I'm an amateur racer, and I can tell you that seat belts are only a small part of the equation that makes racing crashes survivable. Racing seats are built to fit individual drivers, for instance, and the cocoon -- the portion of the frame where the driver sits -- is designed to protect the seat.
Additionally, race cars are designed to essentially disintegrate in hard wrecks -- the cocoon stays intact, but the rest breaks away as a means of absorbing energy. Road cars have a similar design with crumple zones, but race cars take it many steps further.
It's also come to light in the last ~15 years that belts are simply not enough in some instances. Dale Earnhardt (possibly the most famous racer in history) died in an average-looking wreck at Daytona in 2001 because his neck snapped in a collision with the wall; drivers are now required to wear head and neck restraints to prevent this.
Track design plays a role as well. You've probably seen tire walls and gravel traps, but newer technologies -- like SAFER barriers (energy-absorbing walls made of steel and foam) -- have come along and are replacing the old guard.
There are certainly a lot of other things in racing that contribute to safety. But the biggie is always the harness.
A roll cage won't do jack for you if you're flying around in the cockpit smashing into the roll cage. Crumple zones are also ineffective if you're not strapped in.
Race cars don't have air bags. If you're strapped in tightly, the air bag adds nothing.
I've been in a crash where the belt saved my life, or at least prevented a crippling injury. I walked away with a broken nose. A roll cage or a HANS without belts would not have helped.
One of my cars has three point seat belts in front that do not spool. It is infuriating to unlatch the seat belt every time I have to back-up the car or reach for something on the passenger side. Racing harnesses are even more restrictive when adjusted properly.
The same racing drivers who have to wear top-line racing helmets connected to HANS devices, wear fire-resistant overalls, have medical teams on immediate standby, and who are often strapped in by their mechanics before heading off?
I think you may be overlooking an awful lot of what makes modern motor racing safer than it was in the past.
(and that's ignoring the number of serious injuries and driver deaths that still occur thanks to freak accidents)
I'm looking at the kind of accidents where an airbag is supposed to be effective. An airbag will do nothing for you if the car is burning.
The first and foremost safety device in a race car is the racing belt. The belt means you slow down with the car, which is much less deceleration than if your body hits the dashboard. (The point of crumple zones in the car is to reduced peak deceleration. In order for that to work, you gotta be strapped in.)
An airbag allows the driver's head to experience even lower deceleration than the car, because it gives the head an extra 1-2 feet in which to decelerate--the distance between the upright position and smashed into the deployed airbag.
When wearing a 5-point harness without a helmet and head restraint, the deceleration delta between the car and the head will be entirely borne by the structure of the neck, which is how Dale Earnhardt died.
The fire suit and undergarments are what keeps you alive long enough to be extracted in the event of a fire. They are literally rated in terms of how long they protect you commonly listed as the "Time to 2nd Degree Burn" specification which is arrived at by taking the TPP rating per the SFI spec and halving it.
Before the HANS device was used in NASCAR, I witnessed some serious wrecks during auto-racing that drivers got out of the car under their own power and were fine.
I wonder if the percentage of fatalities from wrecks in auto racing is better or worse that high speed accidents on public highways. It would be an interesting statistic to compare.
Nascar cars use roll cages, so as long as you are strapped into your seat safely you will survive most crashes, if the car doesn't catch fire. Most regular cars don't have roll cages.
> as long as you are strapped into your seat safely
That's the important part. Most of the safety devices in a nascar car (or any racing car really) only make sense if you're tightly strapped in the first place. So the first thing is seatbelt, always. Then you can add more stuff protecting the driver under the assumption that the driver's body will move with the car rather than independently within it.
The seat belts are the most effective. Helmets and HANS add to that, but the belts are the #1 safety device.
Another anecdote is in order. My father was a fighter jet instructor. The usual arrangement is tandem seating. He related an incident where the jet went off the runway, the nose gear sunk into the mud and the jet went up on its nose.
The guy in back had taken off his shoulder harness while taxiing, but left the helmet and lap belt on. He hit the dash so hard it left his brains splattered all over it, despite having a helmet.
The guy in front left his shoulder harness on, and was uninjured.
