Is 80MPH to fast too drive on a freeway?

[bluestrobe]

6 months to have a license isn't much and there?s plenty to learn. So yes, 80mph is a lot in a grocery getter at your age.

 

[feelingshorter]

i do things if its economical and driving that fast means your engine is probably not running efficiently...so no..i hate paying 20 dollars for gas each week

 

[SithSolo1]

Originally posted by: narcotic

Originally posted by: SithSolo1
I hit 115mph entering the loop around town yesterday. It was either get out ahead of the wall of cars or come to a complete stop and die trying to merge into 65+mph traffic.

Oh, so you're one of these guys we see on "COPS"...

Not yet but I'm working on it...just look for the blue car to turns into a fireball as it hits a bridge doing 140.

 

[kevinthenerd]

Originally posted by: sdifox
If your speed is not above 120KMPH (about 75mph) on the 401 here in Toronto, you could get rear ended. 80mph is nothing if the road is dry. I've done 100mph on a 1990 Camry V6 and it was getting scary since it started to float.

Sounds to me like a poor alignment or it was windy outside.

 

[kevinthenerd]

Originally posted by: jagec

Originally posted by: gsellis
I am trying to remember the parameters to the equation. I think they are 1/8" of water on slicks. The hydroplaning speed is 9*(tirepressure(psi))**.5 So, 36psi yields 54mph for where you are skating on water with junk tires with just a solid film of water on the road. Consider that in a heavy rain on those junk tires.

I would imagine the width of the tires and weight of the car have SOME effect...

Not really... The tire pressure is proportional to the weight of the car divided by the area hitting the pavement. (Assume the tire is a non-rigid bladder.) Most tires have a pretty consistent aspect ratio when they hit the pavement, so a general rule like this may apply. I can't vouch directly for it, though.

I might be able to figure this out in a minute or two if I sit down and figure out the mass transfer.

 

[kevinthenerd]

Originally posted by: jagec

Originally posted by: EXman
Well 80 in a 55 is wreckless driving and you go to JAIL. I'd say that is a crime.

yup 75-80mph are pretty normal on all interstates not just socal. But I've seen my mpg go up from slowing down the speedo some.

They put you in jail for not causing wrecks?

30 over is jailtime in Florida, so you'd have to do AT LEAST 85 in a 55 to see handcuffs and bars. If you're driving REALLY fast, though, (like 70-80 over) a lot of cops won't bother trying to catch up to you because it's more dangerous for them to follow you in their crappy Crown Vic interceptors.

(I want a fast car SOOOO badly! I'm currently working on designing a tube-chasis race car for the street that'll roast just about anything.)

 

[kevinthenerd]

Originally posted by: shoRunner
80? come here to atlanta and you'd better be in the slow lane with that crap

If you're in Atlanta and see a shiny gray blur pass you like you're going backwards, it might be my friend's tricked-out Passat going flat-out to lose another cop.

 

[kevinthenerd]

Originally posted by: giantpinkbunnyhead

Originally posted by: wetcat007

Originally posted by: Cruisin1
Who isn't going faster than 80 on the freeway?

Those who are going 90.

WTF? How can one do 90 without going faster than 80? *scratches head*

Define "faster." This is some kind of paradox.

 

[Aves]

That's only 10 miles over the limit here.

 

[kevinthenerd]

Originally posted by: OCNewbie
I would do 80 all the time, but I get paranoid about cops. This is in the Orlando area. Parts of town are really dumb though. On I-4, the speed limit will be 50 or 55, depends on the area, and everybody does at least 65, and 70-75 feels peachy keen, doesn't feel at all too fast for the road conditions, visiblity, etc. And that's like 20-25 over the speed limit. I see cops doing 65+ in these 50/55 zones as well all the time, with cars driving right next to them, and they never pull anybody over. Now, pass that same cop that's doing 65, at like 70, and I bet he does =)

I'm in Orlando myself. I swear I-4 must be a goldmine for speeding tickets, but I've never had one. You gotta watch where the medians are. Cops like to hang out where there aren't any median barricades. I go about 85 between Millenia and Disney, but I sure as hell wouldn't do that in the heavy construction area in Lakeland. 408 is nice, especially between 417 and 50 where it's a poorly-patrolled 65. (I've topped it out a few times in there.) 408 between 417 and downtown is a b¡tch, though, because the constant little hills always have cops on the bottom.

