Wrecked

[marleyfan]

ABS will not enable you to control a vehicle in all situations. Saying that even tho I had ABS I still lost control does not mean that ABS is not worthwhile or does not make a difference in most situations. ABS will make a significant difference in many situations, no difference in some, and may be a detriment in a few. When you weigh the pros and cons of ABS the pros win.

[proxim2020]

Marleyfan is correct. ABS will not save you in every condition. In previous topics, I've stated situations where ABS wouldn't be very useful. In situations where you have a loose gravel road or snowy roads, ABS will actually increase stopping distance and may even cause you to lose control. In these situations, locking the brakes is the best thing you can do. Locking the brakes will cause the loosely packed material to create a wedge underneath the tire and help bring your speed down in a hurry. If you have a lot of unpaved roads or you live in a climate where you get lots of snow year round, think carefully about ABS.

I also agree with Marley that when you weigh the options, ABS win for me. Rarely do I get snow where I live and rarely do I travel down loosely packed roads. Most days it's just dry highway. You don't want to have to lock 'em up on dry pavement.

I would like to also point out that ABS performs differently on different cars on it is not the be all end all of safety features. Educate yourself on the ABS in general and then on the system installed on the car (test drive in a panic situation). Then make the decision if ABS fits the bill for you. Learn how to drive you car in any situation no matter if you have ABS installed or not. Like EV pointed out in the past, you're not automatically safe just because you have ABS. You'll also need to learn how to drive with it.

[DocPlez]

TASK. Some drivers learn the rule of thumb, "Follow two car lengths behind for every 10 miles per hour." Others learn, "Stay two seconds behind the car ahead." Do these two rules give the same results? Is one safer than the other? Is one better for roads with speed limits of 45 or 50 miles per hour and another for highways on which the speed limit is 65 or 70 miles per hour?

COMMENTARY. Obtaining a driver's license has become one of the "rites of passage" in the U.S. On almost every written driver's test, applicants are asked how closely one driver should follow another on the highway. We all appreciate the dangers of tailgating--not enough stopping time and not enough space to avoid an accident. However, it is not clear that there is agreement about what actually constitutes tailgating--how far apart cars should be.

Rules of thumb are helpful guidelines--sometimes derived from experience--that are calculated using easily available measurements. Often they are developed under particular conditions and may be extremely inaccurate if those conditions are not fulfilled. The existence of two rules of thumb for the same situation suggests a natural question: Are the two rules simply two different ways of saying the same thing or are they offering different advice? As stated, the rules may provide visual images of how far to stay behind another car, but translating that understanding into practice on the road may be quite a different matter. The exercise of interpreting rules of thumb and comparing their results with real data could help students realize that the rules they use have implications for their actions. Also, there is the reality of high incidences of automobile accidents among new drivers. This exercise may help students examine and improve their driving habits.

In order to do the task, students need to know what it means to make a comparison. They have to identify the quantities needed in order to calculate the following distances given by the two rules and represent the rules mathematically. There are many ways to do this--written descriptions, tables, equations, or graphs, all basic tools of mathematical literacy. A comparison requires that the two representations use the same units of measurement--hence some conversions are necessary from the units used in the original rules of thumb. Such conversions are an essential part of many everyday situations, both at work and at home.

MATHEMATICAL ANALYSIS. To begin, students might be well advised to consider the case in which two automobiles are traveling at a steady rate. The information presented is not complete and students will find that they have to seek out missing data. Naturally, what students seek will depend on their interpretation of the task. One necessary piece of information may be average car length.

The units for the car-length rule are miles per hour and car lengths, and the units for the two-second rule are miles per hour and seconds. To compare the two rules, both need to be written in the same units. A typical sedan is about 14 feet, so the car-length rule might be translated as "follow about 28 feet behind for every 10 miles per hour" or as the equation y = 28(x/10), where x is the speed of the car in miles per hour and y is the following distance in feet.

If a car is traveling at x mph, then it travels x miles in one hour--in other words, x/3600 miles in one second. The two-second rule is then "if your speed is x mph, follow about 2x/3600 miles behind." As an equation, it is z = 2(x/3600), where x is again the speed of the car in miles per hour, but this time z is the following distance in miles (not feet as in the previous equation), and we use a different letter to distinguish it from y above.

Now the rules are both in terms of miles per hour and units of distance but not the same units of distance. The car-length rule is as follows:

y = 28(x/10),

where y is the following distance in feet. The two-second rule is

z = 2(x/3600),

where z is the following distance in miles. Simplifying the car-length rule gives

y = 2.8x,

where y is the following distance in feet. Simplifying the two-second rule gives

z = x/1800,

where z is the following distance in miles.

Now it's a matter of converting z to feet (or y to miles). There are 5,280 feet in a mile, so x/1800 miles is 5280(x/1800) feet. That's about 2.93x feet--very close to the distance given by the car-length rule!

