roll cage in a car - why not?

Factual Questions
1

So is having an exposed roll cage in a car really all that bad? They’ve proven to be life savers in race cars, so why not use them in regular passenger cars? My first guess would be, they’re just too damn ugly. But, are they really?

I think they look alright, and I wouldn’t mind purchasing a car that had one. Okay, maybe they’d look a little weird in sedans, but in sports cars, they’d definitely have a place. So, why not? Is there a functional reason why car manufacturers don’t include them?

We’ve all seen the videos of race cars slamming into walls at 150MPH, then flipping over about 10 times, and after all that, the driver is able to walk away from it. Can’t that be attributed to the fact that the roll bars were there?

Now, granted, there are other safety measures in place, like a helmet, and not to mention seat belts that hold practically every part of the body down, but I’m willing to say that the main reason is because of the roll cage.

So, why not apply the same safety practices that NASCAR, the NHRA, the NIRA, etc. use, with regard to the roll cage, in street cars?

2

Some sports cars have shipped with roll bars. IIRC, Most Shelby Mustang models shipped with roll bars. Jeeps and some current convertibles have roll bars. But the roll bars take a lot of space and intrude into the passenger compartment. It makes it uncomfortable for the passengers.

3

To some extent, they do include them. Modern unbody cars have a reinforced cage around the passenger compartment, with crumple zones front and rear to absorb impact. I have heard of a few examples of cars that were totalled in accidents where the front and/or rear ends were crushed, yet the doors still opened normally. The passenger area was still intact.

A full-sized, traditional roll bar might be a problem without helmets and five-point harnesses, as people would hit their heads in minor accidents or during rough driving. Even in race cars, they recommend several inches of space between the harnessed driver and any part of the roll cage (IIRC, the spine can extend three to five inches during an impact.)

4

cornflakes has it right. As to why not include additional stiffening or an extra bit of roll cage, well, the real driver is cost. Plain and simple.

5

You can have a roll cage added to your car if you want. Just find someone in the phone book who does that sort of work. I think they weigh a bit too much & thus are not practical.

6

I agree with the person who said that cars already have roll cages of sorts.

I believe that you can buy racing type roll cages that will fit into a “stock” car. One problem is that a good cage will intrude into the rear seating area, possibly making it uncomfortable, or even unusable.

Possibly, a cage would also make it harder to get in and out of the car, since there may be a metal bar you’ll have to step over.

I think that part of what’s at work here is consumer preference. People are unwilling to pay a little more for a car that is safer and less convenient to use. In fact, in the United States, I believe that many safety features in cars are installed as a result of government mandates as opposed to consumer demand.

7
      • The problem with the factory including an actual “roll bar” as standard equipment is that idiot drivers can then sue if they roll and get hurt at all, because the roll bar didn’t give “sufficient protection”. This is why factory pickup trucks have “light bars” instead of actual roll bars. The cost of the roll bar itself is a consideration after the fact; from a litigation standpoint, it’s safer for the manufacturer not to claim any safety benefits at all. - MC
8

Inconvenience for the user, possible injuries by people not wearing helmets, and post-crash lititgation have been covered. But how often really do cars roll over? Sometimes. Sometimes they go over an embankment, too. But the majority of crashes aren’t roll-overs. I think their utility is outweighed by their monetary and non-monetary costs.

9

Well, thanks for the invitation to fly off on a tangent. :rolleyes: I’ve wondered about this for a while (and should have spent more time condensing this. Sorry.)

Passenger cars use different safety equipment, in part, because most people would hate wearing a helmet, fire suit and 5-point harness. Perhaps another reason the equipment is different is because the accidents are different.

Street cars are t-boned, run head-on into each other and fly off the road. Usually, the front corners, rear or sides are hit and the way that they are hit can be predicted and modeled. On the track, everyone at least starts out going in the same direction, and if there’s an accident, everyone is ready. Once the cars do hit each other, they tend to be spinning, and there’s no way to predict which side will be hit. Furthermore, the rules at local tracks generally allow for some variation in design (and of course, racers never bend the rules to their advantage.) In any case, T-bones are rare, and head-ons are nearly nonexistent (and yes, the concrete walls are hard, but are rarely run into head-on.)

