Bicycle vs. Scooter Crashes and Physics

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ericalm
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Bicycle vs. Scooter Crashes and Physics

Post by ericalm »

Preliminary disclaimer: This isn't a gear discussion. We can have that chat elsewhere. This is about science and the rationale behind some statements read in discussions concerning gear.
Second disclaimer: I'm no scientist, but know enough to know that I cut a lot of corners here to make my points. I could be totally wrong, but here I go.

I've read a few posts in which members mention that they're cyclists and that they don't wear any more gear on a scooter than they would for a bike ridden at the same speeds. A few things about this rationale don't sit right with me. For one, a Buddy 125 weighs 225lbs. (dry), has a hot engine and exhaust, and is an all around more dangerous thing to have fall on you in a crash. Second, the physics of that argument don't really make sense to me.

Back to high school for Newton's Second Law of Motion:
F=ma (Force = mass*acceleration)
The part that concerns this is that inertia is dependent on mass. It takes a lot more force to accelerate a scooter plus rider (more mass) than bicycle plus rider (less mass). Stopping these objects requires an equal force in the opposite direction. More mass, more force.

Collisions are much more complex, but the gist is that impact force and the transfer of energy are also based on mass and velocity. Velocity being equal, the object with greater mass will collide with more impact force.

So, a couple conclusions, assuming equal velocity and equal mass of the riders:
• If the bicycle and scooter smack into the side of a car, the impact from the scooter plus rider will be much more severe.
• In fact, any collision on the scooter will have greater force of impact at the same velocity than on the bicycle.
• If each object goes down on its side, the force halting its motion will come from friction with the surface. Scooter goes down, more friction required to stop it. You're going to slide farther or harder.


It seems to me that crashes at the same velocity would be much worse on the scooter!

Am I totally off-base here? Misunderstanding the physics involved? FWIW, I looked it all up before posting!

Anyone have any particular insight to what happens when you're thrown from or become separated from the bicycle or scooter in a collision or slide?
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Post by tunseeker1 »

The physics involved in a crash are dependent on only your body. A crash at 20 mph on skis, a bike, scooter or roller blades imparts the same force potential. The weight of the person times the speed is the force.The scooter can potentially take you to a higher rate of speed.

In a car, which has a lot more mass, you do not use the mass of the car to figure out the effect on the human body. This is why we have safety equipment in cars. Watch old videos about the secondary crash that happens inside of the car after a car comes to a complete stop in an accident situation.

This is the easy version of the physics question.

As for the energy required to stop a scooter vs a bike. I would have to look at it to be certain but it might be close at slow speeds, but in a panic stop you have a greater chance of flipping the bike vs the scooter.
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Post by newslinky »

Eric as far as I know(No physicist here either) your post on physics is correct. tunseeker1 is also correct though in figuring the force involved in a crash you figure force on the rider seperate from force on the vehicle. So yes a scoot will do more damage and take more damage in a crash than a bike. The rider in both cases will be exposed to the same amount of force dependent on their speed and how much they weigh.
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Post by tunseeker1 »

OK sometimes my brain goes places that I don't like :?

Here is the latest!

If you are worried about the gear when you crash, is it ATGATT when out walking?

You could get hit by a car and that would really be a bad day. Think about the mass of the car that hits you!

In all seriousness in 2005 the EU changed the rules for car makers about pedestrian crashes to make it safer.

http://www.safetyresearch.net/Library/SRS037.pdf

And a good source of reading

http://www.erso.eu/knowledge/content/40 ... trians.htm
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Post by jmazza »

tunseeker1 wrote:The physics involved in a crash are dependent on only your body. A crash at 20 mph on skis, a bike, scooter or roller blades imparts the same force potential. The weight of the person times the speed is the force.The scooter can potentially take you to a higher rate of speed.

In a car, which has a lot more mass, you do not use the mass of the car to figure out the effect on the human body. This is why we have safety equipment in cars. Watch old videos about the secondary crash that happens inside of the car after a car comes to a complete stop in an accident situation.

This is the easy version of the physics question.
Well physics is certainly about as far away from my knowledge base as anything but it would seem that a major difference between car and scooter crash is that in a 20 mph car crash, even without a seat belt, you are not at all likely to end up sliding down the road. On a scooter, you've got about a 99% chance of sliding down the road in that same crash. And if you are still in riding position (somewhat and somehow connected to the scooter), wouldn't the scooters mass take you farther than if you were on a bike? And therefore wouldn't it be a factor (scooter mass) in the crash results?

