Anyone who needs to express this in the car scenes usually has something to make up for. But some thoughts:
Cars are very fast (in the non-technical sense of "can achieve high rates of acceleration") nowadays. Motorcycles are yet faster. Even a Harley will usually be able to hang with the non-exotic cars; a sportbike will match/beat a high-end Porsche to 100 mph depending on the drivers. Bicyclists are out of luck except for the first ten feet, where their low mass means they don't overpower their frictive surfaces.
While unmodified humans can accelerate themselves in excess of one g briefly, it's not very useful for travel. No stock cars, to my knowledge, exceed 1g forward accel. Lateral 1g has been achieved, and under braking it's certainly possible. Motorcycles are closer to 1g, but rarely do people post numbers for street bikes (it's much more dangerous to test, so it's usually only done for track bikes).
0-15 mph acceleration is very different than 60-90 (hence horsepower as a useful measure). Many SUVs can drag race my car to about 20 mph, at which point they probably lose completely. Personally I feel many SUVs are overgeared at low speeds (i.e. accelerate too fast), causing accidents as people overdrive their braking capability. None of this is useful in daily driving; what is useful is the 35-65 region, to merge onto highways, and the 60-80 region, to pass.
"While unmodified humans can accelerate themselves in excess of one g briefly, it's not very useful for travel. No stock cars, to my knowledge, exceed 1g forward accel."
Exactly. When you wrote, "Cars are very fat [...] nowadays," I worried that maybe the difference between the cars of twenty years ago and the cars of today was greater than I'd noticed, but I guess not. *whew* So yeah, if the race is longer than forty feet, a lot of humans will be in trouble. But in general the human will pull noticeably ahead of the car before the car starts catching up.
Note that I did not inclde motorcycles because I just don't know enough about them. From what you wrote it sounds as though a human can still be expected to have a greater peak acceleration than a motorcycle, but it may not be readily apparent to the naked eye watching the race in real time?
I don't think I've ever managed to get anywhere near the acceleration on a bicycle that I can on foot. (A technique issue? An equipment issue? Simply the expected result?) Then again, as you pointed out, running isn't nearly as useful for travel over meaningful distances as the other options are, in general. (Okay, time travel dumps you pre-automobile, needing to get a message across terrain too rough for a bike and not on a railway, and too urgent for walking and too far for one horse, and there's no relay station to change horses. Running is the most effective means of travel then. But I'd be willing to call that a "special case".) If I'm trying to get somewhere, rather than prove a point about peak acceleration and mammal muscles, I'll take a bicycle or an automobile, or walk instead of run.
But the reason I posted my question was to see how many people made what assumptions about the context, or complained about missing context. (If I'd wanted to be more scientific about this instead of just going for a Very Rough Impression, I would've made comments screened and been much more careful with phrasing.)
I'll admit it took me a minute of thinking it through before realizing you probably meant what you meant. What you said is a *very* common thought in, especially the motorcycle crowd where folks often respond to street challenges, so it took a minute to shake off the preconceptions.
Another note: this ratio may change suddenly with the introduction of electric-motored vehicles. Gas engines don't pull from 0 rpm, so you lose some time in the first segment to clutch slippage as you try to match >0rpm to 0mph. Electric motors, conversely, have full torque at 0 rpm. Given that some prototype cars have ridiculous 0-60 times (4 seconds?) they might be accelerating fast enough off the line to match a human.
Context
Cars are very fast (in the non-technical sense of "can achieve high rates of acceleration") nowadays. Motorcycles are yet faster. Even a Harley will usually be able to hang with the non-exotic cars; a sportbike will match/beat a high-end Porsche to 100 mph depending on the drivers. Bicyclists are out of luck except for the first ten feet, where their low mass means they don't overpower their frictive surfaces.
While unmodified humans can accelerate themselves in excess of one g briefly, it's not very useful for travel. No stock cars, to my knowledge, exceed 1g forward accel. Lateral 1g has been achieved, and under braking it's certainly possible. Motorcycles are closer to 1g, but rarely do people post numbers for street bikes (it's much more dangerous to test, so it's usually only done for track bikes).
0-15 mph acceleration is very different than 60-90 (hence horsepower as a useful measure). Many SUVs can drag race my car to about 20 mph, at which point they probably lose completely. Personally I feel many SUVs are overgeared at low speeds (i.e. accelerate too fast), causing accidents as people overdrive their braking capability. None of this is useful in daily driving; what is useful is the 35-65 region, to merge onto highways, and the 60-80 region, to pass.
Re: Context
Exactly. When you wrote, "Cars are very fat [...] nowadays," I worried that maybe the difference between the cars of twenty years ago and the cars of today was greater than I'd noticed, but I guess not. *whew* So yeah, if the race is longer than forty feet, a lot of humans will be in trouble. But in general the human will pull noticeably ahead of the car before the car starts catching up.
Note that I did not inclde motorcycles because I just don't know enough about them. From what you wrote it sounds as though a human can still be expected to have a greater peak acceleration than a motorcycle, but it may not be readily apparent to the naked eye watching the race in real time?
I don't think I've ever managed to get anywhere near the acceleration on a bicycle that I can on foot. (A technique issue? An equipment issue? Simply the expected result?) Then again, as you pointed out, running isn't nearly as useful for travel over meaningful distances as the other options are, in general. (Okay, time travel dumps you pre-automobile, needing to get a message across terrain too rough for a bike and not on a railway, and too urgent for walking and too far for one horse, and there's no relay station to change horses. Running is the most effective means of travel then. But I'd be willing to call that a "special case".) If I'm trying to get somewhere, rather than prove a point about peak acceleration and mammal muscles, I'll take a bicycle or an automobile, or walk instead of run.
But the reason I posted my question was to see how many people made what assumptions about the context, or complained about missing context. (If I'd wanted to be more scientific about this instead of just going for a Very Rough Impression, I would've made comments screened and been much more careful with phrasing.)
Re: Context
Another note: this ratio may change suddenly with the introduction of electric-motored vehicles. Gas engines don't pull from 0 rpm, so you lose some time in the first segment to clutch slippage as you try to match >0rpm to 0mph. Electric motors, conversely, have full torque at 0 rpm. Given that some prototype cars have ridiculous 0-60 times (4 seconds?) they might be accelerating fast enough off the line to match a human.