Now, this is just a WAG, but I think that I’d rather have a lap and shoulder belt hold me not-too-tightly (relatively) in an anti-submarine design seat while I run into an airbag than be held tightly in a hard aluminum seat as my helmeted head hyperextends my neck, BUT I would rather be strapped in tightly if I had no idea which side of my spinning car was going to hit the wall or a car I was just racing.

Anyone care to comment? Did anyone read this?

10

The earlier, unsafe cars with no safety items, like in the 50s, could tumble down a hill and arrive at the bottom, battered but with the roof intact. It was not the same for the passengers, who either got tossed out of the windows or turned into very ‘soft’ people when most of their bones broke while being tumbled around the inside.

Newer cars, mainly ‘economy’ ones do not have strong roofs. Car builders figure that unless you are willing to buy the top of the line, you can make due with ‘crush zones’ that might distort the frame enough to keep the roof from turning you into hamburger. It would not be too hard for them to stiffen the roof supports, but even though they make major profits each year, they keep cutting corners and crying poor mouth.

I figure that ‘crush zones’ are the new way for saying ‘we took out the reinforcements to save money and to guarantee if you wreck you will do the maximum amount of damage possible at the least possible speed so you will have to get a whole new car or tremendously expensive repairs with our ‘genuine’ parts which are no different from the ‘cheap’ parts but we made a deal with insurance companies to say they were.’ (Whew!)

If you happen to get injured or dead in the wreck, well, they’re sorry but blame the high union wages and expensive safety standards and pollution requirements for us economizing.

They won’t mention that they are unwilling to drop the yearly profit picture one thin dime to save more lives.

11

cornflakes – nothing to add. Total agreement. (One small extra point, slight hijack – professionals, at least, now use a strap or other device to hold the helmet in place to avoid hyperextension of the neck; the main problem now is that the head doesn’t move, but the brain DOES, causing parts to come unsnapped – believed to be the cause of death for two NASCAR drivers this season. End of hijack.)

12

Just stumbled across this:

Crumple zones in action.

FWIW, here’s an example of a racing roll cage (I know that most don’t need an example, but just in case…)

13

Drahcir, if car companies didn’t profit from making cars, why would they actually do it? How high do you think their profits are anyways? Looking at Yahoo’s financial profiles, it says that DialmerChrysler has a profit margin of 3%, Ford is up there at 3.6%, while GM splits the difference at 3.2%.

So, yeah, cars could be made a little safer if the car companies didn’t bother to make money off of the deal. But I doubt it really do all that much. Especially if they are as dependant on using inferior parts as you claim.

14

Think of crumple zones like this: there’s a lot of energy that needs to be absorbed in a crash. That energy can be absorbed by a crumple zone, or by your body. Your choice.

15

Well, when Daimler Chrysler is earning $151 billion, a 3% margin turns a cool $4.5 billion in profit. I’m not exactly worried about them going out of business. (Click here to see DC’s 1999 annual report in pdf format.)

Drahcir is right, the car companies are willing cut all sorts of corners. When you are moving many millions of cars a year, shaving a nickel here and there in parts really adds up. I think our cars are pretty safe however, so I don’t have any major gripes.

16

I was certainly not trying to imply that the car companies are on the verge of going broke or anything, just that they’re not marketing vastly substandard cars in order to make out like bandits. I don’t think 3-4% is an unreasonable percentage. Especially when you consider that years with a net loss are not unheard of.

17

Many cars have been designed around a roll cage with Saabs and Saturns coming to mind. My Four-runner had an external roll cage behind the back seats and my Land Cruiser had an external cage as well. This was due to the fact that both could be made into convertibles and because they could and were used in an off road capacity where a rollover was more likely. In most cases an external roll cage would be more of a hazard to passengers than of benefit.

Cars of today are safer than ever, just because they are designed to absorb impact energies doesn’t mean that they are poorly constructed. Our 91 Dodge Spirit was hit by a 3/4 ton truck doing 50 mph in an intersection. The front end of the car was mush but the passenger compartment containing my then pregnant wife was completely intact. She broke her ankle on the brake pedal. The car did what it was supposed to do. I can always buy another car… Lola and my daughter are irreplaceable.