If you get thrown, I get it totally- thrown from a bike at 20 and thrown from a scooter at 20= exact same crash. But I imagine the rider gets "tied" to the scooter in some way in many crashes/slides, which makes it seem logical (again to my VERY physics challenged mind!) that the scooter's weight should be factored in.

Am I at all on track?
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Re: Bicycle vs. Scooter Crashes and Physics

Post by jrsjr »

ericalm wrote:I've read a few posts in which members mention that they're cyclists and that they don't wear any more gear on a scooter than they would for a bike ridden at the same speeds.
Eric, I think there is a hidden assumption in your original statement which I want to dispute. Reading the above sentence carefully, I think the hidden assumption here is that somehow bicycle crashes aren't a big deal. In fact, folks get seriously injured (and killed) in bicycle accidents all the time. For this reason, I reject this argument out of hand.

Sorry if this seems OT, but arguing from a faulty initial premis is a great way to get weird results.
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Post by luckyleighton »

The physics involved are for both the bike/scooter and the other vehicle. I dont think there is an appreciable difference between a bike and a scooter going the same speed and having the same crash, other than the ease of flying off of a bike. The degree of the crash would more depend on the other vehicle (assuming it is a cage) because they are so much larger than you. One one side you have a 200lb scooter or a 50lb bike and they may create a difference in force, but the other side would make the ouchie just as bad.

IMO, a bike can reach some of the speeds a scooter can, but not all and not for extended periods of time. So for the gear question, I would ask myself the same questions, what is the chance I get in a crash and at what speed. It would not be the same answer on a bike, a scooter, or on a crotch rocket. I personally am comfortable without a jacket on a scooter, but not a crotch rocket for example.

About injuries on a bike, People do die on bikes all the time, I have heard of two in my area in the last year. There are many factors to accidents, I see many people on bikes who are unafraid of driving in traffic going much faster than them. Cagers also drive too close to bikers when passing as if they don't need much space. That's why they call it accidents, a small chance is still a chance of getting in a serious accident, we all take acceptable risk when riding.
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Post by kazoo »

I think as this thread grows larger we must remember that the OP was not trying to claim that riding a scooter is any more or less safe than riding a bicycle.

When I descend on my bicycle at speeds nearing 50 mph you can bet It would be safer to be on a scooter/motorcycle. In this statement I am of course ignoring the science part which includes mass and a body in motion... I'm thinking more in terms of design factor of the crate I'm straddling.

When I'm riding my biCyCle in traffic and I'm on the shoulder there is less chance the driver behind me will forget to apply brake pressure at the correct time.

And the examples can go on and on...
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Post by loodieboy »

So . . . given the gear typically worn by a bike cyclist (and the helmets don't seem to approach the level of protection offered by a motorcycle helmet?) . . . given the same accident at the same speed, isn't the risk of injury greater for the bike cyclist?
Clearly.
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Post by kazoo »

Its all true what you said; but it has been proven that the biCyClist will attract greater sympathy and hopefully better treatment. :)
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Post by sotied »

Just chiming in.

I used to race mountain bikes and there the only factors were your body's speed and the landing area (crash zone).

SO, think of both a bike and a scoot as the same thing if you're in a solo crash. Your body's speed is the only necessary factor if you get flung off the bike or the scoot.

BY THE WAY - a 50lb bike is the worst Wal-mart, pig-iron model. You would be hard pressed to find a bike that weighs more than 30lbs on the roads today and those are crappy hybrids. A good, entry-level road bike weighs between 22 and 24 pounds. If we are talking mass of the vehicle, that's 50% less mass than the supposed 50lb bike. OK, back on track.

Based on the design of the scoot vs. a bike, the rider should be ready for different injuries/impact.

A bike rider is perched atop two wheels with his mass often above the imact zone. Picture bike tires and the hood of a corvette versus a Buddy and the hood of a corvette.

The cyclist might flip in the air and land on his feet or butt while the scooter rider will likely slam into the headset, cruise across the hood and slide across the pavement.

Side of a truck, not much difference between the two.

Car door, bike guy gets slashed pretty severely while scooter rider might actually have enough vehicle mass to snap the door off and stay upright.

Pedestrian. Tumble for the bike. Bump and tumble and end up with scoot on top of you.

Head-on car. Bike rider into windshield or onto car roof or hood. Scooter, into the grille, hood or windshield.

