Roll Over Protection discussion

[Mr Morlock]

My understanding is that Mazda still offer no roll bar for the MX5- refer brochures etc that list safety features.

The roll bar makers may test their bars but do they do any in car testing for the bars effficacy in road crash situations.

Ample padding on a roll bar?- try getting hit at 70kmh- even boxers can suffer brain damage with padded head gear and a boxing glove is padded but as we all know it can be very damaging.

The safety of the MX5 rates 5 stars (98-05) for used car safety ratings in How safe is your car. The MUARC site has a lot of dense data ( where is Guran to sort it out) )

[deviant]

My understanding is that Mazda still offer no roll bar for the MX5- refer brochures etc that list safety features.

The roll bar makers may test their bars but do they do any in car testing for the bars effficacy in road crash situations.

Ample padding on a roll bar?- try getting hit at 70kmh- even boxers can suffer brain damage with padded head gear and a boxing glove is padded but as we all know it can be very damaging.

The safety of the MX5 rates 5 stars (98-05) for used car safety ratings in How safe is your car. The MUARC site has a lot of dense data ( where is Guran to sort it out) )

As a modern car the roll over protection is going to be built in to the car. The windscreen surround would be strong enough to support the car and I believe the 2 silver hoops behind the headrests are not just for show. If it is anything like other modern convertibles those hoops will have an explosive charge underneath them (like an airbag) that will make the hoops pop up if the car tilts more than XX degrees. In the NC you also sit much much lower in the car.

The FIA fit cages to cars and crash them in the same lab environment that road crashes are done in...just at a higher speed. They even crash test F1 cars.

Are you sure the MX5 rates that high? http://www.howsafeisyourcar.com.au/_scr ... php?IID=99

Read the details carefully, the passenger compartment did not do well at all with serious risk of injury to the occupants despite it's 4 star rating.

Do not rely on the star rating alone, up to 2 stars can be awarded just for fitting an electronic stability program and 1 star can be awarded for fitting a seat belt warning light so that makes 3 stars even if the car folds up in a crash.

Yep the padding is not going to suddenly make something safer but it is better than no padding at all and is certainly safer than the hinge mechanism and the lovely half inch long nub that points at your temple a mere few inches from your head with the roof up.

It is worth nothing that FIA spec padding is not just pulmbers pipe lagging as I have heard some people say in the past. It is designed for the job it does and as with everything FIA is tested.

[Guran]

You rang?

Check this thread for previous discussion for the MUARC assessment of crash statistics for MX-5s. In summary, the NB was rated five stars and was one of the safest used cars available in Australia. The NA, on the other hand only scored the equivalent of two stars, although that was about average for "light cars" of the era. With the introduction of mandatory ABS, airbags, etc and consumer interest in high ratings for NCAP testing, light cars are now much safer (including the NB and NC).

It's worth noting that independent rollover testing of new cars in NCAP testing is NOT done in Australia, Japan or Europe. As far as I'm aware, it is only done by the US National Highway Traffic Safety Administration (NHTSA). They conduct static and dynamic tests of rollover risk. Why? Because high-riding SUVs and pick-ups dominate the US car market and used to be highly prone to rollover crashes. Incidentally, the NB and NC achieved the lowest rollover risk rating of all cars tested (7%), due to it's wide track and low centre-of-gravity.

With regard to rollbars used on the track, Schedule J of the CAMS Manual includes the following requirement:

"In open cars the roll bar must be a minimum of 50mm above the top of the driver’s helmet"

The BD rollbar only just fits in under the soft-top (mine touches the cross-brace or hardtop) and yet the top of my helmet is roughly level with the top of the rollbar. That is with a very thin raceseat on stock rails and I'm "height challenged" at only 5'6". Consequently, just about every NA/NB driver with a BD rollbar was severely chipped by one meticulous scrutineer at the Eastern Creek Supersprint on Saturday. However, Schedule J is clearly targetted at logbooked cars, and the scrutineer was not aware that special dispensation has previously been given to allow BD rollbars at Supersprints. Afterall, rollbars are not mandatory in road-registered cars used on the track, and some rollover protection is obviously better than none at all.

[deviant]

I'm genuinely interested in this subject....

So with the MUARC report how do they adjust the figures for the final numbers?

Say if 100 cars crashed with enough damage to render the car undrivable (it busted the radiator) but at a low enough speed that nobody was injured would it be considered that that make / model of car is '100% safe' as 100% of the people involved walked away even if a crash going 20KMH faster would cause serious injury or a fatality?

[bigdog]

Ample padding on a roll bar?- try getting hit at 70kmh- even boxers can suffer brain damage with padded head gear and a boxing glove is padded but as we all know it can be very damaging.

Well, I was hit at least at 60kmh (possibly more) in the rear. My wife suffered soft tissue damage from whiplash as she had turned in her seat to see what was making the approaching tyre squeal noise - her head was thus between the seats where the cross brace is. Neither of us contacted the roll bar, which by the way is covered in FIA spec roll bar foam. Sit belted into an NB with a BD or MX5+ bar and try and make your body touch the bar - it's not easy.

[Guran]

I'm genuinely interested in this subject....

So with the MUARC report how do they adjust the figures for the final numbers?

Say if 100 cars crashed with enough damage to render the car undrivable (it busted the radiator) but at a low enough speed that nobody was injured would it be considered that that make / model of car is '100% safe' as 100% of the people involved walked away even if a crash going 20KMH faster would cause serious injury or a fatality?

No, that's not how it works. The MUARC analysis normalises for a wide variety of complicating factors such as the speedzone in which the crash occurred (<75km/hr, >80km/hr), sex, age (<25y, 26-59y, >60y), number of vehicles involved, state, year of crash, and collision partner type (car, pedestrian, bicyclist, motorcyclist, heavy vehicle), and the various interactions/combinations of those variables. It's a very rigorous statistical method and I reckon it's a better guide than NCAP test results because it is based on real-world crashes. Unfortunately, it requires a certain number of real-world crashes to happen before a rating can be given, so it's impossible to apply to new cars. On the other hand, these ratings have proved that the improvements in car safety that have occurred over the last 20 years, which have been measured in new cars by increased NCAP star ratings, have demonstrably improved the total safety of cars in the real world.

[deviant]

I'm genuinely interested in this subject....

So with the MUARC report how do they adjust the figures for the final numbers?

Say if 100 cars crashed with enough damage to render the car undrivable (it busted the radiator) but at a low enough speed that nobody was injured would it be considered that that make / model of car is '100% safe' as 100% of the people involved walked away even if a crash going 20KMH faster would cause serious injury or a fatality?

No, that's not how it works. The MUARC analysis normalises for a wide variety of complicating factors such as the speedzone in which the crash occurred (<75km/hr, >80km/hr), sex, age (<25y, 26-59y, >60y), number of vehicles involved, state, year of crash, and collision partner type (car, pedestrian, bicyclist, motorcyclist, heavy vehicle), and the various interactions/combinations of those variables. It's a very rigorous statistical method and I reckon it's a better guide than NCAP test results because it is based on real-world crashes. Unfortunately, it requires a certain number of real-world crashes to happen before a rating can be given, so it's impossible to apply to new cars. On the other hand, these ratings have proved that the improvements in car safety that have occurred over the last 20 years, which have been measured in new cars by increased NCAP star ratings, have demonstrably improved the total safety of cars in the real world.

This is what I find interesting, the star based scoring system and crash tests show the NB to be a not particularly safe car but the real world shows that most accidents are survivable. Maybe it is just that the crash tests are particularly harsh or are not typical of an accident in Australia?

[Guran]

This is what I find interesting, the star based scoring system and crash tests show the NB to be a not particularly safe car but the real world shows that most accidents are survivable. Maybe it is just that the crash tests are particularly harsh or are not typical of an accident in Australia?

Huh? ANCAP gave 4 stars to the NB for a lab crash test and it rated as 5 stars in the MUARC study of real world crashes. That's a pretty close match in my book.

[Mr Morlock]

thanks to Guran for the explanations of the data. I reckon this data and information is really good news and informative- not just unfounded opinions.

Deviant remarked --"I believe the 2 silver hoops behind the headrests are not just for show. If it is anything like other modern convertibles those hoops will have an explosive charge underneath them (like an airbag) that will make the hoops pop up if the car tilts more than XX degrees. In the NC you also sit much much lower in the car"unquote. Well that is not correct- as per the first NC and now still on the Mazda site there is no mention of roll bars under safety. It is clear that Mazda does not claim them to be a safety feature because they are not. The hoops might look good and people might think they are adding something to safety but Mazda makes no such claim.

[Guran]

Well that is not correct- as per the first NC and now still on the Mazda site there is no mention of roll bars under safety. It is clear that Mazda does not claim them to be a safety feature because they are not. The hoops might look good and people might think they are adding something to safety but Mazda makes no such claim.

Sorry, but I have to disagree. What Mazda decide to say in promoting their cars is marketing not engineering. The decorative plastic hoops conceal a pair of fixed steel rollbars behind each seat, which are welded to a steel box-section cross-brace. They are clearly visible and described in the March 2005 issue of WHEELS (page 53). You can also see them in the photo below of a burnt out NC. They are not a fancy pop-up style rollbar like that used in the MINI Cabrio etc. It could be for that reason that Mazda don't make much noise about them. Likewise, they may not want to suggest that their convertible might be remotely susceptible to rollover. Who knows? But I know one thing. Mazda's engineers were anal about weight saving in the NC and there isn't a snowflake's chance in hell they would have tolerated a steel roll hoop under a plastic cover if that steel did not serve a real engineering purpose.

[Steampunk]

I also think it cant hurt if you get rear-ended by a 4WD, especially those with lift kits and roo-bars.

Yes, some lateral thinking needed here people.
This is the main reason I installed one, the probability of me getting rear-ended by a truck, bus, or one of the many soccer mums speeding in their BMW X5's is greater than going inverted.

[deviant]

This is what I find interesting, the star based scoring system and crash tests show the NB to be a not particularly safe car but the real world shows that most accidents are survivable. Maybe it is just that the crash tests are particularly harsh or are not typical of an accident in Australia?

Huh? ANCAP gave 4 stars to the NB for a lab crash test and it rated as 5 stars in the MUARC study of real world crashes. That's a pretty close match in my book.

The ANCAP test shown on howsafeisyourcar is 4 stars but if you read the text it shows that the passenger compartment was severely damaged and offers only marginal protection for the driver. One would like to think that 4 stars makes a safe car but the text tells another story but then the MUARC data shows the opposite again with them being a safe car in the real world.

Points and stars can be awarded just for fitting a seatbelt warning light or an electronic driver aid that does not improve crash worthiness so I still think the star system is a little bit misleading.

[Locutus]

depending on the ROP design, there is also an benefit when it comes to side impact protection.

i am sure i've read somewhere that the seatbelt tower bar in the NA8 was introduced to improve side impact safety in order to meet new standards. i'm not sure why it was removed again in the NB (surely the windblocker offers close to zero impact protection) but then again the NB came with more bracing on the underside of the car.

[Mr Morlock]

Lets be quite clear about the hoop bars on NC's. Mazda list all items related to the safety of their vehicle - and no mention of the bars- in other words they are not regarded as a safety feature
Some of the items mentioned are side impact door beams , one touch (down only) power window (driver and passenger), high backed bucket seats, day/night rear vision mirror. So they mention a rear vision mirror but not the hoops- would one be excused then for concluding that the latter is not a safety item? If it was why not mention it especially since many people already think they are. Insofar as construction is concerned this may only be done as a form of bracing. If anyone claims they are safety item then where is this information coming from?

[Guran]

This is what I find interesting, the star based scoring system and crash tests show the NB to be a not particularly safe car but the real world shows that most accidents are survivable. Maybe it is just that the crash tests are particularly harsh or are not typical of an accident in Australia?

Huh? ANCAP gave 4 stars to the NB for a lab crash test and it rated as 5 stars in the MUARC study of real world crashes. That's a pretty close match in my book.

The ANCAP test shown on howsafeisyourcar is 4 stars but if you read the text it shows that the passenger compartment was severely damaged and offers only marginal protection for the driver. One would like to think that 4 stars makes a safe car but the text tells another story but then the MUARC data shows the opposite again with them being a safe car in the real world.

Points and stars can be awarded just for fitting a seatbelt warning light or an electronic driver aid that does not improve crash worthiness so I still think the star system is a little bit misleading.

Oh I agree completely. It is absolutely shocking and surprising to see just how much damage is incurred in an ANCAP / EuroNCAP test for a car that achieves a four star rating from that test. But you know what? You should see how bad the three star cars perform. And a two star car is an absolute disaster - we're talking likely death for the driver and/or passenger from a frontal offset collision at only 64km/hr, or a side impact at only 50km/hr! The whole point is that these star ratings give a relative performance score of crash protection for new cars on the market. A consumer should never assume that because they drive a five star ANCAP car, they are immune to death or injury in a crash. They will merely be better protected than someone in a car with lower rating.

Bonus points for seat belt warning lights/chimes? Unbelted occupants are drastically over-represented in injury/fatality statistics. According to "Road Safety in Australia" (Australian Transport Safety Bureau, 2004), "each year up to 33 per cent of fatally injured car occupants (about 300) and 19 per cent of those seriously injured are unbelted." And yet seatbelt usage in Australia typically hovers at around 96%. In view of those figures, I reckon any initiative that encourages people to wear seat belts is worthwhile one and should be recognised in NCAP tests. The same argument applies to active electronic driver aids such as ESC, which have been proven to dramatically reduce the risk of severe injuries and fatalities in single-vehicle crashes (especially rollovers).