Do we have to drive a tank?
November 11, 2012 9:12 AM   Subscribe

Since car safety ratings are based on equal sized cars, how can I maximize safety while minimizing size?

Help me think about car safety across vehicle classes.

I'm thinking of the problems with current safety ratings detailed here. I would also appreciate any advice on small, fuel efficient cars that maximize passenger safety regardless of what they get hit by.

I want to buy a Toyota Prius C. I suspect I should buy a Volkswagen GTI. (Or a Land Rover.)
posted by anotherpanacea to Travel & Transportation (13 answers total) 1 user marked this as a favorite
 
Remember that the maneuverability, sure footing and quick braking of smaller vehicles helps you dodge accidents. Yes, you will fare worse in a direct collision with a large vehicle, but car-on-car accidents are not just an inevitable test you will have to survive.

In the past, small cars might have had better visibility too, but now all cars have this stupid high-waisted design that's impossible to see out of.
posted by scose at 10:01 AM on November 11, 2012 [1 favorite]


Remember that the maneuverability, sure footing and quick braking of smaller vehicles helps you dodge accidents.

This is not to be underestimated. This is referred to as Primary Safety in the automotive safety - the ability of the car to avoid the accident in the first place. Vehicle handling, ABS, anti-skid/stability control and the like are all part of primary safety and small vehicles (with lower mass) are much easier to control in those situations than a larger car. Momentum is a difficult thing to overcome, after all.

Crash safety is an issue, because the larger vehicle generally wins. Especially if the larger vehicle is going faster. You really just need to get the vehicle in your size class that has the best crash protection passively (within its weight class) and then make sure that your own personal primary safety (ie good vehicle maintenance, especially tyres for the conditions and competent driving skills and road awareness) makes sure you are less likely to be in an accident anyway. It doesn't matter how awesome your crash safety is if you never hit anything, after all.
posted by Brockles at 12:30 PM on November 11, 2012


Car safety also depends on where you do your driving. Most fatal accidents occur on (non-interstate) highways that are usually two lane roads. If most of your driving is in town, then that isn't so much a concern.

Also, most fatal car accidents are single car accidents.

So, you don't need to drive a tank. You need to drive well. What Brockles said about primary safety is key.
posted by Pogo_Fuzzybutt at 2:31 PM on November 11, 2012


how can I maximize safety while minimizing size

First, what's your priority? Size or safety? In a head-on crash, they are mutually exclusive. In a single-car or side-impact crash, they're not. You need to decide your risk tolerance for having a particular type of serious accident.

If size is your priority (i.e. you really want a small car), then get the biggest small car you can stand (a compact like a Golf/Civic/Cruze etc. rather than a sub-compact like a Prius C). And when looking for that car, get the one with the best NHTSA and IIHS ratings. In particular, note that NHTSA ratings since 2011 have been significantly tougher than before.

If safety is your priority, get a mid-sized car, in particular a hybrid or a diesel. You'll be way better off in a head-on crash in a new Camry or Fusion hybrid or a Passat diesel than you will in a Prius C, and you won't use that much more fuel. Maybe wait until the IIHS announces the small-overlap test results for midsized cars, if you're buying new.
posted by Dasein at 9:26 PM on November 11, 2012


Cars are getting safer and safer. For example, rear impact injury protection has improved a lot lately with more widespread implementation of active head restraint technology, and I've also heard the steel that is used these days is much stronger than before. So getting a newer model that has a high safety rating is probably more important than thinking about vehicle size (weight). If you look at the IIHS lists, there are many small and economical mid-sized cars that get top safety pick. You can also compare with the US government crash test data on SaferCar.gov. One other thing you might want to look into that may not be on those sites is roof crush test information. My understanding is that the US government standard is not all that great but some makes (for example, perhaps Volvo) exceed the standard. My colleague just last week saw a freeway accident in which an overturned vehicle's roof was completely crushed. Obviously, you wouldn't want to be in a vehicle like that. I'm quite focused on vehicle safety in my own vehicle selection process, and what I do is avoid buying a really small car but I also don't get a tank. I have a Volvo XC60 and my wife has a Volvo SC60. The other thing I do is lease for three years so I can upgrade to the latest safety features on a three year cycle. Personally, among vehicles that get top safety ratings, I still trust more the manufacturers that have a long history of emphasizing safety, such as Volvo, Subaru, and a few others.
posted by Dansaman at 10:31 PM on November 11, 2012


Thanks folks. Two issues:

My family has been in several accidents in sub-compacts, but never in a large sedan, possibly because very small cars do poorly on ice. That undermines the case for the primary safety of small cars to me.

My wife was t-boned by a Saudi prince ignoring stop signs in a brand new convertible a few years back, so we're perhaps more anxious about passive safety features than we need to be. This may just be a hasty generalization from too few cases; you're always protecting against the last accident, etc.

I'm not sure I've got the information I need yet, but we've got a lot of time to make the decision. I'll be spending more time with the NHTSA ratings, to be sure.
posted by anotherpanacea at 5:01 AM on November 13, 2012


because very small cars do poorly on ice.