I'm not advocating one way or the other - and I emotionally like the idea of being dressed for the speed of the vehicle, but position and things in your way are just a couple factors that seem to make the scoot more dangerous.

Just my $.04.
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Post by farrellcollie »

I have been in a couple of bicycle incidents (one on 16 lb road bike and one on 35lb hybrid). I had something flung into my spokes and was flipped over the handlebars on the roadbike going about 20 mph, landed on my head, cracked helmet, broke a wrist and two fingers and lost a lot of skin on my chin - very lucky not to have broken jaw. On hybrid - a car skidded through a stop sign on wet pavement and hit me - I fell to the side and lost some skin but no broken bones - I was going only about 8-9mph because I had just come from full stop and was proceeding through intersection. The only difference I would think had it been my scooter in the intersection is the possible difference in the scooter landing on me.
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Post by Quo Vadimus »

jmazza wrote:
But I imagine the rider gets "tied" to the scooter in some way in many crashes/slides, which makes it seem logical (again to my VERY physics challenged mind!) that the scooter's weight should be factored in.

Am I at all on track?
I agree. The forces only 'separate' if you separate from the scooter. If the scooter slides on top of you, you're going to slide as far and hard as the combined mass requires. If you're in a head-on collision, you may go over the handlebars, but you may not separate from the scooter (scooter rolls up the windshield/brick wall right behind you). You'd experience the stopping force of both.

However, let's also not forget the potential to rejoin the scooter. Let's go ahead and say a person stops with less force than a scooter. You start out traveling on the same trajectory, then become dislodged and slide. When you stop sliding, what's right behind you?

My minimal use of 'physics words' does not mean to imply knowledge of any kind. These are just descriptions of imagined situations.
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Post by illnoise »

I've always wondered about this, it's good to talk about. I think Eric's on the right track when you consider a crash where the rider stays with the bike, but most gear (aside from the helmet) is designed with abrasion resistance as a priority more than impact resistance. Assuming you're thrown off the bike, I'd imagine there's not a lot of difference. A cyclist is more likely to fall farther (sitting up higher).

I'd never be caught dead w/o a bicycle helmet, either. My brother's friend in high school died when he hit a curb at 15mph.

There's so much to think about here.

1) Your gear's role. Is it really saving you in a major collision, or preventing serious injury in minor-to-moderate collisions?

2) Vehicle awareness of bicycles vs. scooters/mcs

3) Skill, experience and confidence of cyclists vs. motorcyclists

4) Drivers' attitudes and stereotypes about cyclists vs. motorcyclists

5) Differences in risk in bikes and motorcycles

6) Differences in interaction with traffic in bikes and motorcycles

7) Differences in maneuverability and stopping power of bikes and motorcycles

8) Actual rate of injury death, as a percentage of those participating in the given activity.

I think #8 would be the biggest factor, if anyone can find those stats. Sure, pedestrians are killed by cars, and sometimes people fall down and crack their skull and die just walking down the street. But if the incidence of fatality is 1 in 100 million in pedestrians, one in a miilion in cyclists, and 1 in 500,000 in motorcyclists, that's good enough proof for me that I should be wearing gear. If it turns out that bicyclists have a higher rate than scooterists, maybe they *should* be wearing more gear.


Again, I refer all to the Hurt Report stats and use the typical mom "Don't worry about what they're doing, worry about what you're doing" line:

Wearing gear, taking professionally-taught classes, having a license, practicing regularly, etc. all reduce your odds of a fatal accident, by a very respectable margin. It's common sense, of course, but the figures are out there, and If I can cut my odds that dramatically with a few simple precautions, I'm gonna do it. No one should be allowed on a scooter until they've read the first chapter of Proficient Motorcycling.

As I say every time this topic comes up, choice is fine, but those choices shouldn't be made lightly, without any education on the subject.

From what I've seen, people wear more gear as they become more experienced. That irony should tell new riders all they need to know.

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Post by MarsR »

I think sotied is right on track with the position of the rider thing. The problem with the OP is that while the combined mass of the scooter/rider is greater than the combined mass of the bicycle/rider, the masses should generally be treated individually when talking just about injury to the rider (unless, of course, the rider is somehow attached to the scooter such as wearing a seatbelt. :o ) Even so, a more massive vehicle is actually an advantage to the rider during impact as long as it doesn't actually land on top of him. For example, a person driving an Chevy Tahoe is more protected in a crash than a person driving a VW Bug because the mass of the Tahoe is traveling with (in the same direction as) its driver.

