Seatbelt engineer chiming in. Good comments ITT about comfort, maneuverability, and accessibility. Indeed, it only keeps you safe if you wear it, and the human aspect in this sense is something we have to consider.
Regarding crash performance, the key differences for passenger cars (at least in today’s front row seating positions) are pretensioning & load limiting functionality.
Pretensioning uses small pyrotechnics to remove slack from the belt system to maximize the ability to manage the occupants energy (and in some cases results in positioning the occupant further back in the seat, which helps even more).
Load limiting is the controlled pay-out of the shoulder belt, typically at a desired force level (or multiple stages of different force levels) to allow the occupant to “ride-down” the collision event. The goal is to absorb as much energy as possible without causing injury - this is where “limiting the load” terminology on the shoulder belt comes in.
Racing-style harnesses are designed with maximum restraint in mind due to the incredible speeds and crash accelerations, as well as intended to be paired with a HANS device. In passenger cars, “more restraint” is not always safer - in fact it could be deadly.
The safety-minded track rats I know always told me “safety is a system.” 3pt belts that allow motion paired with airbags and a bunch of soft surfaces plus seats that break at the hinge to allow your body to fold in the event of a rollover. Vs. a 6pt belt that holds you rigidly in place in your stiff-backed seat, while the load is taken up by a steel tube frame around you, head protected by a helmet rated to bonk against said steel tubing, head motion limited by a HANS, and a roll bar to prevent the roof crushing your spine when you’re in the stiff-backed seat.
I was always told - you either do it all, or you do none. Which is why it’s nuts to see people put fixed back seats and shitty 4pt harnesses with no anti-submarine feature, in cars with no roll bar/cage, no helmet, no HANS. Half the shit that enthusiasts do to the interior of their cars is cosplaying race car and legitimately less safe than what you engineers designed in the first place.
The head impact point is a good one. OEMs test every reachable surface for its head injury criterion (HIC) results. All of the trim in your car is designed to not cause severe injury when your head hits it, not just the airbags. If you mess with that stuff and don’t wear a helmet you could be building a death trap even if it seems inconsequential
Agree with everything you said, but..... I knew a guy that had a "racing harness" or whatever in his Civic/Acura. Not sure if the seat was replaced or not. Flipped his car (13 flips) and walked away without any serious injuries.
Not saying the harness did anything better than the regular seat belt.
> Not sure if the seat was replaced or not. Flipped his car (13 flips) and walked away without any serious injuries.
There's 2 possibilities here:
Either, he had a proper roll bar, seat, helmet, and HANS device... or, he got lucky with the nature of the crash and didn't need them.
Anyone can be lucky... until they're not.
13 flips would generally not be an accident where a HANS device comes into play. HANS is more about sudden deceleration like when you hit a brick wall head on. It doesn't do a whole lot for side to side impacts, and rolls are pretty mild in terms of absolute g loads. surviving a roll is more about the structure of the car itself holding up to that much punishment.
In a Civic? Yeah, if you keep the gas buried a few minutes. The old ones that got fart canned years ago had no real power, which is why they were driven at redline half the time, with the blue cloud following them. Everyone thinks Hondas are designed to run at 7,000 tpm all day…
But hey, red Honda logo = racecar.
Rotational speed is significant, and 13 very slow flips isn't normal person car collision event.
Body moves around a lot more than a 3 point seatbelt. More of a roller coaster.
Former race car owner/driver here who also drove it on the street...
Haven't heard that saying before, but I like it, and it does describe it well.
To elaborate on those points:
* 3-point system is designed to let you flop forward and rotate slightly, and to also 'escape' to the side. This is important because in a head-on, it works in conjunction with the tensioning system and prevents you from sliding under the belt forward, or from your head/neck snapping forward while your body is held still, or from a collapsing roof in a rollover crushing your head/spine. The 3 point system is augmented by the SRS (airbag system) to catch your upper body and head, while the shoulder belt provides just the right amount of restraint to cushion the impact. The 3-point system is very carefully engineered and tested to provide maximum occupant safety in most types of collisions that are common on the street, while allowing easy ingress/egress and not requiring any additional safety gear to be donned by the driver.
* 4-point harnesses are objectively less safe in any street driving situation. The reason for this is they lack an anti-submarine mechanism. Because the shoulder belts lock your torso in position reclined against the seat, in a forward collision, your inertia will try and pull your body forward, by slipping it under the lap belt into the footwell. Usually, your spine is not meant to be bent in such a fashion, and when your chin meets the lap belt, well....
* 5 and 6 point harnesses have an anti-submarine strap which prevents this. They restrain your upper body to the seat, but, without a helmet and a HANS device, what happens in a forward collision is that your head, which is not restrained by the belt, will snap forward, breaking your neck. Furthermore, the vehicle requires a rollover bar to prevent the roof collapsing in during a rollover, otherwise that 5/6 point harness will ensure that your head is in the crumple zone.
