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Impact force: scooter compared to Accord

  1. Feb 8, 2010 #1
    I recently received a speeding ticket for "allegedly" driving my scooter (Piaggio MP3 500) 72Mph on a stretch of road with a lower speed limit. I was traveling too fast and I deserve to pay a penalty; however, I am also hoping the judge will recognize that a speeding scooter is less potentially deadly than a speeding car. For this reason, I sought to calculate the potential impact force of my scooter (538 lbs) at 72Mph -- compared to the potential impact force of the 3204lbs Honda Accord (for example). I believe J= mv/t is the appropriate equation, where:
    J = impact force;
    m1 = mass of scooter = 538lbs
    m2 = mass of Accord = 3204lbs
    v = velocity of vehicles = 72Mph = 105.6 ft-sec
    A1 = contact area for scooter = W*H = 2.54ft*3.67ft = 9.32ft^2
    A2 = contact area for Accord = W*H = 6.06*2.17 = 13.15ft^2
    t1 = contact time of scooter = A1/v = 9.32/105.6 = 0.088
    t2 = contact time of Accord = A2/v = 13.15/105.6 = 0.1245

    For my Scooter, J = 538lbs*(105.6ft-sec/0.088) = 645600lbs/ft-sec
    For Accord, J = 3204lbs*(105.6ft-sec/0.1245) = 2717610lbs/ft-sec

    Claim1: 2717610/645600 = 4.2; ie: a direct collision with an Accord traveling at 72Mph generates approximately 4.2X the impact force of my scooter traveling at 72Mph

    Claim2: 645600/2717610 = 0.238; ie: the potential impact force of a direct collision with my scooter traveling at 72Mph is approximately 76% less than the potential impact force of an Accord traveling at 72Mph

    Would I be justified in making these claims?
    Thank you, Scooterman
  2. jcsd
  3. Feb 8, 2010 #2
    In principle, I agree with this, because I think that in the real world, a motorcyclist will less often inflict harm on others. If it happens, it is probably because a car reacts to you and causes subsequent destruction. But this is a "second order", i.e. much more unusual, effect.

    Instead of detailed calculations, how about refering to statistics? How many innocent bystandards are killed or seriously wounded as a consequence of a speeding motorcycle? I.e. what is the probability of killing an innocent person, per km of "motorcycle-speeding". I would expect a very low number. If so, the punishment is only there to protect the motorcyclist people from himself/herself.

    Actually, maybe it even turns out that the probability for am ordinary car driver, that does not speed, to kill an innocent is higher than the probability of a speeding motorcyclist to do the same!?

    This punishment for inflicting harm on yourself should obviously be lower than that for inflicting harm on others. So motorcyclists should have lower fines, according to this argument.

  4. Feb 8, 2010 #3
    Speeding tickets are given out either

    - to stop you from speeding

    - to make money.

    there's no connection with vehicle mass here.
  5. Feb 8, 2010 #4
    So, you're going to tell the judge you are guilty, and you are taking up his time because you're a smartass. That's probably not a good way to get a lower fine.

    It's not less deadly for the scooter operator. Hence the fine.

    Or how about this argument: a pedestrian is less likely to see the scooter coming, and therefore steps out into the road, right into the path of the speeding scooter. Now while the impact force may be your factor of four less, I am certain the 72 mph scooter will kill the pedestrian just as dead as if he'd been hit by the Accord. Hence the fine.
  6. Feb 8, 2010 #5
    I think there is a connection. The size of the fine is related to the amount of speeding on the roads (there would be more speeding if the punishment was lower). The amount of speeding is related to the amount of injuries, which is related to vehicle masses.

    Will a large truck get the same fine for speeing as a small car?

    At least a bicyclist will not get the same punishment for using the sidewalk illegaly, as a car driver will... Simply because the car is more dangerous to other people. I would expect also that the police usually dont fine cyclists breaking the lowest speed limits.

    I suspect however, that the courts will simply ignore everything of this sort. They want the law to be simple.

  7. Feb 8, 2010 #6
    Yeah, but I'll bravely take a guess that this doesn't happen often in real life. I can't remember having heard of this happening. I have no idea if statistics are available (I'll try to find it).

    EDIT: I found one source that indicates that I'm probably wrong:
    http://www.youclaim.co.uk/motorcycle accident/motorbike-injuries-suffered-by-pedestrians.htm

    It claims that motorcyclists cause around 3-4 times more pedestrian fatalities, per mile travelled (in the UK).

    So I think I'll change my mind regarding smaller fines for motorcyclists.

    Last edited: Feb 8, 2010
  8. Feb 8, 2010 #7
    Btw, there was actually a case, I think in Germany, where a professional race car driver got a reduced punishment because he was considered by the court to be a better driver... :-)

  9. Feb 8, 2010 #8
    gmax: good point about the smart *** risk, but instead of an Accord, what if we were comparing a Tractor Trailer going 72 in a 45? Do you really think the driver of the semi should be punished the same as a guy going 72 on a scooter? A Semi at 72mph could to take out an entire school bus full of kids. There is flexibility in the law to account for "mitigating" and "compounding" factors. The potential risk that you pose to your fellow citizens is a big one. Furthermore, the law is more concerned with the risk you pose to your fellow citizens than it is with your personal preservation -- eg: nothing in the law will prevent you from drinking yourself into a coma right now.

    Torquil: Good comments - thanks for taking an interest; however, I don't think motorcycle statistics can be applied to scooters -- totally different mentality. There are a lot of macho adrenaline junkies out there on the Harleys and crotch-rockets getting drunk and going way too fast; the scooter community is much more reserved. Also (i neglected to mention), I am a long-haul commuter through the country-side, and I have never seen a pedestrian on the roads I travel. Never. Much different than in the city. If I were to hit anything, it would be a big-*** pick-up truck.
  10. Feb 9, 2010 #9
    Well I have had Harleys and other bikes, and I have had Vespas and Kymcos, and in my mind 72 mph on a scooter qualifies as 'way too fast' :eek:

    Please check back after your court date & let us know how it went.
  11. Feb 9, 2010 #10
    While you may be less likely to harm others you are more likely to harm yourself. Most states have laws that require seat belts (in cars) and helmets (on motorcycles). While I don't agree with those laws the point is that the government has established that they have no problem fining people for things that have virtually no chance of causing harm to others.
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