I'm a MTGMTT guy. I believe that a crash on a scooter or bicycle won't be much different. But I typically travel about 15mph on my bicycle and I only wear a helmet and gloves for protection. But I'd really hate to crash on my bicycle while traveling downhill at 30mph.
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Post by kazoo »

I think what everone is saying is that when you mix flesh and bone with steel and concrete, you get hurt.

There are just way to many variables to even make a comparison, way to many.
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Post by jmazza »

kazoo wrote:I think what everone is saying is that when you mix flesh and bone with steel and concrete, you get hurt.

There are just way to many variables to even make a comparison, way to many.
I admire your ability to make this point in a very simple and concise way!!
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Post by EP_scoot »

I am not an expert on the laws of physics, but if you crash at say 20mph and your body leaves whatever is that it was riding (bike, scooter, skateboard, fast cow, etc) and your body hits the pavement . . . well, I don't think the pavement cares what you were riding. Once you hit it, your only protection would be that between the skin and the black top so the damage would be equal regardless what you were riding.

My worst skin rashes were always from falling off a bicycle as a kid as all I had were shorts, t-shits and light shoes.

I don't know, I rather dabble on truffles and high grade meats ! :wink:
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Re: Bicycle vs. Scooter Crashes and Physics

Post by ericalm »

jrsjr wrote:
ericalm wrote:I've read a few posts in which members mention that they're cyclists and that they don't wear any more gear on a scooter than they would for a bike ridden at the same speeds.
Eric, I think there is a hidden assumption in your original statement which I want to dispute. Reading the above sentence carefully, I think the hidden assumption here is that somehow bicycle crashes aren't a big deal. In fact, folks get seriously injured (and killed) in bicycle accidents all the time. For this reason, I reject this argument out of hand.

Sorry if this seems OT, but arguing from a faulty initial premis is a great way to get weird results.
I'm taking the statements others are making at face value. This isn't my claim or assumption; others have been saying this. What I want to figure is whether there's any rational or scientific basis to support the underlying logic of that claim. It's independent of the amount of injury that may result. I am questioning whether the forces involved are equal.

The Hurt Report (and personal experience) documented that serious injury is possible at slow speeds: The median pre-crash speed was 29.8 mph, and the median crash speed was 21.5 mph. "The likelihood of injury is extremely high in these motorcycle accidents-98% of the multiple vehicle collisions and 96% of the single vehicle accidents resulted in some kind of injury to the motorcycle rider; 45% resulted in more than a minor injury." I'm not trying to debate that at all.
sotied wrote:SO, think of both a bike and a scoot as the same thing if you're in a solo crash. Your body's speed is the only necessary factor if you get flung off the bike or the scoot.
What if you go into a slide? You're going to hit the ground harder on a scoot and it's going to slide longer/further so that if/when you become separated from the scooter you'll be traveling at a higher velocity than the bicycle.

When the bicycle or scooter collides with another object, your body is going to be subjected to greater forces while on the scooter even before you get thrown. I would guess that it's more likely that you get thrown completely and clearly off a bicycle because of rider position and because there's just less to stop you.
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Post by ericalm »

illnoise is right on by indicating that there are a lot more factors at work here. I suppose if trying to debate the logic of wearing the same amount of gear for a scooter as for a bicycle traveling at the same speeds, differences other than mass should be accounted for. I was hoping to make one simple point based on the fact that the vehicles have much different masses, but these things are rarely simple.
MarsR wrote:I think sotied is right on track with the position of the rider thing. The problem with the OP is that while the combined mass of the scooter/rider is greater than the combined mass of the bicycle/rider, the masses should generally be treated individually when talking just about injury to the rider (unless, of course, the rider is somehow attached to the scooter such as wearing a seatbelt. :o ) Even so, a more massive vehicle is actually an advantage to the rider during impact as long as it doesn't actually land on top of him. For example, a person driving an Chevy Tahoe is more protected in a crash than a person driving a VW Bug because the mass of the Tahoe is traveling with (in the same direction as) its driver.
The car analogies are much more difficult to suss out because there are even more variables involved. If you're treating the mass of the rider/driver individually from that of the vehicle then how is a more massive vehicle an advantage?