Some driver's manuals give data on the distance cars travel before they are able to come to a complete stop. Often the distance is broken into two components, the reaction distance and the braking distance. The reaction distance is the distance traveled while the driver reacts to a situation and hits the brakes. The braking distance is the distance traveled from the time the brakes are applied until the car comes to a stop. A simplified version is given in Table 1.

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Table 1: Reaction and braking distances for various speeds Speed Reaction Distance Braking Distance 20 mph 20 feet 20 feet 30 mph 30 feet 45 feet 40 mph 40 feet 80 feet 50 mph 50 feet 125 feet 60 mph 60 feet 180 feet Bottomline ... too fast for road conditions and/or following too close. Sorry for the simple high school math but come on people ... calculus wouldn't have helped prevent this. If I recall correctly you were following 4 - 6 car lengths behind?? That's 80 to 120 feet if your consider and average car to be 20 feet ... in the case of our Versa that's what 52 to 78 feet?? On wet roads? Yes, Nissan may need to work the brakes a bit and the tires may not be Z rated for 200 miles per hour but know your cars limitations and drive accordingly and we'd be complaining about something else. I failt o see how the Versa is responsible for this at all.

Doc

[Ever Victorious]

And for what it's worth, when I was going through driver's ed a little over a decade ago, we were taught 4-6 seconds, not 2 seconds, not carlengths of any type.

The reasoning for this has a lot to do with reaction times and sympathetic stopping distances... or not having to rely on them, more specifically.

Sadly, drivers around here don't often give me the chance to have that much following room. I'd much rather get there safely (especially after my recent accident) so I usually end up driving slower in general and letting people pass me. Usually pissed off at me, but whatever.

Now... as far as carlengths vs. feet/second...

Carlengths are a constant, since a car does not get larger at higher speed. An average car is 18 feet in length (Versas are just under 15... Cadillacs can be in the 20's... most SUV's are actually shorter end-to-end than you would think). So two carlengths is about 36 feet, four is 72 feet. Very short distance

SECONDS of distance is a variable at speed (sorry, Doc... if you had a speed variable in your seconds equation, I did not see it... so I had to post my piece here). You are traveling 2.03 feet per second at 1 MPH so following distance at seconds is T x V x 2.03... where T equals time in seconds and V equals velocity in miles per hour.

So a 4 second following distance at 60 mph is then 487.2 feet. A much, MUCH safer following distance.

For the Canadians:

2 carlengths of stopping distance is approximately 10 meters.

The mathematical representation of following distance in seconds is as follows: you are moving 0.27 meters every second at 1 kilometer per hour. T x V x 0.27 is stopping distance in seconds at a given speed in Km/h.

So a 4 second following distance at 100 Km/h is 108 meters.

[DocPlez]

Not a problem EV I was trying to use the KISS principle as math confuses many it seems.

If you wish to talk about stopping cars I just bought a 1956 Chrysler Windsor which is heavy as h%ll and stops in yards and 1/10ths of miles not feet. I've had to up to 110 miles per hour "just to check it out of course" but stopping it requires a bit of forethought and planning. Panic stopping is out of the question ... that's why it was built of steel I'm sure. Air bags are laughbale for this car ... it didn't even come with seat belts.

Doc

[DocPlez]

PS .... amazingly enough they were teaching the same principle when I went through Drivers Ed 31 years ago this year. Must be something to it!!

Doc

[jroot]

There seems to be a lot of Aholes around here who want to keep saying I was following too close. Thats easy to say sitting on your computer. I am telling you now, had I been in our Honda civic I would not have hit the car. The V slid horribly and was not controllable. This is a brand new car and it should handle better period. Is it the brakes themselves. or the tires, or some math crap? I don't know or care, I expect when I get a new car that the brakes should stop the car without a huge slide. I drove my wifes Honda on the same road after a rain, and tried recreating what happened. I went 70 instead of 60 and locked them up. The car stopped, imagine that, it was controllable and the ABS kept it from sliding. I will say once more, I have been driving over 20 years and this was my first wreck. I drive on the highway daily. I understand about being too close and I am telling you the car should have been able to stop before hitting the other vehicle. I just wasn't that close. If I keep the V I will have to try something different. I am thinking about putting on wider tires. Unfortunately that means new wheels also. This is going to be expensive, plus I am still stuck with the 1k deductible. I don't think someone should have to put money into a brand new car because the manufacturer cut corners. I got lucky I wan't seriously injured, I hope they fix it before someone is.

