OT: Traffic accidents

Stan in Oly, WA

Well-known Member
I've been watching YouTube videos of car crashes. The vast majority of them seem to be from Russia where drivers apparently buy dashcams instead of car insurance. (There's a huge amount of road rage there, too. I suspect that alcohol plays a big part in both accidents and assaults.) A very common type of accident is on the freeway where one car sideswipes another, and the sideswiped car spins out of control hitting other cars, crashing into the freeway barriers, rolling over, etc. It often appears that the initial impact wasn't forceful enough to cause such devastating results so I suspect that the real cause of most of the wreck is over-correction by the startled driver of either car. The same thing often happens in single car accidents when a driver drifts out of his or her lane or drops two wheels off the shoulder and suddenly the car is crashing into barriers, running off the road, or rolling.

If a car is sideswiped by another vehicle of relatively similar weight, travelling the same direction, and at about the same speed, would the driver have a good chance of avoiding a terrible wreck by simply holding as steady as possible to the course the car was on?

Stan

P.S. Falling asleep at the wheel or taking your eyes off the road appear to not be good, either.
 
I like watching those Russian videos on Ridiculousness on MTV. The category is Russian Good Times. LOL
 

I see the main problem driving in Russia as being excessive speed, and second is passing someone who is slowing down for a valid reason and finding out too late what the other driver was slowing for.
 
I have seen.
635 turn into a parking lot.
Loop 12 become a bumper car zone.
The mix master turn into a war zone.
35 north and south slow to a crawl.
Have nightmares over Central.

Sure glad I moved.
 
I've watched some of those Russian dash cam videos! Scary stuff!

The video cams come into play as a weapon against scammers. Desperate losers looking to get into an accident, typically with a commercial vehicle, hoping to collect insurance.

Add to that lax licensing requirements and enforcment, alcohol, and just plain stupidity, makes for some interesting driving.

So many factors involved in the physics of an accident, hard to come to any real conclusion what to do. Watching professional race car drivers maneuver an accident is interesting.

Sometimes they make it, sometimes they don't. Even with their experience and skill, knowing just about what the other drivers are going to do, all vehicles equaly sized and equipped, and being on extreme alert at all times helps.

Those 4 factors are almost always missing in a real world bad situation.
 
I was heading north on 635 one day in Garland and a guy passed me going well over 100mph and the guy in front of me changed lanes in his path. He swerved to avoid hitting them and lost control of the car and spun 360 degrees somehow not hitting anyone. Then when he straightened out continued in excess of 100 again. I think I would have had to stop and change my clothes first. Looked like something you would see in the Indi 500.

635 has gotten so congested in the last couple years you can't use it anymore. I've had to start using side streets to get to University Park where I normally work.
 
I read/heard somewhere that it's nearly impossible to get insurance to pay unless you can "prove" the other guy was in the wrong. Seems the same goes for the legal system there. If you have it on camera, then the other guy's lies are null and void.

Many there also choose to forego insurance and eat any costs if they caused it or if truly accident, but have a camera just in case it's the other person's fault.
 
They can turn a profit making youtubes.

Insurance says NO FAULT
pay monthly
pay forever
NO FAULT
expect higher rates
monthly
forever
NO FAULT

just pay monthly
it wasn't your fault or theirs
Just make sure you pay the premiums
it's no ones fault

it's all rules of the contract
NO FAULT
and we reimburse as per contracted agreement

and raise rates
it's not your fault

hire a lawyer
the contract limits what you can get
and the lawyer too

it's nobody's fault
just pay monthly
 
Hmm. Nobody responded to your question.

When two cars sideswipe, it's going to impart some rotational force to one or both cars. And that may be enough to cause the tires to break traction. Once the tires break traction, they no longer steer the car at all, so the car will start to spin. And if the tires grab again, the car will go in whatever direction the tires happen to be pointed. It's not that much different than skidding on ice. So although I agree that overcorrection is a factor, for the most part if two cars travelling at different speeds sideswipe, they're likely to spin out.
 

Many posters here are unfamiliar with driving on winter roads . Summer tires, excess speed, lack of salt or sand on the road and traction is minimal . Just touch the brakes or steering and the driver looses control of the vehicle .
The dash cam is popular where proof of liability is an advantage . There are videos out there where someone on the street jumps out onto a wealthy appearing vehicle and they will smack their head into the windshield until they are bleeding . Then they sue .
 
