be impressive. > > If you can JUST stop in time at Velocity1 then, if you are > travelling faster at Velocity2 your impact speed will be. > > Vimpact = sqrt (V2^2 - V1^2) > > eg if you are travelling at 30 mph and can JUST stop, if the > car next to you is doing 40 mph, what speed will they hit > the truck / obstacle / pedestrian at? > > Vimpact = (40^2-30^2)^0.5 = 26 mph > !!!!!!!!!!!!!!!!!!! > > Hard to believe, but close enough to correct. > > Both the above are related to the fact that vehicle energy > rises as V^2 but that brakes tend to work at about constant > energy. > > Adding reaction times makes the impact velocity figure > worse. > Adding brake fade etc makes it worse as well. > > In the stopping example above, if the obstacle is a child > chasing a ball, if the 30 mph car just stops in time, the 40 > mph car will kill the child about > > 26^2/25 =~~ 25% of the time. > > > > Russell McMahon > > > > > ----- Original Message ----- > From: "M. Adam Davis" > To: "Microcontroller discussion list - Public." > > Sent: Wednesday, April 16, 2008 1:25 AM > Subject: [OT] Website Critique - request for help > > > > So my wife and I are launching a new website regarding the > > benefits of > > driving more slowly, and I'm hoping that you have a little > > bit of time > > to check it out and give me your thoughts, comments, and > > critiques: > > > > http://www.driveslowly.org > > > > We're not expecting to make any money off it, but I was > > surprised at > > how much I save by going 5-10mph slower than usual, and I > > wanted to > > try out a new webhost and Drupal 5. If it pays for itself > > (under $200 > > per year) I'll consider it successful. But even if it > > doesn't I'll > > have vetted a hosting service, learned a bit more about > > Drupal > > development, and it'll have been worth it. > > > > So let me know what you think, and feel free to pick apart > > the numbers > > presented, or point out areas where I don't fully explain > > my > > reasoning. While it's primary audience won't be > > engineers, I do want > > it to pass reasonable scrutiny. > > > > Thanks in advance! > > > > -Adam > > > > -- > > Drive slowly - save money, gas, the environment, and > > lives. > > http://www.driveslowly.org > > -- > > http://www.piclist.com PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- Rudonix DoubleSaver Did You Know that DoubleSaver is Smaller and More Powerful FailSafe Device than Any Other You can Get? http://www.rudonix.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist