Be aware that for global NCAP, safety ratings are dependent on the vehicle class. If a subcompact car receives 5 stars, this does not mean it has the same probability of survivability in full frontal crash as a large executive luxury sedan that received 5 stars.
In fact, if there was a head-on crash between this car and Mercedes E-Class, and you're planning to be in one of the cars, I would advise you to chose the Mercedes.
Yes. Anyone who has worked on conservation of momentum problems in high school physics should recognize this. Even at low collision speeds if there is a large disparity in mass between the vehicles then the lighter one experiences a lot of acceleration.
For an extreme case think of a low speed collision between a bowling ball and a ping pong ball.
In a mismatched collision, the smaller vehicle needs to withstand a higher delta-V than the larger vehicle.
Also, in many cases the bumper heights are mismatched so the larger vehicle's strong structure runs into higher, weaker parts of the small vehicle, further exacerbating the problem.
There are several things you can do to dramatically reduce your risk. Cycle during the day, while sober, with bright colors, with a helmet, and avoiding multi-lane roads. If you do these things you've statistical eliminated most of the risk.
> victim blaming
It's an exercise in reducing risk, not assigning blame.
> the law says I can cycle on those roads
The law can't bring you back to life, but if you want to take the risk that's your decision.
We need to think more game theoretically. Since our courageous cyclist must already have a deathwish to be on the same roads as these vehicles, he should go all in with a vest packed with C4 and ball bearings so that, in the event of a crash (which will cripple him anyway), at least he takes out Starbucks Mom on his way to Paradise.
If you do as I suggest then you eliminate a lot more than 90% of the risk. 62% of cyclist fatalities weren't wearing a helmet, so that alone is a huge thing you can do to improve your odds. 22% are drunk. 50% are on major roads. https://www.iihs.org/topics/fatality-statistics/detail/bicyc...
I knew I would get responses about "why don't cars just..." e.g. why should I change, they're the ones who suck. I'm not suggesting or opposing public policy changes here. I'm giving practical advice which makes cycling much safer than the statistical average.
If you do all of what I say, it's a reasonably safe and healthy pastime.
People who bike for transportation, not just fun, sometimes need to bike at night, on less bike-friendly roads, or without high-visibility clothing. It doesn’t seem to me that the sentence for that should be death.
Please, try to get some high-visibility clothing.
The difference in visibility is between hundreds of meters with high-visibility clothing and meters without.
> It doesn’t seem to me that the sentence for that should be death.
Maybe not death but severe injuries.
Being visiblevin the night is a game changer.
"You" is singular as a cyclist. Wearing appropriate gear can drastically improve your (again, singular) safety.
"You" is plural for motorists. A single motorist deciding to own and operate a soft-and-safe-mobile will not affect your (singular or plural are interchangeable here) risk appreciably.
It doesn't mean you're wrong, and you (singular) can pick your battles, but I think I'd prefer to be alive than correct.
With electric bikes there is the possibility of adding safety gear to bicycles since the extra drag can be offset by motor power. Even just the simple example of allowing the rider to wear better, motorcycle-style protective gear would be a massive improvement - since they aren't pedalling so hard. Such gear could be actively heated/cooled as well.
Since the heavier vehicle has higher momentum, it would decelerate slower when hitting a semi-static-object, which decreases the forces on your body. The smaller vehicle would stop much quicker and you would jerk forward. So a heavier vehicle at the same speed would probably be better, all else being equal. And that's neglecting the additional material a larger vehicle typically has that deforms over longer distance than with a shorter car.
So many are and some aren't. So in many cases it doesn't matter which car you're in, and in some cases the heavy car is better. That means the heavy car is still net better.
I still haven't seen a single argument why a smaller car would be better in a collision.
But a small car doesn’t perform better, why would it? Surely a large car is better when driving into an electrical pole than a small car. What advantage does the small car have?
Also, just to clarify, how did I change the problem? The problem with car crashes is rapid deceleration which injures you, and lighter cars are worse in that aspect compared to heavier cars.
And can you explain why less momentum is better for the passengers? The thing that injures you in an accident is acceleration (or more accurately deceleration), so you actually want more momentum.
Imagine sitting in a large truck vs a kei car and driving into a brick wall. One has the chance to deform the wall which decreases the speed comparatively slowly. The other one abruptly stops when hitting the wall.
Unless the collision target doesn't deform at all, the higher momentum is better. And if the target is completely solid, a larger typically has a larger crumple zone which is better, too.
I cant come up with any reason to prefer the smaller car/momentum, except in very constructed scenarios (driving over a cliff with a weak fence for example).
If the object is completely fixed and effectively inelastic, the main determinant in survival is the distance over which the deceleration of the occupant occurs, assuming a lack of cabin intrusion.
So the mass of the vehicle is ideally fixed in relation to its rigidity, and it’s not better to have less, or more, mass except as the ideal ratio to the rigidity of the vehicle.
What you want is a vehicle that decelerates as slowly as possible over the greatest possible time/distance.