[versabundus]

There you are in fact wrong. I have had to "emergency brake" on many occassions. I autocross my versa, which I'm sure you are aware of the necessity for both brakes and tires. I did one session with the stock tires and immediately switched to a different set for autocross days (running 205/50 r 15 on 240sx alloys). I don't have a problem with unpredictable braking at the edge while I'm autocrossing. I do get the twitchy feeling while I'm running on my economy street tires(OE). I have done 2 events with the only changes being tires. The next one I will do with some other mods but that is neither here nor there. Again the fishtailing is due to the tires skidding, the versa loses all weight in the rear (which isn't much to begin with) under hard braking. This in turn unloads the rear of the vehicle making the tires ability to grip in the rear nearly non-existant. This weight transfer is what causes the rear end too lock up. Try emergency braking with 4 people in the car. I can almost gaurantee that the fishtailing will not be nearly as prominent or severe as with one person. I did experience this problem on my street tires until I got my eibach springs. The springs drastically reduced the dive under braking. The rear brakes are also adjustable but I don't advise doing it unless you know what you are doing. I will be messing with my brakes come next month's event if need be. I'm hoping I can get a tire off the ground around corners.

Disc brakes would reduce the amount of braking force in the rear but they would also wear faster and maintenance would be more costly. Also I think the economy difference between the stock tires and something a little bit better (not necessarily my azenis rt-615) would be minimal at best. I will, at my next fill up, will switch to my autocross tires and sport them for two or three tanks of gas and see if there is a difference in economy, but it's hard to compare apples to oranges. Especially with different rims and different tires sizes. But I will report my findings.

Been There: Going 48 mph on secondary road with 4 people in the car. Beautiful clear 60 Degrees. Small dog runs onto the road. Hit the brakes thinking No problem I can stop. Long fishtailing slide toward dog. Hit dog. I know that I could have easily avoided the dog with any of my other vehicles. BTW I have perfect depth perception.

[DocPlez]

Well Ahole isn’t as bad … I was shooting for arrogant pr!$k. Just kidding … I am sorry to hear about your accident and I’m glad you weren’t hurt bad but once again people seem to be missing the point completely. Your original post basically says your accident was entirely the cars fault and that simply isn’t true.

On 12/20/2006 you posted: “Had to lockem up going 60 on a wet road in my SL. It slid terribly as the non abs brakes sucked ***.”

So you knew the car had no ABS and wouldn’t stop like an ABS equipped car.

On 12/21/2006 you posted: “I was a good 3-4 car links back when I locked em up. You know you really can't go below 60 on the highway, wet roads or not fellas.”

You’re basically saying you had no choice but to go 60 and we should all understand … wet roads or not but the speed your car is traveling is your choice no matter what. I have no problem going as fast or as slow as I feel comfortable whether I’m being tailgated or not.

In the same post on 12/21/2006 you stated: “They sucked on dry pavement as well. I have had another near miss before this inciddent and I remember thinking oh sh*t, These brakes are the worst of any car I have ever driven.”

So you're driving a car that you know has no ABS and you’ve already had an incident to prove to you that the car may have braking issue. Yet you still chose to go 60 on wet roads and follow at 3 – 4 car links behind. Hmmm ... yep must be the car.

On 01/08/2007 you posted: “I don't think someone should have to put money into a brand new car because the manufacturer cut corners.”

Well … ABS isn’t standard equipment and Nissan advertised that so I fail to see how their decision not to use an available technology is cutting corners if they tell you the car isn’t equipped.

The statements others have made that “every other car I own would have been able to stop or avoid the accident” is great for them but it’s not true for everyone. The key is to know your car and drive to it’s limitations .. not to drive it like every other car you own.

I own 5 vehicles (well I sold my F350 yesterday so now I’m down to 4) and every single one of them stops, starts, brakes, turns, accelerates, etc., differently. They have horsepower ranges from 540 to 122, only 3 have ABS and one doesn’t even have seat belts (made it 1956). When I drive these vehicles I’m conscious of its capabilities and limitations and I drive accordingly. How many of these have I wrecked ... none ..... EVER!!!

I do have a question … did the police respond and if so where you cited and for what? I have no idea what state you live in but here in Nevada if you impact the rear of another vehicle it is your fault (good brakes, bad brakes, ABS, no ABS, etc) unless your were struck from behind and the impact pushes your vehicle into another vehicle or you have a mechanical failure (flat tire, etc).

Like I said I’m glad your all right but telling me this is completely your Versa's fault is like someone saying it’s the gun manufacturers fault when their crazy ex-girlfriend shoots them.

[versabundus]

What's there to hit in East Podunk? And what jroot is saying IS true. The brakes do suck. Consumer Reports states that the Versa's stopping distance is one of the longest in recent testing and still isn't good even with abs.

[DocPlez]

LOL .. all right you got me there ... most of the accidents that happen out here are SVRO (single vehicle roll overs) or car vs cow/wild horse (no one win's in that one). I don't personally brake or swerve for any animal my car or truck can run over ... I refuse to chance wrecking a car or killing myself to save the easter bunny because he's hanging out in the road.

