Discussion: Is speed really dangerous??

[David]

I have no data to back this up, but I bet the vast majority of vehicle fatalities are from people turning left in front of other cars with minimal relation to speed. Notice how many 'white crosses' you see at intersections or cross streets where you really couldn't go very fast.

[onewhippedpuppy]

Really, that's where the "all things being equal" disclaimer comes into play. Someone pulls out in front of you, the slower you go, the easier you can stop. Just physics.

We have a rural 4 lane that goes out of Wichita with many uncontrolled cross-streets, I'd say there's at least one fatality a month out there. Just pure stupidity. Stop signs on the cross-streets obviously don't mean much.

[the]

Originally posted by Overpaid Slacker
To restate what Matt said, more or less -- yes the inattentive/distracted driver is a key element of an accident, and probably the most common cause... but the likelihood of there being an accident, especially a serious accident, increases with delta V.

I'm zipping down the highway at 85 mph, and dfbroad, doing 80 mph drifts into my lane while using rearview mirror to apply fake eyelashes.

vs.

I'm zipping down the highway at 75 mph, and dfbroad, doing 50 mph drifts into my lane while using rearview mirror to apply fake eyelashes.

75 mph is "safer" than 85, no? And as long as dfbroad is dolling herself up, it's "safer" for her to do so at 50 than at 80, no?

But, the latter fact pattern is likelier to end catastrophically, no?

Delta Speed Kills.

JP

True, but speed itself kills, too.

If you get into a collision in your car with someone going half your speed, you will be fine if your speed is 5 mph. If you are going 120 mph in that same collision, you are likely going to die.

Same if you want to use an absolute number as the delta, say 25 mph. A 50 mph car v. 25 mph car is not going to be as damaging as a 125 mph car v. 100 mph car in the same collision.

[island_dude]

There is one other little detail that seems to be overlooked here. The momentum of your car increases with the square of the velocity. Stopping from 100MPH to zero much more than twice as long as from 50MPH to zero. The impact is much greater for a small increment in velocity. So, not only does your reaction time drop, but your ability to stop in a reasonably distance does too.

[epbrown]

Originally posted by VaSteve
Statistically, you spend most of you time near your home. Think about it.

I know that, but I think the key is that drivers are more distracted and complacent near home. I don't think driving 15,000 miles a year is more dangerous just because you own real estate in the area. I believe if the person drove 12k a year on the highway and the remaining 3k near their home, the latter would be the riskier because that's where people do their worst driving.

[masraum]

Originally posted by Overpaid Slacker
75 mph is "safer" than 85, no?

Yes. Inertia is increased, so if anything happens, the hit is going to be harder and more likely to damage the car or anything inside the car. In my book that makes it more dangerous. Also, because of the speed even a trained, skilled driver will have less time to react and less control, that also, IMO makes it more dangerous.

it's "safer" for her to do so at 50 than at 80, no?

Yes, being a dumba55 behind the wheel is safer at 50 than 80 for excatly the reasons above.

But I do also agree with the point that an idiot driver going 50 pulling in front of an attentive driver going 80 is more dangerous than if the idiot driver was going 75. So I agree with the quote below.

Delta Speed Kills.

I am also in complete agreement that the biggest problem is incompetent, untrained, unskilled, unconscious, inattentive, selfish, rude, overconfident, inexperienced drivers. Any and all of these things can make for a deadly driver.

So, speed does kill, it's physics. I have a hard time seeing how anyone can argue that. But that's not the biggest problem. The biggest problem is that the training here is a joke and the ease with which nearly anyone can get a car and/or license is a joke.

[Jims5543]

Doing 50 on a road where everyone is doing 80 (and the speed limit is 70) will be more dangerous though.

But if your doing 80 on a road where the limit is 45 then 50 is safer.

Speed kills, yes, but I am willing to bet most of the time the equation reads more like Speed + N = Death.

N can be anything pick one

tired driver
drunk driver
good driver finding a drunk driver
distracted driver
tire blow out
debri in road

[David]

Originally posted by onewhippedpuppy
Really, that's where the "all things being equal" disclaimer comes into play. Someone pulls out in front of you, the slower you go, the easier you can stop. Just physics.

I guess I should have said something besides "minimal relation to speed." I was thinking about 40-60mph roads where you have a good chance of being killed in a broad side accident whether the other driver is going the speed limit or 10-20 over. I'm really surprised by how many people don't look twice or three times before turning into an oncoming lane.

I don't see nearly as much danger in going twice the speed limit on a limited access highway versus 10 mph over the speed limit on a road with cross streets.

[ChrisBennet]

I used to drive horribly fast on public roads - I didn't pass people at those speeds but still, not the smartest thing to do. With experience comes wisdom - and wisdom generally comes from the close calls and near death experiences.

Depending you where you live you've probably seen dead deer on the side of the highway. Now use your imagination.

Where are you getting this "inertia increases as a square of the velocity" stuff?

Maybe you are thinking of energy as in E = 1/2mv^2 i.e. twice as fast = 4 times as much energy?

I suppose if you go twice as fast your brakes will have to dump 4 times as much energy (heat) but I don't know if that will effect your stopping distance - which is a function of your tires.

-Chris

[strupgolf]

"speed does not kill, stupidity does". I've always listened to that and always will.

[Moneyguy1]

Everyone posting here thinks of themselves as better than average drivers, I presume?

[epbrown]

Aren't 50% of all drivers better than average?