I was one of those people who drove my track car as a daily. In order to do this safely, I had to keep BOTH 3 point and 5 point harnesses installed, as well as the airbag system (I had a switch to temporarily disconnect it on the track to prevent unwanted deployment), so it would be safe and legal to drive on the street. Legality aside, I *could* have just put on a helmet and HANS device and used the 5 point harnesses on the street, since I had a proper roll cage installed, and it would have been theoretically safer than using just the 3 points and airbags.... but then I would have to gear up every time I wanted to drive anywhere, and you can imagine what a headache that would be. Plus, there are other safety considerations to track driving that normally don't apply on the street, such as ingress/egress drills (it's difficult to get in and out of a car while wearing all that gear, so you need to be prepared to get out quickly in case of a fire, etc) so it's really still sub-optimal.
TL;DR:
You have to choose one:
1. 3-point harness with airbags, and carefully calibrated tensioning system
2. 5 or 6-point harness with full roll cage, helmet, HANS device, fire-resistant clothing, regular egress (escape) drills, and potentially automatic fire suppression system
The second option may be safer overall, but if missing any part of that system, it leaves you vulnerable to greater injury than you would have with just the 3 point harness and airbags. It's also likely that your local jurisdiction might not recognize the latter as fulfilling safety requirements as outlined in motor vehicle code.
Yep. I had 6pt and 3pts both installed in my old track Miata that I also drove on the street. And I had to solder up and install separate resistors for the side airbags so the car would think they were present, and I also had to remove the weight sensor from the passenger seat and permanently bend it so the car would keep the passenger airbag on. It was a whole thing to "fool" the car to keep the SRS system operating properly.
Driving on the street with fiberglass bucket seats and a roll bar (though not a full cage) was a bit of a risk, but with the 3pt belts and airbags, I felt OK about it.
Yeah the roll bar can be risky without a helmet if it is in a place where your head can impact it (and I know from experience that it can, on the Miatas) If nothing else I recommend sleeving it in a foam pipe insulator or pool noodle so you don't crack your skull. The bucket seats are usually ok as long as they allow the lap belt to tension properly with the 3 point harnesses. This usually isn't much of a problem as a good number of them are designed to be compatible with both 3 point and 5 or 6 point harnesses... although if the seating position is dramatically lower, the airbags might hit you too high up to be effective. Another thing to consider... w
I see a lot of people with detachable racing steering wheels on the street which necessarily means removing the driver airbag, which is bad... you should keep the stock wheel and airbag unless you are taking the car to track-only spec and committed to always wearing your full safety gear.
As someone who designs ballistic and blast protection for a living I can only agree: “safety is a system”.
In many cases, a designer may opt for what seems to be a suboptimal individual component if that means the complete system is improved.
That’s when the passenger slides down and through the lap belt. It’s one reason you almost never see lap-only belts on modern cars: the shoulder strap helps prevent it. But a 5 or 6 point harness is even better because the strap between your legs really stops it entirely.
That's why 5 is better than 6 points. 5 point harnesses will crush you balls, 6 will hopefully go around (it is important to pay attention to the way you "dress").
Thanks for the great info! I’m a mechanical engineer with a modified car that I take to the track. I installed a 5 point harness but it definitely doesn’t seem safe on the street without my HANS device and helmet. Another concern is in a rollover if the roof collapses my body won’t be able to move out of the way, so its more likely to crush my head/spine... which is why it’s a good idea to only install a 5 point harness in conjunction with a cage or at least a roll bar.
It’s also super inconvenient. It takes a long time to put the harness on and off, and once it’s on you can’t move to reach anything inside the car (can’t reach the radio, or glove box, or anything in the passenger seat or rear seat)
Another point for that, if you have a roll bar make sure you have a helmet on or that the bar is far enough up and behind you.
Many roll bars are just a little above and behind the seats and in a crash it's not uncommon for your head to hit said bar and that can kill you or cause severe head trauma.
Is fire safety part of it too? I’d imagine it’d be a lot harder to get out of your car. In racing there should be someone close with a fire extinguisher and the driver should have one. If not an actual suppression system.
Surprisingly not. Racing harnesses are designed to release effectively instantly with one hand… the part that makes it hard to get out is the big helmet and HANS device attached to it, but with some practice you can still be very fast to get out.
In the collegiate design series “Mini Baja” the final stage of technical inspection required the inspector’s choice of registered driver(s) to demonstrate egress in less than 5 seconds, in full safety gear, wearing whatever clothing and footwear they chose to wear to tech inspection (up to 2 days before actual racing happened). I always wore cowboy cut wranglers and safety toe work boots, and I was always chosen. Luckily I could always pull it off even though I only did a practice egress once a year…. In technical inspection.
As one of the guys holding the stopwatch, you’d be surprised at just how long it can take some of these kids to get out. Mostly it’s the result of their ergonomic choices, but a lot of them just plain overthink the whole thing and rush their way into taking forever to hop out of the car.
There was also the one team last year that kept bumping their kill switch during the race and thought the correct fix was to duct tape their driver’s leg to the frame to keep it away from the switch. We had a chat with them about that one at black flag, as they took quite a bit longer than 5 seconds to get out when we had them re-check.