Take the Tahoe and a Bug. Let's ignore car interior design, location of steering wheel, etc. for the purposes of not over complicating this and assume that all factors other than mass of vehicle are the same. Drivers are not wearing seatbelts, airbags are disabled, brakes disconnected. Now drive each vehicle into a heavily reinforced concrete wall so that they each hit that wall at 40mph. Are you saying that the driver of the Tahoe will hit his steering wheel with less force than the driver of the Bug because the Tahoe has greater mass?
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Post by ericalm »

There are a number of science professionals and engineers over on MV so I posted a link there, hoping we can maybe get some more authoritative opinions on this topic.

I promise if it gets obnoxious, I'll shut my own thread down. :)
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Post by Scooter Hoot »

I believe everybody agrees that once you leave your vehicle, the only thing that matters is your initial speed. A person could have been taken to 30 miles by a tank, a pair of roller blades, a scooter, or a jet plane. It doesn't matter after you're separate.

The other equation that you need to consider is Acceleration = Change in velocity / Change in Time. The things that kills people is rarely skidding along the ground. Skidding, in terms of accidents is a GREAT thing - it makes the force that is applied to your body much lower. Impact - particularly head/neck impact is the biggest killer by far. If it takes you 5 seconds of skid rather than the .5 seconds of splat into a brick wall, you've decreased the force on your body by a factor of 10. This is why cars have crumple zones and airbags. It's all about trying to reduce the acceleration that your body experiences by buying precious fractions of seconds. Sure road rash hurts like nothing else, and you can still tear up joints, ligaments, etc, but you'll survive the trip to the hospital where they can stitch you back together.

That being said, my average speed on my bike is probably 12-15 mph. My average speed on my scooter is probably 35 mph. On my bike, I tend to ride through neighborhoods, on my scoot I ride down 4 lane in each direction roads. If I get in a high side crash, I'm flying down the road, and 280lbs of hot metal and plastic is going the same direction I am.

If I had to have a choice between a scooter vs bike crash - same speed, same gear, everything, I'd say bike. I'm an ATGATT person on the scoot, though, so it would be a toss up.
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Post by LisaLisa »

I think one of the issues is that it's far less practical to wear protective gear while cycling because you are exercising at the same time, and you need more flexibility and freedom of motion. And honestly, like hoot above, when I am cycling, I'm rarely going over 18 mph. And I don't ride particularly slowly. either, compared to my friends. I'm always riding over 25 on my scooter, and generally close to 45. When my bicycle is going 30, that means I'm scared.
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Post by robotribe »

illnoise wrote:From what I've seen, people wear more gear as they become more experienced. That irony should tell new riders all they need to know.
Eric linked this discussion over at modernvespa.com and since I'm a cyclist as well as scooterist/motorcyclist, I wanted to chime in. I can't agree more with the above quote. Why not just take the short cut to "smarter" (my opinion, I know) and gear up from the beginning vs. having to learn the hard way. I can't tell you how many times on modernvespa.com and various motorcycle boards I've read post-crash reports where the survivor reaches some epiphany as to how they're going to get better, more protective gear after suffering all kinds of nasty injuries that could have been prevented had they been wearing that full-face vs. a 3/4 helmet, or boots instead of sneakers etc.

As for bicycle riding vs. scooter riding from Eric's post on modernvespa.com:
L from Jersey wrote:Once you are riding in traffic, I feel that it's more dangerous to be on a bicycle
You can't keep up, you get even less respect from the cagers,
and there is no way you can wear proper gear
Precisely. Speaking for myself as a cyclist, I'd say there's no better way to introduce yourself to the world of scooter or motorcycle riding and how your just a moving target to cars, trucks etc. than riding a bicycle in/with/through traffic.

Like 'L' said, you can't wear the same gear on a bicycle and not pass out from heat exhaustion. The realities of cycling don't offer much by way of protective gear to the same degrees riding a motorcycle or scooter do.

Granted, the fastest I've gone on a bicycle is around 45 mph downhill, but that was just in races and on closed courses. Would it have hurt or worse had I crashed? Absolutely. But think about how rare that kind of riding is compared to getting up to 45mph on a regular basis and more frequently. Then take in to account the added weight and stopping power needed to for a 320-360lb scooter vs. a 17lb bicycle.

Both types of riding are inherently dangerous and risky, but in the end we mitigate our risks as best we can. Or, at least I hope we all do.
Like many others have already said, you can't ride a bicycle with the same gear you do on a motorcycle or scooter and expect to get very far without passing out. Also, getting up to speeds above 25mph on a scooter take a lot less time on a bike, therefore one could argue you have less time to react on a scooter than you do on a bike when you get to and above those speeds. For me, that's a good reason for a scooter or motorcycle rider to need "more" protection than a cyclist.
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Post by MarsR »

ericalm wrote:The car analogies are much more difficult to suss out because there are even more variables involved. If you're treating the mass of the rider/driver individually from that of the vehicle then how is a more massive vehicle an advantage?