It is still somewhat rural where I live (western R.I.) but nearby Providence and city area including several other towns now sort of merged into one big traffic mess. On the news it seems at least once a week, maybe more, someone drives off the road into a house or business. Got to be drugs, booze, cell phone. It used to be unusual when you saw a house with a car sticking out of it on the news but not anymore.
 
For many people, their first reaction is to brake aggressively hard. This is most likely the single biggest factor in their inability to keep the vehicle under control or to regain control. I learned back in the late 70's that your brakes are not always your best friend. My ex-wife would hit the brakes and hold them until the vehicle came to a stop, usual a ditch stopped her first.
 
I use to service generators. All over University Park and Highland Park. Did the UP police and fire station units.Simon David store. Mockingbird lane,Beverly Drive,Straight Lane,Preston Rd. I know all the back roads.

Back in the sixties. If you drove a pickup down Mockingbird. The police from UP and HP. Would follow through from the Dallas line to the other side of town and the other Dallas line. If you stopped at a house. They would be right behind you asking questions. Didn't want any poor folks in town. Certain folks had to have a letter from the family they worked for.
 
>It is still somewhat rural where I live (western R.I.) but nearby Providence and city area including several other towns now sort of merged into one big traffic mess. On the news it seems at least once a week, maybe more, someone drives off the road into a house or business. Got to be drugs, booze, cell phone. It used to be unusual when you saw a house with a car sticking out of it on the news but not anymore.

It's interesting that you mention this because here in PA we're noticing the same thing. It seems that once every week or so a vehicle crashes into a house or building. Someone just last week ask why do there seem to be so many vehicles crashing into buildings.
 
Another observation... it used to be a rare thing for there to be an crash that required the interstate highway to be closed. However, lately it seems commonplace for there to be 2 or more horrific crashes a week that require the interstate to be shut down for hours. I attribute it to folks driving C-R-A-Z-Y these days making it that any crash is likely to be a nasty one.
 
How about this...
There are very few accidents and many crashes.

An accident is when all involved drivers/vehicles are doing as they should and something goes wrong. A slippery patch of road, an animal runs out, a mechanical failure like a blown tire.

A crash is when one or more of the involved drivers/vehicles is doing something that they should not be doing - like speeding excessively, threading traffic, cutting off other vehicles, violating traffic control devices - and something goes wrong. This is not accidental! This is an idiot caught being an idiot.

To answer your question, it is likely that if both drivers avoided sudden maneuvers, a crash would likely be less severe. Until tires break traction, they will keep a vehicle on its intended path. Hard braking or sudden steering maneuvers will potentially cause tires to break traction. At that point, the skidding tire will try to take the lead. In the trucking world, the saying is that the skidding wheels lead the parade.
 
MarkB__MI;

Thanks for noticing and addressing my question. My fault, really, for burying the thing I wanted to know in so much superfluous text. I appreciated your recent answer concerning the nail puller.

Stan
 
ABS (Anti-lock braking system) is actually somewhat of handicap to drivers that know how to pull their car out of skid.
When I was a kid,cars often developed rod knocks. If the car was older it went to the scrap yard. My pal and I would buy a car,file the cap down or put meat rind under inserts,pour some heavy oil in crankcase then go play til engine blew. We learned quit a bit about handling skid,taking off and braking on slick surface.
If bottom feeding lawyers could be taken out of the picture,mud racing at tracks with rented cars could help drivers understand maneuvering icy streets and skids in general.
 
jimg.allentown; I agree with your definition of an "accident", and I appreciate the information you provided in answer to my question.

Stan
 

Stan, you didn't "bury your question", you put a blank space before it so it was very noticeable. However, there is no "answer" to your question, only opinions, because the term sideswipe is not a scientifically defined term. We all have an idea of what it could mean, but there could be a dozen different scenarios that you could call a sideswipe situation, and there could be forty different outcomes. I am happy for you that you liked markb's answer, you have the right to choose and name a winner. I think that there was still good entertainment in the thread, but I know from first hand experience that what markB said about the direction that the tires are pointed when traction is regained dictated the direction that the vehicle will go is incorrect just as often as correct.
 
We've had 4 fatalities in the past 3 years on I70 between the 4, 7 and 11 mile markers, all exits. Semi drivers involved are from Canada and some US drivers. Most of the time a car is crushed between two semis. One fatality, a Canadian semi driver died after he rear ended another semi. Accidents occurred while there was road construction and slow downs.
 
"ABS (Anti-lock braking system) is actually somewhat of handicap to drivers that know how to pull their car out of skid."

Agreed, I can think several times when I recovered from a skid because I had a rear wheel drive car (or truck) and knew how to do it with power-on oversteer.

Would not been able to do it with front wheel drive, and ABS would not have helped.

I spent hours as a kid learning how to handle a car in both two wheel and four wheel drifts, on (private) gravel roads and snow covered parking lots. Probably could not do so today without problems from the cops.

Dean
 
Things have certainly changed, I saw a guy panhandling at the corner of Inwood and Northwest Highway this afternoon. Easy walking distance to the super rich neighborhoods.
 
> I know from first hand experience that what markB said about the direction that the tires are pointed when traction is regained dictated the direction that the vehicle will go is incorrect just as often as correct.

Please explain that.

Either tires are rolling on the road surface with no slip (static coefficient of friction applies) and they are controlling the direction of the vehicle, or they are sliding on the road surface (dynamic coefficent of friction) and have little effect on the direction of the vehicle. There's no other condition. For all practical purposes the coefficient of friction between two surfaces is binary, either static or dynamic, with the dynamic coefficient being much less.

What I didn't say is that all four tires don't necessarily grab at the same time. If the front wheels grab first, they dictate the direction of travel. If the rear wheels grab before the fronts, then the vehicle will travel in the direction it is pointed, not the direction the front tires are pointed.

Now there is an exception, and that's when the vehicle's center of gravity is high enough that it rolls over when the tires grab. An interesting special case of this is with rear-wheel lockup on a motorcycle. If you lock up the rear brake on a bike, the bike will yaw as the rear wheel slides sideways relative to the direction of travel. Releasing the rear brake will cause the back tire to grab, with the result that the bike will try to instantly change direction while upright, resulting in the dreaded "high-side" crash. That's why motorcyclists are taught to keep the rear brake locked up until a full stop if they ever do lock it up. (Motorcycle ABS is a huge lifesaver for this reason.)
 
(quoted from post at 04:32:56 03/19/19) > I know from first hand experience that what markB said about the direction that the tires are pointed when traction is regained dictated the direction that the vehicle will go is incorrect just as often as correct.

Please explain that.

Either tires are rolling on the road surface with no slip (static coefficient of friction applies) and they are controlling the direction of the vehicle, or they are sliding on the road surface (dynamic coefficent of friction) and have little effect on the direction of the vehicle. There's no other condition. For all practical purposes the coefficient of friction between two surfaces is binary, either static or dynamic, with the dynamic coefficient being much less.

What I didn't say is that all four tires don't necessarily grab at the same time. If the front wheels grab first, they dictate the direction of travel. If the rear wheels grab before the fronts, then the vehicle will travel in the direction it is pointed, not the direction the front tires are pointed.

Now there is an exception, and that's when the vehicle's center of gravity is high enough that it rolls over when the tires grab. An interesting special case of this is with rear-wheel lockup on a motorcycle. If you lock up the rear brake on a bike, the bike will yaw as the rear wheel slides sideways relative to the direction of travel. Releasing the rear brake will cause the back tire to grab, with the result that the bike will try to instantly change direction while upright, resulting in the dreaded "high-side" crash. That's why motorcyclists are taught to keep the rear brake locked up until a full stop if they ever do lock it up. (Motorcycle ABS is a huge lifesaver for this reason.)

Mark, consider this: rounding a sharp curve, at a speed that puts you at nearly the limit of sideways traction all four tires are rolling BUT, they are rolling with sideways push. THEN, you encounter a patch of ice that eliminates the sideways traction of your two right side tires. Immediately your two left tires will loose sideways traction and though still rolling, will ALSO slide sideways. The tires are rolling, they are pointed down the road and are sliding sideways. Now this brings us to my basic point. in an accident the forces at work on each vehicles traction vary virtually INFINITELY as time progresses and vector forces change. While it is true that a rolling tire will exert some directional force and will steer a vehicle to a degree, The inertial force of the vehicle sliding in one direction at say fifty MPH cannot change to lets say a course of 45 degrees to the left just because the driver releases the brakes and the tires start to roll again. Slow the vehicle to say 25 MPH and the tire direction will probably take over again. The direction that the tires are pointed certainly has an effect but that effect varies greatly according to the forces at play. Which is also why Stan's original question is not answerable to any meaningful degree.
 