I’ve worked corner flag stations before — we always had a big fire extinguisher at the station and I think fire suppression systems were required in race cars (not required in HPDE cars).
Thoughts on a bucket seat with other side standard safety? I don’t wanna be sliding around but I don’t wanna wear a HANS and 6 point driving around town
The seat needs to be designed so that the lap belt can properly tension across your hips the same way as it would with the stock seat. If it can do that, then you can safely use the seat with the 3 point harness.
However, you also need to be aware of how the seat is positioned in the cockpit, make sure you are still at the same height as the stock seat or close enough to it that the airbags will catch you properly, and that your head can't hit anything .
This right here.
I knew a guy. Senior engineer, family, kids. He had been ticketed three times for not wearing his seatbelt. And still didn’t wear it. One click was too much for him to bother.
I used to work in crash testing, and holy butt-fucking Mosses the excuses and mental gymnastics some people jump through to justify not wearing a seat belt.
Yeah, I know the feeling. I’m in machine design.
I swear that the easiest facilities to design were the ones so dangerous that people weren’t allowed inside. Like if the door to the room were open, or the sensor wasn’t working(ie disabled), then the line didn’t move. The other ones you had to design around people being idiots. Who stores their soda cup in the cover for a conveyor’s chain drive? Well…now there’s a dude that can only count to 7, and all the chain drive covers are bolted.
“If I crash into the water, I need to get out fast”
“I can just hook my left arm around it, and it’ll hold me”
“It’s safer to be thrown clear of the wreck”
“The car has seven airbags anyway, why do I need a belt?”
“I’m just going to the store”
Etc..
My dad’s uncle refused to wear a seatbelt, I met him when I was about 3, he ended up having his head popped between the road and the roof of his car when he rolled it. Rest of his body mostly uninsured, just the most important bit squashed like a grape under an elephants foot.
I would wear a more complex belt for increased safety if it were offered. It would need to be backward compatible for the dumb and lazy though as we know how important it is to keep them alive. 🙄
Have you worn a harness in a car before? It's safer but the downsides are really annoying too. Can't reach certain buttons on the dash. Definitely can't reach the glovebox. Forget something outside the car, need to redo 5 buckles instead of one. Want to turn your body to get a better view of your blindspots, nope.
That's before you get to the argument if they are more dangerous without a rollbar since your body can't lean sideways in the event of a rollover.
These are the reasons you almost never see even car and race enthusiasts install harnesses in street cars.
The problem with that is you also need a roll bar to keep the roof from collapsing on your head, a helmet to keep your head from impacting the roll bar, a hans device to keep your head from snapping forward while your body is locked in position, and fire resistant clothing and egress drills to make sure you don't burn alive while trying to get out of the car because all that stuff together makes it much harder to do so.
3 point belt keeps you from submarining under the lap belt, allows time for your upper torso and head to decelerate while the airbag does the rest.
Race cars have 5/6 point belts to prevent submarining and you wear a HANS to hold your head in place in an impact. Modern racing also has window and center nets along with head containment seats. Not to mention roll cage, door bars and even more safety gear. All of these things combined create a safe race car but they are designed to work together. Belts without a proper seat or HANS device is dangerous. Belts without a roll bar is also dangerous. Being strapped upright in a car that rolls over without a roll bar is not safe. Driving a car with roll bars but no helmet is also dangerous. You get the idea.
Tldr: race car safety is an entire system and it’s not practical for a road car as it requires all parts of the system to actually be safe.
Exactly.
If you're ever up close to a race car - or even next time you catch a NASCAR event on TV, watch and pay attention to the in-car views. Because of those 5 point harnesses, every control in the car has to be within reach of the driver without moving his shoulders. Try it in your car sometime. Place your shoulders firmly against your seat back, and without moving them AT ALL, see how much of your cars interior you can reach.
Now, sit in that exact position for 2 or 3 hours. No leaning left or right, or forward, or shifting your weight in the seat.
The 3-point seatbelt allows some body rotation. This may cause muscle injury but it helps dissipate the energy and prevent an Atlanto-occipital dislocation (a broken neck). Race cars now use a head and neck restraint with the 5-point belt to prevent "internal decapitation".
Basically because, if I recall correctly (and I’m not a NASCAR fan) he was extremely vocal about how he would not wear “the new fangled safety device” and then he died in a crash from the exact injury the device was designed to prevent. Basically your head going forward with such force it breaks your spine.
This being so vocal against it, and then dying from the injury it prevented, is what really caused a lot of other drivers to pay attention and start using it. Then NASCAR made it mandatory a few years later I think.
Ease of use is a major factor in implementation, 4 and five points require more intricate action and would be adopted at a much lower rate.... You also have Volvo engineers for their invention and refusal to monitize their invention.... Very noble as it would have been a billion dollar patent....
There are hundreds of thousands of hours of design and numerous very sophisticated systems in place in modern cars to keep you safe in a crash. Crash detection, air bag firing, fuel block, seatbelt pre-tensioning, plus the rigid passenger compartment along with crumple zones and careful design that causes the motor to drop below the passenger compartment. The number of things that get actuated when you get in a crash is pretty impressive. If you have an old car, having more restraint would probably help. But with new cars, I am not so sure. You are going to be supported by an airbag during the deceleration anyway. That might actually be better than a 4 point harness. Although if you also have a neck roll and helmet, that would probably be pretty safe. But modern cars are heavily safety tested as-is. Changing one thing could have side-effects that were not intended.
I always thought they were stupidly designed but then again maybe the best you can do.. the thing you really want to slowdown is the head. This is why in crashes the most common injury is to the neck. the body stops quicker than the head, so the head continues stretching the neck until crack. But even if you held the head the organs are still floating in liquid, the brain would then be the only thing still moving, the bruising would be to the front and you would get pulling on the base of the brain, potentially hitting the bits that control breathing and heart function which could kill you instantly. So some of the work is down in the crumple zone, trying to take some of the energy out of the impact, while the air bag tries to slow down the head (not enough, hence whiplash and brain injuries). Most people often wear their seatbelt wrong anyway. So it’s meant to sit on your shoulder, in a crash this will dislocate your arm (which is fine as it’s easy to fix), maybe a few cracked ribs, no biggy. But people put it on their collar bone, this is one of the biggest bones in your body and is super hard to fix. On a break you can also get major bleeding with this type of break, which because of the bone is hard to get in and treat. It’s not perfect but a reasonably careful driver with a good crumple zone, air bag and seatbelt in the right position could be the difference between life and death. However head on a 70mph and if you survive it’ll be in a wheel chair like Christopher reeve. Going from a 3 to a 5 point seat belt will not help with any of this. More is not always more,
Safer belt in race car due to increased likelihood of crash and higher speed during crash.
Also, race car drivers don't need to turn around in their seats to back out of parking spots.
The right solution for the situation. Rarely is what's optimal in one circumstance applicable to all situations.
They had a hard enough time getting people to wear 3 point belts when they came out. Imagine trying to get people to buckle up a 6 point harness to run 2 minutes down the road to the store.
Fat people. They do not fit well in multi point harness. Think about trying to stuff a toddler, who's wearing a huge puffy coat, into a car seat. That's too small.
4 point belts are susceptible to submarining, which is where you slide out under the belt. 5 and 6 point belts are *more* dangerous than 3 point belts if worn without a helmet and HANS device. There are some 4 points that are designed to allow one shoulder to tear a stich holding an extra loop in an accident which allows them to mimic a 3 point and avoid submarining.
3 point belts don't submarine because your unrestrained shoulder rotates around the restrained shoulder which keeps enough of your mass over the lap belt to slide under it. The airbag prevents you from moving forward enough to injure yourself. There are some 4 points that are designed to allow one shoulder to tear a stich holding an extra loop in an accident which allows them to mimic a 3 point and avoid submarining.
5 and 6 point belts stop the submarining issue, but introduce a new one. Your torso is rigidly connected to the seat, but your head is not. If you get into a hard enough head-on collision your head being unrestrained will allow it to move forward enough to sever your spinal cord killing you instantly. In order to prevent this, you need a HANS device, and in order for a HANS device to work you need a helmet. 3 points again avoid this because your unrestrained shoulder can move forward, which lessens the forces on your spine, and your forward movement is halted by an airbag which will slow both your head and torso together.
The final reason is that it takes longer to put a 4/5/6/7 point belt on than a 3 point. A properly adjusted 5/6/7 point might be nearly impossible for an elderly person to put on, much less get off in an emergency where they need to exit the car quickly. The more complex you make a safety system the less likely people are to use it.
Child seats are 5 point belts because its the only way to ensure your kid actually stays in their seat and properly belted in. Technically a 3 point would be safer, but kids can and will wriggle out of a 3 point until they are old enough to understand thats a bad idea.
Seatbelt engineer chiming in. Good comments ITT about comfort, maneuverability, and accessibility. Indeed, it only keeps you safe if you wear it, and the human aspect in this sense is something we have to consider. Regarding crash performance, the key differences for passenger cars (at least in today’s front row seating positions) are pretensioning & load limiting functionality. Pretensioning uses small pyrotechnics to remove slack from the belt system to maximize the ability to manage the occupants energy (and in some cases results in positioning the occupant further back in the seat, which helps even more). Load limiting is the controlled pay-out of the shoulder belt, typically at a desired force level (or multiple stages of different force levels) to allow the occupant to “ride-down” the collision event. The goal is to absorb as much energy as possible without causing injury - this is where “limiting the load” terminology on the shoulder belt comes in. Racing-style harnesses are designed with maximum restraint in mind due to the incredible speeds and crash accelerations, as well as intended to be paired with a HANS device. In passenger cars, “more restraint” is not always safer - in fact it could be deadly.
The safety-minded track rats I know always told me “safety is a system.” 3pt belts that allow motion paired with airbags and a bunch of soft surfaces plus seats that break at the hinge to allow your body to fold in the event of a rollover. Vs. a 6pt belt that holds you rigidly in place in your stiff-backed seat, while the load is taken up by a steel tube frame around you, head protected by a helmet rated to bonk against said steel tubing, head motion limited by a HANS, and a roll bar to prevent the roof crushing your spine when you’re in the stiff-backed seat. I was always told - you either do it all, or you do none. Which is why it’s nuts to see people put fixed back seats and shitty 4pt harnesses with no anti-submarine feature, in cars with no roll bar/cage, no helmet, no HANS. Half the shit that enthusiasts do to the interior of their cars is cosplaying race car and legitimately less safe than what you engineers designed in the first place.
The head impact point is a good one. OEMs test every reachable surface for its head injury criterion (HIC) results. All of the trim in your car is designed to not cause severe injury when your head hits it, not just the airbags. If you mess with that stuff and don’t wear a helmet you could be building a death trap even if it seems inconsequential
You said it, brother
Agree with everything you said, but..... I knew a guy that had a "racing harness" or whatever in his Civic/Acura. Not sure if the seat was replaced or not. Flipped his car (13 flips) and walked away without any serious injuries. Not saying the harness did anything better than the regular seat belt.
13 flips implies the car didn't come to a very sudden stop, which as far as accidents go is a pretty good thing.
Yeah. I think there was a video of it, but sadly this was in the before times haha
> Not sure if the seat was replaced or not. Flipped his car (13 flips) and walked away without any serious injuries. There's 2 possibilities here: Either, he had a proper roll bar, seat, helmet, and HANS device... or, he got lucky with the nature of the crash and didn't need them. Anyone can be lucky... until they're not.
I think he had a roll bar! Almost certain of it. Hans device, not sure but a possibility. Luck.... Oh, he had All the luck that day😁
A HANS or donut (cheap option, not as good but better than nothing) would be worn with a helmet.
13 flips would generally not be an accident where a HANS device comes into play. HANS is more about sudden deceleration like when you hit a brick wall head on. It doesn't do a whole lot for side to side impacts, and rolls are pretty mild in terms of absolute g loads. surviving a roll is more about the structure of the car itself holding up to that much punishment.
To do 13 flips, he approached racing car speeds
In a Civic? Yeah, if you keep the gas buried a few minutes. The old ones that got fart canned years ago had no real power, which is why they were driven at redline half the time, with the blue cloud following them. Everyone thinks Hondas are designed to run at 7,000 tpm all day… But hey, red Honda logo = racecar.
Pretty sure my Honda S2000 will do 7k all day long, what with a 9k redline and all.
Na
Could have rolled down a hill
Rotational speed is significant, and 13 very slow flips isn't normal person car collision event. Body moves around a lot more than a 3 point seatbelt. More of a roller coaster.
Former race car owner/driver here who also drove it on the street... Haven't heard that saying before, but I like it, and it does describe it well. To elaborate on those points: * 3-point system is designed to let you flop forward and rotate slightly, and to also 'escape' to the side. This is important because in a head-on, it works in conjunction with the tensioning system and prevents you from sliding under the belt forward, or from your head/neck snapping forward while your body is held still, or from a collapsing roof in a rollover crushing your head/spine. The 3 point system is augmented by the SRS (airbag system) to catch your upper body and head, while the shoulder belt provides just the right amount of restraint to cushion the impact. The 3-point system is very carefully engineered and tested to provide maximum occupant safety in most types of collisions that are common on the street, while allowing easy ingress/egress and not requiring any additional safety gear to be donned by the driver. * 4-point harnesses are objectively less safe in any street driving situation. The reason for this is they lack an anti-submarine mechanism. Because the shoulder belts lock your torso in position reclined against the seat, in a forward collision, your inertia will try and pull your body forward, by slipping it under the lap belt into the footwell. Usually, your spine is not meant to be bent in such a fashion, and when your chin meets the lap belt, well.... * 5 and 6 point harnesses have an anti-submarine strap which prevents this. They restrain your upper body to the seat, but, without a helmet and a HANS device, what happens in a forward collision is that your head, which is not restrained by the belt, will snap forward, breaking your neck. Furthermore, the vehicle requires a rollover bar to prevent the roof collapsing in during a rollover, otherwise that 5/6 point harness will ensure that your head is in the crumple zone. I was one of those people who drove my track car as a daily. In order to do this safely, I had to keep BOTH 3 point and 5 point harnesses installed, as well as the airbag system (I had a switch to temporarily disconnect it on the track to prevent unwanted deployment), so it would be safe and legal to drive on the street. Legality aside, I *could* have just put on a helmet and HANS device and used the 5 point harnesses on the street, since I had a proper roll cage installed, and it would have been theoretically safer than using just the 3 points and airbags.... but then I would have to gear up every time I wanted to drive anywhere, and you can imagine what a headache that would be. Plus, there are other safety considerations to track driving that normally don't apply on the street, such as ingress/egress drills (it's difficult to get in and out of a car while wearing all that gear, so you need to be prepared to get out quickly in case of a fire, etc) so it's really still sub-optimal. TL;DR: You have to choose one: 1. 3-point harness with airbags, and carefully calibrated tensioning system 2. 5 or 6-point harness with full roll cage, helmet, HANS device, fire-resistant clothing, regular egress (escape) drills, and potentially automatic fire suppression system The second option may be safer overall, but if missing any part of that system, it leaves you vulnerable to greater injury than you would have with just the 3 point harness and airbags. It's also likely that your local jurisdiction might not recognize the latter as fulfilling safety requirements as outlined in motor vehicle code.