I don't know if I'd say we're all better, but I do believe that everyone on this forum cares about driving and wants to be good at it. That alone is a huge step towards being better drivers. Most people simply don't give a damn.

[austin552]

http://www.dailydemocrat.com/news/ci_6349159

[island_dude]

Chris,
Yep its energy that increases as the square of the velocity. Assuming that your brakes are at their maximum capacity without locking up, your stopping distance will increase by four times. In practical driving situations stopping distances will increase by some amount compared to driving slower. The point is that this is not a linear relationship. Once the brake system is at capacity stopping distance will be proportional to the amount of energy that is built up in the vehicle.

My point is that other than noting a reduction in reaction time, nobody has seized on this point. No matter how good your reaction times are, there is an increase in stopping distance and its not linear. That means a lot of folks are speeding along with a flawed idea of how much stopping distance they really require.


>Maybe you are thinking of energy as in E = 1/2mv^2 i.e. twice >as fast = 4 times as much energy?

>I suppose if you go twice as fast your brakes will have to dump >4 times as much energy (heat) but I don't know if that will >effect your stopping distance - which is a function of your tires.

[Dixie]

Very good buddy is a state trooper. "No matter what - never go off the road over 55" is his good advise.

Pretty good advice. For example, I've gone off-track at "The Kink" at CMP going around 100mph (backwards). Let me tell you. You go a looonnnnggg way through the grass before you stop.

[onewhippedpuppy]

Momentum = 1/2*m*v^2, good point. The fact that it is not a linear relationship between velocity and the energy that must be dissipated is a great point. You have twice the energy at 100 MPH than you do at 70 MPH, considering your brakes have a finite rate for dissipating energy, the effect on stopping distances is obvious.

[ChrisBennet]

Originally posted by island_dude
Chris,
Yep its energy that increases as the square of the velocity. Assuming that your brakes are at their maximum capacity without locking up, your stopping distance will increase by four times. In practical driving situations stopping distances will increase by some amount compared to driving slower. The point is that this is not a linear relationship. Once the brake system is at capacity stopping distance will be proportional to the amount of energy that is built up in the vehicle.

My point is that other than noting a reduction in reaction time, nobody has seized on this point. No matter how good your reaction times are, there is an increase in stopping distance and its not linear. That means a lot of folks are speeding along with a flawed idea of how much stopping distance they really require.


>Maybe you are thinking of energy as in E = 1/2mv^2 i.e. twice >as fast = 4 times as much energy?

>I suppose if you go twice as fast your brakes will have to dump >4 times as much energy (heat) but I don't know if that will >effect your stopping distance - which is a function of your tires.

You just can't "assume your brakes are at their maximum capacity" because it suits you. What would that mean anyway? You brake fluid boils? Not going to happen in a single stop even with crappy brakes.

Double your speed, double your braking distance.
-Chris

[Porsche-O-Phile]

No more or less dangerous than the backup created due to a highway full of "looky-loos" gawking over a cop having pulled over someone for doing 10 mph over the speed limit along with everyone else.

I wonder how many people have rubbernecked at a person pulled over for speeding, only to rear-end the person in front of them because they weren't paying attention. Probably more than PDs would ever admit. Oh, but that's okay - they want to back up traffic (and forget about the hazard created by having everyone distracted and slamming on their brakes and backing up traffic for five miles) - it's about "increasing police presence". That's more important.

Don't get me wrong - there's an appropriate time and place. Some jackass whipping in and out of lanes, riding two feet off peoples' bumpers and intimidating them with aggressive use of their headlights in their oversized, poor-handling, illegally modified "boy toy"? Damn straight they should get a ticket. Perhaps several. Someone driving drunk? Ticket. Wrong way down a one-way street? Most likely a ticket (or at least an inquiry into what the heck they're thinking). Running a stop sign or a red light? Ticket (unless there are BIGTIME extenuating circumstances). Accident? Ticket pretty much by default.

Just because some city bureaucrats have decided to put a sign on a strip of asphalt saying "35" or whatever doesn't change the de facto reality that if everyone and their brother can drive down that road for years at 70+ without a problem, that the speed limit is stupid, moot, irrelevant and probably a mistake.

Perhaps I (and others) would have a bit more respect for government, police officers, traffic laws and authority in general if it weren't so blatantly manipulated in the interest of insurance company interests and dollars, day after day after day after day after day. We all see it daily - a uniformed guy (or woman) who has dedicated their lives to public service and puts their lives on the line for the citizens they supposedly represent (whom we SHOULD be able to respect and thank for their service) forced into the role of tax collectors for dollar-drunk government do-nothing bureaucrats. That's a tragedy.

Speed is FAR less dangerous than differences in speed (as has been said). It'd be nice if on a three lane road, the speed limit was (for example) 40 in the right lane, 60 in the middle and 80 in the left. Or something to that effect. Of course, ideas like this will never fly, because we need to continue to dumb down our system for a society increasingly populated by stupider and stupider individuals with less cognition skill, less language skill, less analytical skill, etc. It'd be "too complex" for some retard illegal alien to make sense of, so it would never be considered.

Welcome to Amerika. Land of "the free".

[K9Torro]

From working Interstate accidents over more years than I care to count I have deduced the following :

It's not the SPEED that kill's , it's the sudden STOP at the end.

Todd

PS... I know the above is pretty simple but then I am a pretty simple kind of guy.

[scottmandue]

I always thought speed killed by shutting down your liver.