This is not necessarily the case and I think it is a flawed conclusion that varies much more on other factors than size. Did they have the correct tyres on? Don't use all seasons, use winter tyres. NO cars do well on ice without the right tyres and I certainly don't see this 'small cars aren't as good on ice' conclusion being supported in Canadian winters. The smaller front wheel drive cars go barrelling past me in the snow (in my heavy RWD car) with almost no problems by comparison. I've driven in the same conditions (same day) in rear wheel drive and little front wheel drive cars and with the right tyres on its no big deal.

The reason people put weight into cars in the winter to gain traction is that the car is fundamentally flawed in its ability to create its own traction - either through tyre choice or through suspension design. You don't need to put weight into a car that is capable of generating grip through being well designed and maintained. I drove a Prius in horrific ice and snow a few years ago and it was phenomenal because it belonged to the daughter of the company owner and he didn't mess around or try and save money when he bought her winter tyres. I could drive completely normally as if it was a dry road while people slithered all around me. You have to compare like for like.

My wife was t-boned by a Saudi prince ignoring stop signs in a brand new convertible a few years back, so we're perhaps more anxious about passive safety features than we need to be.

There is no planning for this kind of freak accident in car purchasing choice. You kind of need to let that one go, as I think you know deep down. Side airbags and a good crash rating are as much as you need in that instance as comparative vehicle weight isn't as much of an issue as your own momentum isn't so much in the equation.
posted by Brockles at 6:35 AM on November 13, 2012


Just another anecdote about small cars on roads with snow and ice, my Mini Cooper was the best car I've ever driven on bad roads. Better than my Civic or my GTI, hands down.
posted by Brian Puccio at 11:17 AM on November 13, 2012


Thanks for the datapoint! Mini Coopers are actually really heavy, right? I've heard the reason that they have relatively low fuel efficiency is because of the weight.


comparative vehicle weight isn't as much of an issue as your own momentum isn't so much in the equation.


It's been a while since high school physics, but this sounds wrong to me. Isn't more inertia better than less, when your momentum is negligible? I'm worried (however irrationally) about getting plowed into by an SUV. I hate SUVs, minvans, and all that crossover nonsense, so I want to be wrong on this, but presumably we would fare better if we had an SUV of our own?
posted by anotherpanacea at 11:39 AM on November 13, 2012


Mini Coopers are actually really heavy, right? I've heard the reason that they have relatively low fuel efficiency is because of the weight.
Sorry, neither of your points here are correct.

According to cars.com's vehicle comparison utility, a 2012 Mini Cooper gets 29/37mpg, beating a 2012 Civic (2 door EX) which gets 28/36mpg and a 2012 GTI (2 door) which gets 21/31mpg.

According to the same site, a Mini Cooper weighs 132 pounds less than a Civic and 467 pounds less than a GTI, that's a 15% difference in weight!
posted by Brian Puccio at 12:02 PM on November 13, 2012


Isn't more inertia better than less, when your momentum is negligible?

It's swings and roundabouts in a crash, to be honest. More weight and inertia means your car has to crumple to absorb the impact, less weight and inertia means your car is more likely to be moved out of the way, in which case if you have side airbags to reduce whiplash or hitting something solid when you are moved sideways, it's not that different.

So you could say that if you get hit by an SUV, then your small car will crumple a little, then slide away from the SUV. If you had an SUV, then your car would crumple more and not move away. But your smaller car is much more capable of avoiding an accident in the first place than an SUV.

If you get hit by a tractor trailer, then your little car will likely bounce off (or be more inclined to) or crumple a lot. Your SUV will just crumple a lot. Your small car also was much more capable of avoiding the accident in the first place.

Crash safety is not just a case of 'this is better than that' because of the massive variables involved and the hugely different energy pulses in the kinds of accident you can have. Bigger is not always better, unless you know you are going to be hit by something bigger than you. Even then it isn't always a linear scale - if something is MUCH bigger than you, then having a slightly bigger car ay make no difference or be worse.

The only safe answer is to have the BIGGEST car on the road with good crash safety. So buy a tank with internal air bags. That is really the only way to make sure you have the best odds. Otherwise, you need to consider the likelihood that having the same crash again is phenomenally unlikely and just pick a good crash test rating for the size of car you need. That's the only answer there is; everything else is over-thinking, frankly.
posted by Brockles at 12:14 PM on November 13, 2012


very small cars do poorly on ice

I haven't heard this. In any event, ice can be dealt with by driving at appropriate speeds and, more importantly, getting good winter tires, like the Michelin X-Ice Xi3.

My wife was t-boned by a Saudi prince ignoring stop signs in a brand new convertible a few years back

I agree that convertibles are not the best choice for passive safety in side impacts. However, small cars can do as well in side impacts as large ones, and side-impact scores in side crashes are directly comparable across weight classes, because there's no advantage to being in a heavier car; what matters are the side-impact structures in the door and frame, your seating position, and the way the airbags deploy. The advantage of an SUV in a side impact from another SUV would be your seating position - better to have your head clear of the other SUV's bumper. The IIHS tests side impacts simulating an SUV/pickup bumper for that reason.
posted by Dasein at 3:14 PM on November 13, 2012


To be clear, my wife was driving an ancient Honda Civic hatchback. The prince was the one in the convertible. Since it was brand new, apparently, he didn't have car insurance, so there was no one domestic for us to sue. Yes, I am bitter.
posted by anotherpanacea at 3:53 PM on November 13, 2012


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