 

[kevinthenerd]

Originally posted by: 0roo0roo
just double your following distance. but people are stupid and don't

Good call. In most rural areas, I see rednecks with their big diesel trucks following so closely that you'd think they were trying to save fuel. Are they trying to intimidate slow drivers or something? I used to get a little nervous when I saw a big grill fill my rear view, but now it just motivates me to brake-check the bastards.

 

[kevinthenerd]

Originally posted by: glugglug

Originally posted by: booradley
The most efficient point for a car is a shade above idle in top gear. On a mainstream car, this is certainly below 60mph, espicially with the wealth of 4 speed automatics in America.

The only car I've ever driven where 60mph was in top gear was a Geo Metro. In fact, my old Bonneville would be in FIRST gear at 60.

I have a 2003 Saturn ION with the 5-speed Aisin automatic. (The 2005+ models are only available with a Getrag 5-speed manual and a Hydromatic 4-speed auto.)

My shift points at wide-open throttle:
1st-2nd - 35 mph (approximately... the spedometer doesn't keep up properly, and it shifts before redline)

2nd-3rd - 55 mph

3rd-4th - 85 mph

4th-5th - 100 mph

This is why I believe my car has such a crappy 0-60 time, yet it smokes Civics: It is in a MINIMUM of third gear when doing 60. Cars like the Ford GT, for example, are still in first gear. If I can get some internal work done on the motor, I might be able to run it at higher rpm's and change the transmission shift points at WOT, but that isn't going to be for a while.

 

[kevinthenerd]

Originally posted by: adwilk
I love how this became a pissing contest... i drive 432mph+ everywhere I go. BS

I drive 433, biotch.

 

[kevinthenerd]

CLIFF NOTES BELOW

Originally posted by: Tom
I'm guessing here, I don't feel like looking up the facts, but danger is probably exponentially related to speed, particularly when you exceed the design criteria for the highway, the conditions, and the equipment being operated.

By driving 80mph, at night, on most US highways, with most vehicles, you are probably exceeding the design specifications for the highway and the vehicle, and the odds of a fatal accident are much higher than they would be driving 60.

I would guess 4 to 10 times greater.


some design specs I'm basing this on
highway
barrier and median design, lane width, curve radii, road surface, road maintenance, signeage and pole design, berm/curb design.

vehicle
seat design, seat belt design, lighting, crumple zones, tire rating, braking distance, rollover protection, fuel tank design, occupant protection(helmet, gloves, flame resistant clothing), secondary collision impact(dash padding,etc), airbags.

Let physics lend a hand to your armchair bullsh¡t...

The acceleration around a curve:

a = v^2 / r

In other words, the acceleration you are going to experience around a turn is equal to the square of your speed divided by the radius of the turn. (Keep it simple: I'm purposely avoiding the proof in vector calculus.)

So, if you speed around a turn at 50 mph and experience a sideway tug at 1/2 that of gravity, a relatively high-end sportscar (rated at 1 g on the skidpad) would have problems negotiating that turn at only 70mph, not 100. At 100 mph, you would have to have racecar handling characteristics to stand a chance: 2 g's on the skidpad. Most cars are only rated around 0.8 g's on the skidpad, and those numbers are obtained by professional drivers for car magazines.

Now, let's look at another important aspect:

W = F x

KE = (1/2) m * v^2

W = KE

F = uN

(Again, ignoring calculus and vector operations...) The work-energy principle says that the energy you apply to an object is equal to the force you apply to it times the distance over which that distance is applied. The kinetic energy of an object is equal to half of its mass times the square of its speed. By the conservation of energy, the amount of kinetic energy in an object is equal to the amount of energy it takes to stop it. The force of friction on a surface, by a common engineering simplification (which doesn't always apply to tire mechanics), is equal to the coefficient of friction times the normal force, which is the force squeezing the two objects together. This force is equal to the gravitational force in this case, N = mg

Putting this all together:

(1/2) m * v^2 = umg * x

masses cancel...