My point exactly ... it's pretty much established the brakes aren't great ... so you realilze that and drive accordingly ... give more than 3 - 4 car lengths, slower on wet roads, etc. It's not an ABS equipped Honda, a stability control equipped BMW, or a wide track Dodge so you shouldn't drive it like anything other than what it is ... comparing the Versa braking to any ABS equipped car is apples to oranges.

[marleyfan]

I agree that it is fallacy to blame the car when you have the knowledge of the braking limitations and follow only 3-4 car lengths behind doing 60 on wet roads. They you say - my OTHER car would have stopped. Had to lock them up at 60 3-4 car lengths back on wet roads often? The fact is, if you have to lock them up then you are following too close. Also, not all wet conditions are equal. Sections of roadway can have oil or other lubricants or even rubber from tires which, when combined with rain, make them very slick. All I'm saying is, don't put the ENTIRE blame on the car. Accept SOME responsibility. Having said that, I also agree that Nissan should take another look at the braking system on the non ABS cars.

[versabundus]

Doc, I was in Arizona a few years back and it's like another planet to anyone who grew up in the East. It's beautiful though, and easy to roam through. Anyway, Marley, I don't lay blame squarely on the Versa. But I do think the brakes stink, and can't imagine why they would let it out of the box the way it is.

[proxim2020]

It keeps coming up that the brakes suck. But for the none ABS equipped cars, if the brakes have locked on all 4's, haven't they done their job? Haven't the brakes done all that they could do to slow you down? From this point on it wouldn't it be a design flaw in the car itself (weight distribution, crappy tires)?

[marleyfan]

With all the snow and ice we've been getting my ABS has activated a few times lately. Man it is the noisiest cheapest sounding ABS I have ever heard. And this morning I started to hear a "thunk" every time I take my foot off the brake. Time for a little visit to the service dept.

[versabundus]

It keeps coming up that the brakes suck. But for the none ABS equipped cars, if the brakes have locked on all 4's, haven't they done their job? Haven't the brakes done all that they could do to slow you down? From this point on it wouldn't it be a design flaw in the car itself (weight distribution, crappy tires)?

It's the stopping distance that sucks.

[proxim2020]

It's the stopping distance that sucks.

Better rubber would help out a bunch. Those Continentals aren't worth crap. If Nissan equipped the V's with better tires (maybe a better compound or wider tire), that would help a ton with road to tire friction. The only other thing I could think of would be to improve tire to ground contact. By keeping the back end down with really good road contact would help on the fishtail and give more balanced braking (well more like a more balanced skid). Stopping the nose dive effect will help keep that back end down.

[Ever Victorious]

Better quality tire would certainly help. I don't think that a wider tire might be prudent at least from the factory. Wide tires are great for performance in handling, acceleraton, and braking... but they are not good for fuel economy or snow performance.

[catnap]

I agree the tires are crappy. Sometimes they squeal and slide when starting from a stop and I do not pull away fast.Can somebody please recommend some good tires and the size to put on (without new wheels)? I live in the Bay Area so snow is not a problem.

[Ever Victorious]

Consult your local tire shop. Discount or Tirerack would be best.

Sometimes you can get an extra 10mm on the stock rims... so instead of a 185 width, you could theoretically get a 195.

[proxim2020]

I agree. Consulting a tire should would be best. As far as which makes are the best, that's a guessing game. Before when I owned a car, I also choose Michelin's. They handled great for the car and help up pretty well. I tried them on my truck and worn them out quickly and constantly had problems with road debris in the tire. I find that companies like Yokohoma and Kumho make pretty good tires no matter the application.

[Ever Victorious]

Some of the best OE-equivalent tires I have had were:

Michelin Energy, Ohtsu Zexius, Yokohama Avid

Some of the WORST OE-equivalent tires I have had were:

Toyo Ultra, Firestone (any), Continental, and Hankook.

I've also owned several sets of performance-grade tires... the best of those that I have owned were the Toyo Proxes 4. Go figure, toyo makes crappy (but long-lasting) OE tires, but good performance tires.

[catnap]

Thanks for the recommendations. For my old car -a Celica - I always went to WheelWorks since they are close and seemed to have good prices. Are they considered a good dealer?

[sunnyweathergirl]

I live in a wooded area of PA and see big deer everyday on the road. There's been numerous times when a deer runs right out in front of me and stopping my Versa has never been a problem. Maybe it's because before this car I had a 1986 Chevy S-10 which I had to pump the brakes and it took a lot longer to stop than this car.

Or maybe I know how to use brakes that aren't anti-lock.

Either way, if you can't drive a car without anti-lock brakes maybe you shouldn't drive a car to begin with.