People tend to stand on their brakes as a first reaction to any problem. That then removes any chance to drive out of a problem. Many roll overs on 80/90 that runs past my farm from people blowing a tire and slamming on the brakes rather than just letting the car slow down to a stop.
 
Few minor points.
-Tires have a slip angle proportional to the steering forces they are under. The tire never travels along the static friction ideal route unless it is under no cornering force.
-Under and oversteer happen when those slip angles don't match
-There is a big change in slip angle when it transitions from a proportional to force, increasing slip while rolling, when it drops to fairly non-proportional while sliding.

When you transition back from sliding to rolling, there's a huge increase in the forces about the centre of mass of the vehicle (a moment) and it can turn the car about the centre of mass fast enough for the other set of tires to pass from sliding to rolling and right back into sliding the opposite way. All sorts of funny things happen when the forward speed drops enough for the tires to reenter rolling while the vehicle is still sideways.

Used to be easy to tell people unfamiliar with skids winter driving, if you can't counter steer properly, just lock up the brakes hard and you'll understeer and sail straight along the line you were on until you slow down or hit the snowbank. Now ABS lets the wheels roll back them head on into oncoming traffic when they drop to about 15 mph and all kinds of other silly stuff. I will say some of the newer stability control vehicles with winter programming are amazing. Very boring to drive but go into a patchy icy/snow/bare pavement turn way too hot? Gently understeers despite varying surfaces, will not let you get crossed up too far mid turn. Very annoying that a computer will let you get around a bad turn faster than hundreds of hours of practice on terrible roads.
 
(quoted from post at 14:47:40 03/18/19) "ABS (Anti-lock braking system) is actually somewhat of handicap to drivers that know how to pull their car out of skid."

Agreed, I can think several times when I recovered from a skid because I had a rear wheel drive car (or truck) and knew how to do it with power-on oversteer.

Would not been able to do it with front wheel drive, and ABS would not have helped.

If you'd had a front wheel drive car with ABS, you never would've been in that situation to begin with.

My folks were like that for many years, stubbornly refusing to buy a modern front wheel drive car, buying Impalas and Caprices until GM stopped making them and the newest ones left were too old to be viable. Then they got their first front wheel drive car. It was like night and day. The car actually went where you steered it on a snowy road instead of having to constantly countersteer! The car actually WENT on a snowy road instead of spinning! The car actually STOPPED on a snowy road instead of having to pump the brake pedal and pray!

Yes, it took different driving techniques. Countersteering a FWD car is a good way to end up in the ditch. Pumping an ABS brake pedal is a good way to end up sailing through an intersection. With a FWD car you steer in the direction you want to go and accelerate. With an ABS car you STOMP and STEER on a slick surface. It requires change, which some simply can't manage.
 
Today's wreck was unusual to say the least. There was a three car pile up in a turning lane to a residential street on Buckner.
 
Ken, thanks for your comments. You clearly know more about vehicle dynamics than I do. Your point about slip angle when cornering is a good one; I admittedly oversimplified.

But I think my point is still essentially correct: either the tires are directing the vehicle's direction of travel, or they're not. And the transition between the two tends to be abrupt.
 
> Agreed, I can think several times when I recovered from a skid because I had a rear wheel drive car (or truck) and knew how to do it with power-on oversteer.

Hmm. That sounds like something the nineteen-year-old me would have said to his buddies while drinking 3.2 Coors at the local pub.
 
(quoted from post at 13:09:20 03/17/19) I've been watching YouTube videos of car crashes. The vast majority of them seem to be from Russia where drivers apparently buy dashcams instead of car insurance. (There's a huge amount of road rage there, too. I suspect that alcohol plays a big part in both accidents and assaults.) A very common type of accident is on the freeway where one car sideswipes another, and the sideswiped car spins out of control hitting other cars, crashing into the freeway barriers, rolling over, etc. It often appears that the initial impact wasn't forceful enough to cause such devastating results so I suspect that the real cause of most of the wreck is over-correction by the startled driver of either car. The same thing often happens in single car accidents when a driver drifts out of his or her lane or drops two wheels off the shoulder and suddenly the car is crashing into barriers, running off the road, or rolling.

If a car is sideswiped by another vehicle of relatively similar weight, travelling the same direction, and at about the same speed, would the driver have a good chance of avoiding a terrible wreck by simply holding as steady as possible to the course the car was on?

Stan

P.S. Falling asleep at the wheel or taking your eyes off the road appear to not be good, either.
I get a little nervous at red lights watching the driver who is coming up behind me.
 

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