(1/2) v^2 = ug * x

x = ( (1/2) v^2 ) / ug


CLIFF NOTES:

Both stopping distance and cornering ability are proportional to the SQUARE of the speed. Doing 100 mph is four times more dangerous than 50 mph in most cases. This, however, doesn't take into account driver reaction times, which are more likely to be improved at high speeds (at least for me). I get bored when I drive slow. Driving fast helps me to pay attention because I spend so much of my mental energy looking for cops. (I have zero points on my license, which is a flawless record in the state of Florida, so something is obviously working for me.)

 

[preslove]

My grandpa would egg me on to go over 100 mph on the back roads. "There is no turn on this road that you can't safely take at a 100 mph." "Push it." That's my favorite memory of him

 

[kevinthenerd]

Originally posted by: PaperclipGod
I commute daily at 90-120mph. Going to class in the morning is like driving a short leg in the dakkar rally through traffic.

One time a cop tried to pull me over, but i launched my car to the side of the road and stopped so fast he flew by me. It was the end of the breakdown lane so he couldnt stop up ahead either. I was lol'ing about it for the rest of the day.

I need to get some good tires and some good brakes and try that myself!!!

 

[kevinthenerd]

Originally posted by: preslove
My grandpa would egg me on to go over 100 mph on the back roads. "There is no turn on this road that you can't safely take at a 100 mph." "Push it." That's my favorite memory of him

My grandfather invented the motor home. He built his own before they hit the market!

He built his own racecar. His hand-built racecar competed successfully with sophisticated European cars costing many times more.

I miss him.

 

[PaperclipGod]

Originally posted by: kevinthenerd
This, however, doesn't take into account driver reaction times, which are more likely to be improved at high speeds (at least for me). I get bored when I drive slow. Driving fast helps me to pay attention because I spend so much of my mental energy looking for cops. (I have zero points on my license, which is a flawless record in the state of Florida, so something is obviously working for me.)

Good point.

When im driving fast, im constantly evaluating the road environment. Watching other cars, the road condition, upcoming corners, breaks in traffic, on/off ramps, merging traffic, etc. When im going slow, i sort of zone out and just stare at the bumper in front of me.

Putting it in that light, driving at any speed is probably equally dangerous.

 

[Tom]

Originally posted by: PaperclipGod

Originally posted by: kevinthenerd
This, however, doesn't take into account driver reaction times, which are more likely to be improved at high speeds (at least for me). I get bored when I drive slow. Driving fast helps me to pay attention because I spend so much of my mental energy looking for cops. (I have zero points on my license, which is a flawless record in the state of Florida, so something is obviously working for me.)

Good point.

When im driving fast, im constantly evaluating the road environment. Watching other cars, the road condition, upcoming corners, breaks in traffic, on/off ramps, merging traffic, etc. When im going slow, i sort of zone out and just stare at the bumper in front of me.

Putting it in that light, driving at any speed is probably equally dangerous.

What state do you guys live in ? I'd like to avoid driving there..

 

[hytek369]

No

 

[PaperclipGod]

Originally posted by: Tom

Originally posted by: PaperclipGod

Originally posted by: kevinthenerd
This, however, doesn't take into account driver reaction times, which are more likely to be improved at high speeds (at least for me). I get bored when I drive slow. Driving fast helps me to pay attention because I spend so much of my mental energy looking for cops. (I have zero points on my license, which is a flawless record in the state of Florida, so something is obviously working for me.)

Good point.

When im driving fast, im constantly evaluating the road environment. Watching other cars, the road condition, upcoming corners, breaks in traffic, on/off ramps, merging traffic, etc. When im going slow, i sort of zone out and just stare at the bumper in front of me.

Putting it in that light, driving at any speed is probably equally dangerous.

What state do you guys live in ? I'd like to avoid driving there..

Just dont putter along at 60 in the passing lane and youve got nothin' to worry about.

 

[Slacker]

80? GTF out of my way.

 

[Sunbird]

Wooses :roll:, I go back in time a lot cause I keep going faster than light!