18

A lot about modern cars being safe is true. I flipped a Cadallac El Dorado end-over-end, twice, and came to rest upside down on the roof, the roof supported the entire weight of the car and I was able to crawl out through the drivers window. I went from 100+ mph to 0 in about 100yds and walked away with only minor scratches from broken glass. Seatbelts, airbags, crumple zones, and structural reinforcement all helped save my life. I won’t even go into the GOD factor because believe me, if you had seen the accident site and the car, there’s no way I should be here right now.

19

The top of the line cars are safer than the less expensive ones. The metal in most cars is thinner than ever before, the chassis is gone, strong bumpers are a thing of the past, passenger car side door reinforcements are gone, and many exterior body parts are fiberglass or plastic.

All designed to trim weight for better gas mileage, I know, but I’ve never seen cars crumple up as badly as those do within the past twenty years than the ones we have now. Yes, I know people survive more, but we have airbags, padded dashes, collapsible steering columns, better seat belts, crash glass, and the cars themselves are lighter.

I’ve watched the crash tests on economy to medium priced cars and noticed that the economy car ‘crush zone’ extends far into the drivers compartment and almost as much on the medium one. Roofs crush flat in roll overs far too often for my taste. On the road I’ve seen small fender benders at 5 mph rip up the front end of cars as if dynamight went off under the hood!

The car I owned in the early 70s hit the back of a truck doing 5 mph and only dented the front chrome bumper a bit, and did no damage at all to the truck. I owned a 1978 Impala and when it was parked, a driver careened off of the highway at 30 mph, hit the thing in the rear left corner, pushed it through a phone booth and over a curb. The rear end was lifted high from the impact and the corner was crumpled, but the thing was drivable! No damage to the passenger compartment, a dent on the front from mowing down the booth, and the car started right up.

The other car, a current one for the year, was almost totaled. The Impala had a heavy chassis and heavy bumpers mounted to it. Most cars do not have a chassis anymore. I was hit in a small car, in 1990, and I don’t recall the type, but it was a 1989 compact. Even though I steered out of the way of the approaching car and was still moving when he rammed me at 90 degrees in the front, the impact rendered my car unusable. The right front was hit and flattened, the wheel there exploded, the passenger door buckled, the front brakes went out but the rear one’s held, and the engine compartment distorted.

He was doing about 10 mph as he pulled out of a side road. I was doing about 45, but braked and moved off at a 45 degree angle to keep from T-boning him. None of us were hurt, but my engine failed and would not restart and the damage was around $4,000. Had he hit me in the side, the car would have buckled. His car, a current medium sized Ford, had the front end smashed into the engine, the hood sprung, and was undrivable. In my opinion, the amount of damage received by both cars was far too much for the type of impact.

I’m inclined to think that crush zones are an expensive alternative to other forms of safety. There used to be shock absorbing bumpers which did the same but they stopped making them. With crush zones, the repair industry is having a booming business.

I was rammed by an illegal passer when I owned a 1964 Ford Falcon (no jokes please) and all it did was dent the fender and bend the bumper. I hammered the bumper out and slapped on Bondo and my father took the bumper off and hammered it back into shape with a sledge hammer.

Same impact today in a similar sized car would require a couple of thousand in repairs.

20

Why do you(drahcir) hate modern cars so much? Becuase you dont have to adjust the points on them every 6 months? Becuase they get more than 12 mpg? Becuase they have cd players FM radio and cold A/C? Comfortable seats and batteries that last 6 years? Not to mention tires that are 10 times better than they were just 20 years ago. Or all the “little” conviences the modern car has. Power mirrors, windows, locks, BRAKES and STEERING. Remote keyless entry and accurate gauges are pretty nice too. All this and better for the enviroment too. And yet we still have people who miss there dads '56 Pontiac with the cool dashboard you could put magnets on. Or your head. And couldnt stop or turn all that well. Aaaahhh, but that car could go through grade school. Sure I like to see the old cars on the road and they made some really nice cars back in the day. For the time. By todays standards they suck. If you want a huge unsafe vehicle, buy an SUV.