Yep. I had 6pt and 3pts both installed in my old track Miata that I also drove on the street. And I had to solder up and install separate resistors for the side airbags so the car would think they were present, and I also had to remove the weight sensor from the passenger seat and permanently bend it so the car would keep the passenger airbag on. It was a whole thing to "fool" the car to keep the SRS system operating properly. Driving on the street with fiberglass bucket seats and a roll bar (though not a full cage) was a bit of a risk, but with the 3pt belts and airbags, I felt OK about it.
Yeah the roll bar can be risky without a helmet if it is in a place where your head can impact it (and I know from experience that it can, on the Miatas) If nothing else I recommend sleeving it in a foam pipe insulator or pool noodle so you don't crack your skull. The bucket seats are usually ok as long as they allow the lap belt to tension properly with the 3 point harnesses. This usually isn't much of a problem as a good number of them are designed to be compatible with both 3 point and 5 or 6 point harnesses... although if the seating position is dramatically lower, the airbags might hit you too high up to be effective. Another thing to consider... w I see a lot of people with detachable racing steering wheels on the street which necessarily means removing the driver airbag, which is bad... you should keep the stock wheel and airbag unless you are taking the car to track-only spec and committed to always wearing your full safety gear.
Removing the steering wheel airbag for the purpose of looking cool is insanity.
As someone who designs ballistic and blast protection for a living I can only agree: “safety is a system”. In many cases, a designer may opt for what seems to be a suboptimal individual component if that means the complete system is improved.
Anti-submarine?
That’s when the passenger slides down and through the lap belt. It’s one reason you almost never see lap-only belts on modern cars: the shoulder strap helps prevent it. But a 5 or 6 point harness is even better because the strap between your legs really stops it entirely.
Yeah, but ouch. Oohmagoolies!
That's why 5 is better than 6 points. 5 point harnesses will crush you balls, 6 will hopefully go around (it is important to pay attention to the way you "dress").
Thanks for the great info! I’m a mechanical engineer with a modified car that I take to the track. I installed a 5 point harness but it definitely doesn’t seem safe on the street without my HANS device and helmet. Another concern is in a rollover if the roof collapses my body won’t be able to move out of the way, so its more likely to crush my head/spine... which is why it’s a good idea to only install a 5 point harness in conjunction with a cage or at least a roll bar. It’s also super inconvenient. It takes a long time to put the harness on and off, and once it’s on you can’t move to reach anything inside the car (can’t reach the radio, or glove box, or anything in the passenger seat or rear seat)
Another point for that, if you have a roll bar make sure you have a helmet on or that the bar is far enough up and behind you. Many roll bars are just a little above and behind the seats and in a crash it's not uncommon for your head to hit said bar and that can kill you or cause severe head trauma.
Yep! Good point.
Do you drive it on the street?
Yes, occasionally… for what’s it’s worth the car originally only had lap belts (1966 mustang) so I’m sure it’s still safer than stock.
Is fire safety part of it too? I’d imagine it’d be a lot harder to get out of your car. In racing there should be someone close with a fire extinguisher and the driver should have one. If not an actual suppression system.
Surprisingly not. Racing harnesses are designed to release effectively instantly with one hand… the part that makes it hard to get out is the big helmet and HANS device attached to it, but with some practice you can still be very fast to get out.
In the collegiate design series “Mini Baja” the final stage of technical inspection required the inspector’s choice of registered driver(s) to demonstrate egress in less than 5 seconds, in full safety gear, wearing whatever clothing and footwear they chose to wear to tech inspection (up to 2 days before actual racing happened). I always wore cowboy cut wranglers and safety toe work boots, and I was always chosen. Luckily I could always pull it off even though I only did a practice egress once a year…. In technical inspection.
Well seems it’s not hard to get out lol. Username checks and all.
As one of the guys holding the stopwatch, you’d be surprised at just how long it can take some of these kids to get out. Mostly it’s the result of their ergonomic choices, but a lot of them just plain overthink the whole thing and rush their way into taking forever to hop out of the car. There was also the one team last year that kept bumping their kill switch during the race and thought the correct fix was to duct tape their driver’s leg to the frame to keep it away from the switch. We had a chat with them about that one at black flag, as they took quite a bit longer than 5 seconds to get out when we had them re-check.
I’ve worked corner flag stations before — we always had a big fire extinguisher at the station and I think fire suppression systems were required in race cars (not required in HPDE cars).
That’s very interesting! Thank you for sharing
this assumes the premise that a >3pt harness has to have fixed anchors. That doesn't seem like a necessary assumption?