My father said that after seeing that, he never unbuckled the harness until the airplane was parked and the engines shut down. He also never moved his car an inch unless everyone in it was buckled up, and this was in the early 1960's long before it was fashionable. I picked up the habit from him :-)
I too think that being buckled-in is the most important, but a 4 or 5 point harness will just not work in a street car. Maybe my best advice is for you to read the relevant sections in the SCCA handbook. Forget about the cage, assume just a cross bar and harness. You will see that it makes it impossible to have the harness at a safe orientation for the driver yet allow a rear passenger. Also when you add the cross bar as it also required, it is now unsafe for a rear passenger.
Further any car with a cage has other compromises and some of those reasons for a cage are for things like being able to quickly jack the car up and rigidity (not just safety) but limits how people can enter and exit for example.
A harness is just not a good fit for a street car. The three point seat belt is an excellent compromise.
iirc, Volvo did a lot of testing to find the optimum setup in an ordinary passenger car. The 3-point belts worked best, as they were the easiest to get out of after an accident. Remember that race cars typically have people waiting in the event of an accident to assist in removing the person from the car. In a more typical accident, it can be much longer before help arrives. As a result, seat belt setups must be easy for the user to get out of by themselves. While 5-point systems fared better in the actual accidents, 3-point systems more than compensated by allowing individuals to free themselves from the car and preventing further injuries.
The 5 point racing harnesses have a very easy to use quick release on it, as it releases all the straps at once. You don't have to unthread your arm from it, like you do with a typical car 3 point system, and the release on typical auto belts is inferior. The webbing is narrower and thinner, too.
When I crew it takes a few minutes to adjust the seat and harness anytime we have a driver change. The genius of the modern three point seat belt is how easy it is to put on (comparable to lap belt, yet much more effective), how comfortable it is to wear (with the advent of the spool and height adjustment), and effective (due to seatbelt pretensioners).
5 point harnesses are completely impractical with many types and styles of clothing.
I don't know if you can legally install one to replace your 3 point by choice, but if you mandated them I suspect seat belt usage would plummet, which seems counterproductive.
For that matter, mandated helmet usage would improve many types of injuries, but I don't see that flying either.
From a public safety point of view, many of these decisions are more about balancing compliance and safety, rather than safety alone.
I've often wondered how many lives would be saved if people wore helmets during daily driving. I'd bet a lot. Of course, good luck getting people to do it.
I would not be surprised if helmet usage increased serious accidents/injuries and fatalities. The peripheral vision (for crossing roads, rotaries, and spotting pedestrians) is vastly worse wearing a helmet, at least the SA full-face helmets I've worn in amateur motorsports.
Race tracks don't have most of those hazards, and control most of the pedestrian hazards, with the limited pedestrians on the hot side of the pit wall assuming much of the responsibility for their own safety.
This would be offset by a reduction in head injuries (with a possible increase in neck and spinal injuries). I think I'd bet a full study would show an overall decrease in safety.
"vastly worse wearing a helmet, at least the SA full-face helmets"
Which is why the research into this topic focuses more on headbands, which mostly protect the forehead, than the entire head. See http://www.copenhagenize.com/2009/10/australian-helmet-scien... for a summary of Australian research and a sketch of the head gear. They quote:
> But more impressive were the estimates of introducing protective headwear for car occupants. The authors of the report estimated that the annual reduction in harm would be in the order of $380 million. The benefit of padding the head is that the head is protected from strikes with unpadded automotive components, exterior objects and in vehicles that predate any eventual introduction of padded interiors."
I actually wonder if there is a limit on the size of the A pillar in cars. The car I drive right now seems like it has a larger A pillar than the (super old) car I had before, presumably for safety. But it's almost caused me to get into several accidents as I am almost completely blind when slighting left. Just the other day I nearly hit a pedestrian who was crossing against the light. I slowed down for the turn but had the green light, and the pedestrian was crossing the street at just the right speed to stay in the blind spot of my driver's side A pillar. If I hadn't moved my head to double check, I would have run them over. I've never had this issue on any other car, but it's a big problem for me right now.
So imagine that blocking a good section of your forward vision, and a helmet blocking anything to the sides... motorcycles have very small blind spots as the rider can swivel anywhere with no cage blocking them. Helmets are a minor contributor. But cars don't have that luxury.
There are some horrific crashes in auto racing and the drivers walk away. That convinces me.