A light vehicle that is very rigid is equally terrible as a heavy vehicle that is very rigid. What matters is how many millimeters it takes for each vehicle to come to a complete stop after colliding with the immovable object.
There are a lot of combinations of vehicle mass and rigidity that meet the ideal here, and it is not sensible to assert that a massive or a lightweight vehicle will be ideal in this case.
What you want is a vehicle that, at the speed of the collision, deforms the most completely and to the longest distance possible without incursions into the passenger compartment.
Ideally, the vehicle would have a very long and well engineered crumple zone in front of the occupants. Here, assuming similar material engineering of the impact absorbing structure, length is king. All things being equal, a car with a stubby front profile will expose its occupants to twice the acceleration as one with a 2x longer hood.
Still, the vehicle must have enough mass that the crumple zone is fully compressed at the speed of the collision. If it’s too light, it will decelerate before the impact absorbing distance if fully used.
If it’s to heavy, it will still be moving when the crumple zone is fully exhausted, and either a sudden peak of acceleration or a cabin intrusion will occur when the passenger cage becomes involved in the deformation zone.
I’m going to guess that on average, you’re still better off in a full sized SUV than In a more sensibly sized vehicle, hitting an unmovable object at speed.
You say you have a background in vehicle safety, so maybe you know something I don’t. Please explain where I’m going wrong here?
All things being equal, this is generally a little bit true, even for collisions with rigid, fixed obstacles - but vehicle design is critical here. For instance, a cab forward truck with no real crumple space does not benefit from mass, as the deformation of the pax compartment is the primary concern. A very lightweight vehicle that is very deformable and has a long crumple zone might outperform a heavier vehicle in terms of the acceleration imparted to the passengers.
The problem is that a “fixed” solid object has effectively infinite mass. This applies when the collision displacement of the obstacle can be measured in fractions of a millimeter. In these cases, the ratio of the lightweight vehicle to the effective mass of the obstacle is effectively the same as with the heavier vehicle vs the obstacle. Here, mass pays no dividends. Only the distance / time covered during the sudden deceleration, and the integrity of the passenger compartment. Of course, the efficiency and extent of restraint systems will also play a major role. But it’s not an automatic win for heavier vehicles in this case.
Notably, most collisions are not with immovable objects, but with other vehicles. In that case, mass is going to win almost every time, since the acceleration experienced by a subcompact vs a full sized SUV is about 2x, which means the forces imparted on the passengers in terms of static loads on their bodies and bones will be 4x.
For passenger survivability in most accidents, the incentives fall heavily towards using the heaviest well constructed vehicle that you can afford.
Crumple zones have been a thing for almost a century.
Momentum doesn't matter. It matters in a vehicle on vehicle collision, but since the pole is essentially infinite I'm not sure why you're bringing it up. Acceleration is what impacts the human body, and it's determined by speed and distance. For the same speed, a larger car will have a longer distance to stop, therefore lower acceleration, and less force on the body.
Even if you assume that the pole doesn't move at all, having less momentum doesn't help you. A smaller car isn't better, in the best case it is equal. But a larger car probably also has a larger crumple zone so it is still better. You still haven't given a single reason why a smaller car would have an advantage.
awesome, i will only buy ford f150s from now on so i can have the most mass during any collision and thus will never be on the worse end of a collision. is it really american if you aren't screwing over your peers?
I was curious (but also lazy) so I went and checked Wikipedia. According to that source, the newest model of Ford F-150 is the fourteenth generation one, so let's look at the numbers for the top-of-the-line Raptor (or what I assume is the top, I'm not a pickup person). Assuming largest manufactured dimensions in all cases for the truck and smallest for the tank:
Just a thought process.. how bad would a f150 <~> f150 collision be, compared to say VW Golf <~> VW Golf?
If everybody went with f150, and the chances of colliding with another heavy one increases right? In the end, the edge is only short lived right?
I guess this means "vehicle safety ratings" only take into account the safety of those inside the vehicle? In a better world the safety of those outside of the vehicle would not only be taken into account but weighted more heavily, which would mean small cars that are safe for the occupants would get the highest ratings. Sadly we not live in that world.
relative rating or not, it has been successful at pushing car manufacturers to make safer cars, at least in the region the article talks about.
recently it has become a selling point to have a 5 star safety rating for cars in the market, which has finally made basic aspects like airbags part of the cheaper trims.
This seems like a clear case for government regulation over libertarianism, because who else holds the interest of this sort of social good at the scale of all cars driving the roads?
The personal moral dilemma here is crazy. Are you willing to risk your own life and the lives of anyone else in your car over the lives of the people in the other car? It's so terrible but you also can't fault anyone individually for choosing a larger car for safety reasons. (Those reasons being, I would prefer to kill someone else than kill myself or others in my car.)
In fact, if there was a head-on crash between this car and Mercedes E-Class, and you're planning to be in one of the cars, I would advise you to chose the Mercedes.