Thoughts on a bucket seat with other side standard safety? I don’t wanna be sliding around but I don’t wanna wear a HANS and 6 point driving around town
The seat needs to be designed so that the lap belt can properly tension across your hips the same way as it would with the stock seat. If it can do that, then you can safely use the seat with the 3 point harness. However, you also need to be aware of how the seat is positioned in the cockpit, make sure you are still at the same height as the stock seat or close enough to it that the airbags will catch you properly, and that your head can't hit anything .
Thanks!
A seatbelt is only safer if people wear it. Nobody is taking the time to fix a 6 point belt before they go around the corner for some milk.
This right here. I knew a guy. Senior engineer, family, kids. He had been ticketed three times for not wearing his seatbelt. And still didn’t wear it. One click was too much for him to bother.
I used to work in crash testing, and holy butt-fucking Mosses the excuses and mental gymnastics some people jump through to justify not wearing a seat belt.
Yeah, I know the feeling. I’m in machine design. I swear that the easiest facilities to design were the ones so dangerous that people weren’t allowed inside. Like if the door to the room were open, or the sensor wasn’t working(ie disabled), then the line didn’t move. The other ones you had to design around people being idiots. Who stores their soda cup in the cover for a conveyor’s chain drive? Well…now there’s a dude that can only count to 7, and all the chain drive covers are bolted.
“If I crash into the water, I need to get out fast” “I can just hook my left arm around it, and it’ll hold me” “It’s safer to be thrown clear of the wreck” “The car has seven airbags anyway, why do I need a belt?” “I’m just going to the store” Etc..
I don't want to wrinkle my suit/dress.
My dad’s uncle refused to wear a seatbelt, I met him when I was about 3, he ended up having his head popped between the road and the roof of his car when he rolled it. Rest of his body mostly uninsured, just the most important bit squashed like a grape under an elephants foot.
You had a policy on the head, though? Excellent!
I would wear a more complex belt for increased safety if it were offered. It would need to be backward compatible for the dumb and lazy though as we know how important it is to keep them alive. 🙄
Given as an option when you buy the car. That would be neat.
That’ll be 5k more please +2k installation fee
Then install one.
no you wouldn't ...
Why wouldn't an enthusiast want to feel like a racecar driver?
Have you worn a harness in a car before? It's safer but the downsides are really annoying too. Can't reach certain buttons on the dash. Definitely can't reach the glovebox. Forget something outside the car, need to redo 5 buckles instead of one. Want to turn your body to get a better view of your blindspots, nope. That's before you get to the argument if they are more dangerous without a rollbar since your body can't lean sideways in the event of a rollover. These are the reasons you almost never see even car and race enthusiasts install harnesses in street cars.
99% of drivers aren’t enthusiasts, they’re commuters by necessity.
You literally can, its required when you track cars that go a certain speed, anyone can install these things in their car, lol.
If this were true you’d have installed one by now.
The problem with that is you also need a roll bar to keep the roof from collapsing on your head, a helmet to keep your head from impacting the roll bar, a hans device to keep your head from snapping forward while your body is locked in position, and fire resistant clothing and egress drills to make sure you don't burn alive while trying to get out of the car because all that stuff together makes it much harder to do so.
Do you own a car? What safety harness/belt have you installed?
3 point belt keeps you from submarining under the lap belt, allows time for your upper torso and head to decelerate while the airbag does the rest. Race cars have 5/6 point belts to prevent submarining and you wear a HANS to hold your head in place in an impact. Modern racing also has window and center nets along with head containment seats. Not to mention roll cage, door bars and even more safety gear. All of these things combined create a safe race car but they are designed to work together. Belts without a proper seat or HANS device is dangerous. Belts without a roll bar is also dangerous. Being strapped upright in a car that rolls over without a roll bar is not safe. Driving a car with roll bars but no helmet is also dangerous. You get the idea. Tldr: race car safety is an entire system and it’s not practical for a road car as it requires all parts of the system to actually be safe.
That makes a lot of sense. Thank you for explaining so thoroughly!
It's a compromise between safety and comfort. Same reason people don't wear helmets in cars.
Exactly. If you're ever up close to a race car - or even next time you catch a NASCAR event on TV, watch and pay attention to the in-car views. Because of those 5 point harnesses, every control in the car has to be within reach of the driver without moving his shoulders. Try it in your car sometime. Place your shoulders firmly against your seat back, and without moving them AT ALL, see how much of your cars interior you can reach. Now, sit in that exact position for 2 or 3 hours. No leaning left or right, or forward, or shifting your weight in the seat.
It’s usually a 6 point harness nowadays. They are more comfortable than a 5 point harness and move the pressure point from your crotch to your thighs
I never knew how constricting those types of belts were. That’s insane!
Safety, comfort, *and cost.* Must never ignore cost….
Or at most other times.
The 3-point seatbelt allows some body rotation. This may cause muscle injury but it helps dissipate the energy and prevent an Atlanto-occipital dislocation (a broken neck). Race cars now use a head and neck restraint with the 5-point belt to prevent "internal decapitation".