Take the Tahoe and a Bug. Let's ignore car interior design, location of steering wheel, etc. for the purposes of not over complicating this and assume that all factors other than mass of vehicle are the same. Drivers are not wearing seatbelts, airbags are disabled, brakes disconnected. Now drive each vehicle into a heavily reinforced concrete wall so that they each hit that wall at 40mph. Are you saying that the driver of the Tahoe will hit his steering wheel with less force than the driver of the Bug because the Tahoe has greater mass?
You are correct if we are talking about crashing into a totally immoveable object. You would be injured just the same whether riding a 20 lb scooter or a 20 ton scooter. But I would suggest that most crashes don't include totally immoveable objects. Given a typical traffic accident and all other factors being equal (e.g., no airbags, no brakes, etc.), I would rather take my chances on the 20 ton scooter, because at the time of impact mass and inertia are on my side. Just don't let that 20 ton scooter land on top of you! :shock: :lol:
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Post by ericalm »

Scooter Hoot wrote:The things that kills people is rarely skidding along the ground. Skidding, in terms of accidents is a GREAT thing - it makes the force that is applied to your body much lower. Impact - particularly head/neck impact is the biggest killer by far.
Very true, but skidding does cause a lot of painful, non-fatal injury! And in the cased of ground toes and other digits, it's abrasion, not impact that does the damage.
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Post by bdarling »

MarsR has brought up the missing link in Eric's original post. Momentum is defined as Mass x Velocity. When two vehicles collide, the combined momentum is distributed between the two vehicles inversely proportional to their individual contributions. For a simple example, if a scooter (200#) and a Tahoe (2000#) are traveling at 30 mph and hit head on, the conservation of momentum equation says that the combined mass will be moving at 24.5 mph in the opposite direction that the scooter was traveling. If the crash is assumed to last for 0.5 seconds, this is about a 5g acceleration. Take the same crash between a 20# bike and said Tahoe and the combined mass moves in the opposite direction that the bike was traveling in at 29.4 mph. This works out to 5.5 g's. Not a significant change, but look at how much more energy the bicycle absorbed! The bottom line is that the added mass of the scooter works for you in a crash...if you stay attached. Now, the effects on your body are a whole different ball game and this is probably where the danger lies.
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sunshinen
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Post by sunshinen »

What jumps out at me is the braking power and maneuverability of the two vehicles. Even if both vehicles are going 25mph when an obstacle (oncoming vehicle, large pothole, leaping dear, etc.) is identified, the bicyclist is likely to hit with less force than the scooterist simply by virtue of applying the brakes. Consider trying to stop a Mac truck verses a SMART car.


Otherwise:
+1 on the average bicycle speed is actually much lower than the average speed on a scooter, no matter how fast you are on the bike
+1 on the idea that your interaction with cars is very dif on a scooter than a bicycle
+1 that cyclists' need to propel the vehicle provides a reason for limiting the gear worn that scooterists don't have
+1 on the notion that cycling is not exactly death and injury free — cyclists often do not survive accidents (and there are places I ride my scooter that I would never ride my bicycle)
kazoo

Post by kazoo »

jmazza wrote: I admire your ability to make this point in a very simple and concise way!!
And I admire your ability to locate this in me. I guess you aren't a bad guy afterall - Moderator. :)
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enzomatic
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Post by enzomatic »

very interesting post, I agree with everyone that there seems to be a too many variables in the type of crash and such. A coworker just recently hit the side of a car that pulled out on her bike, she was probably going 15-20, didn't have time to really break much, went over the hood, got some pretty bad road rash on her forearms, otherwise was fine. Bike was totaled though. If she was wearing a mesh jacket (if she would want to) probably would have been unscathed. Bdarling brought up something that I was considering, in physics you really have to be specific and isolate variables. If someone wants to play around with math, you can assume that passenger mass is 10kg for a bike, 100kg for the scoot, and let's say 1000kg for the car. and let's go with 35kph. and make this a direct interaction between these objects and an immovable object. Should we use elastic or non-elastic? We could then figure out the Joules of energy. start there then tack on the many other variables.
Looking for ppl to ride with in LA.
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