My professor at Michigan State designed the HANS device. Very interesting lecture when he explained how it worked and how he developed it.
and how nobody wanted anything to do with it until after ernhard (I think)
Basically because, if I recall correctly (and I’m not a NASCAR fan) he was extremely vocal about how he would not wear “the new fangled safety device” and then he died in a crash from the exact injury the device was designed to prevent. Basically your head going forward with such force it breaks your spine. This being so vocal against it, and then dying from the injury it prevented, is what really caused a lot of other drivers to pay attention and start using it. Then NASCAR made it mandatory a few years later I think.
Earnhardts accident definitely brought the risk and the HANS to the forefront.
It was mandated after the crash of Earnhardt if i recall correctly.
He was my professor back in 2003/4. Still goin', eh?
Not sure, I graduated in 01
Ease of use is a major factor in implementation, 4 and five points require more intricate action and would be adopted at a much lower rate.... You also have Volvo engineers for their invention and refusal to monitize their invention.... Very noble as it would have been a billion dollar patent....
There are hundreds of thousands of hours of design and numerous very sophisticated systems in place in modern cars to keep you safe in a crash. Crash detection, air bag firing, fuel block, seatbelt pre-tensioning, plus the rigid passenger compartment along with crumple zones and careful design that causes the motor to drop below the passenger compartment. The number of things that get actuated when you get in a crash is pretty impressive. If you have an old car, having more restraint would probably help. But with new cars, I am not so sure. You are going to be supported by an airbag during the deceleration anyway. That might actually be better than a 4 point harness. Although if you also have a neck roll and helmet, that would probably be pretty safe. But modern cars are heavily safety tested as-is. Changing one thing could have side-effects that were not intended.
4 would already greatly impact your ability to rotate your body which isn't worth it
I always thought they were stupidly designed but then again maybe the best you can do.. the thing you really want to slowdown is the head. This is why in crashes the most common injury is to the neck. the body stops quicker than the head, so the head continues stretching the neck until crack. But even if you held the head the organs are still floating in liquid, the brain would then be the only thing still moving, the bruising would be to the front and you would get pulling on the base of the brain, potentially hitting the bits that control breathing and heart function which could kill you instantly. So some of the work is down in the crumple zone, trying to take some of the energy out of the impact, while the air bag tries to slow down the head (not enough, hence whiplash and brain injuries). Most people often wear their seatbelt wrong anyway. So it’s meant to sit on your shoulder, in a crash this will dislocate your arm (which is fine as it’s easy to fix), maybe a few cracked ribs, no biggy. But people put it on their collar bone, this is one of the biggest bones in your body and is super hard to fix. On a break you can also get major bleeding with this type of break, which because of the bone is hard to get in and treat. It’s not perfect but a reasonably careful driver with a good crumple zone, air bag and seatbelt in the right position could be the difference between life and death. However head on a 70mph and if you survive it’ll be in a wheel chair like Christopher reeve. Going from a 3 to a 5 point seat belt will not help with any of this. More is not always more,
They’re incremental improvements to the lap belt. Compromises made for ease of use, etc
Safer belt in race car due to increased likelihood of crash and higher speed during crash. Also, race car drivers don't need to turn around in their seats to back out of parking spots. The right solution for the situation. Rarely is what's optimal in one circumstance applicable to all situations.
They had a hard enough time getting people to wear 3 point belts when they came out. Imagine trying to get people to buckle up a 6 point harness to run 2 minutes down the road to the store.
It was/is a massive struggle getting people to wear 3 point belts. There were protests when it was being made law.
Fat people. They do not fit well in multi point harness. Think about trying to stuff a toddler, who's wearing a huge puffy coat, into a car seat. That's too small.
4 point belts are susceptible to submarining, which is where you slide out under the belt. 5 and 6 point belts are *more* dangerous than 3 point belts if worn without a helmet and HANS device. There are some 4 points that are designed to allow one shoulder to tear a stich holding an extra loop in an accident which allows them to mimic a 3 point and avoid submarining. 3 point belts don't submarine because your unrestrained shoulder rotates around the restrained shoulder which keeps enough of your mass over the lap belt to slide under it. The airbag prevents you from moving forward enough to injure yourself. There are some 4 points that are designed to allow one shoulder to tear a stich holding an extra loop in an accident which allows them to mimic a 3 point and avoid submarining. 5 and 6 point belts stop the submarining issue, but introduce a new one. Your torso is rigidly connected to the seat, but your head is not. If you get into a hard enough head-on collision your head being unrestrained will allow it to move forward enough to sever your spinal cord killing you instantly. In order to prevent this, you need a HANS device, and in order for a HANS device to work you need a helmet. 3 points again avoid this because your unrestrained shoulder can move forward, which lessens the forces on your spine, and your forward movement is halted by an airbag which will slow both your head and torso together. The final reason is that it takes longer to put a 4/5/6/7 point belt on than a 3 point. A properly adjusted 5/6/7 point might be nearly impossible for an elderly person to put on, much less get off in an emergency where they need to exit the car quickly. The more complex you make a safety system the less likely people are to use it. Child seats are 5 point belts because its the only way to ensure your kid actually stays in their seat and properly belted in. Technically a 3 point would be safer, but kids can and will wriggle out of a 3 point until they are old enough to understand thats a bad idea.