So long as there is sufficient space between the hood and the engine, which tends to be the main issue with very low cars. Sheet metal deforms as a pedestrian bounces off of the hood, increasing the interaction time and decreasing the instantaneous acceleration. This requires at least 10 cm between the bottom of the hood and the top of the engine. Less distance, and a pedestrian instead bounces off of the engine block, which doesn't deform on impact.
You can see in the video that it’s true. In their experiment, the lower hood, at same speed, makes the pedestrian hit the car 3 or 4 times instead of twice with the taller vehicle.
Mind you the taller car was only about elbow height, not like some lifted trucks you see these days where the bumper roughly aligns with a person’s hips.
A big factor is the height of the hood. When a smaller car hits a pedestrian, the hood is usually at or slightly under the pedestrian's center of mass, so the person will often roll up onto the hood. In a bigger car the hood is substantially above the center of mass so that a person cannot roll up --- they end up being forced under the car, which is much more dangerous.
Is that true? My understanding is lower hoods roll pedestrians over, whereas tall, solid hoods basically bring them to full speed immediately, doing a bunch of damage in the process.
The overall height, especially of the hood is also really important for the pedestrian's chances. if a sedan hits you, ideally you can roll over the top. if a truck or suv with enough size hits you, you go under it.
This is not true - there are other factors at play. The angle of the bumper and where the bumper comes into contact with a human matters a lot - if it is below the human's center of mass, they are much less likely to be thrown under the vehicle and run over.
Some passenger cars also have a nifty feature where if an impact is detected, the hood on the side of the windshield is instantly propped up by some springs to provide a cushioning effect to whoever ends up on the hood.
I've seen it action when a guy who I was riding motorcycles with got hit on the side by a car (his fault, low speed, he was fine). My car also has the feature.
Obviously impossible if the hood's too high like with an SUV or pickup.
Some poor understanding of physics in many comments. High school physics deals in point masses in vacuums, but people and vehicles are not point masses.
Injury is closely correlated to accelerations applied to various body parts. A sloping hood gives more space to average out the acceleration.
Conversely my stepfather blacked out and fell backwards on a tile floor. A low speed impact with a high acceleration applied to the back of his skull and brain that killed him.
As a driver you mostly care about the amount of deceleration you will personally experience.
If you have 1m of hood to work with, you're decelerating 100km/h to 0km/h over 1m in the wall case.
In the hood-to-hood case, depending on reference frame, you're either decelerating 50km/h to 0km/h over 1m or 100km/h to 0km/h over 2m (both hoods).
Either way it should be trivially obvious that running into a wall is going to be a much more violent experience. Likely the wall crumpling up the front of your car won't be enough to bring you to a stop before you personally impact something.
> A modern car have deformation zones and angles for you to basically slide along -
That protects the people in the car, not those outside. Being hit by those deformation zones _will_ hurt.
There is one thing that makes modern cars less dangerous to pedestrians, and it's that when someone is hit by a car they are more likely to roll over the hood than under the wheel. HOWEVER this is only the case for sedans, and definitely NOT for SUVs. Now look at the proportion of SUVs in your area.
Also, shape. Go look at the front end of a car like a ford F150. The hood is flat and sits 4 feet high. Now go look at a more compact car like a prius. The hood is low, and is angled like a wedge smooth into the windshield. When a prius hits you, its liable that you will just roll up and off of it and not get much of the force from the impact as a result. When an F150 hits you with its 4 foot tall wall of a grill straight in your chest, I don't think you will be rolling up and over. Maybe your head would just pop off from the kinetic force, sparing you from a slower death?
It depends. At like 80kph, you're pretty screwed from the impact alone regardless of the vehicle. At 15kph, both are pretty survivable from an impact perspective. But if your survive the impact, the next question is where do you go? For big, raised, boxy vehicles, the answer is more often "under the car" than for cars with ramping low fronts. Having the weight of the car on you is dangerous by itself, even at 1kph.
Then of course there's the impact of the design on driver visibility and therefore accident frequency, especially if the pedestrian is a child, short, in a wheelchair, etc.
When pedestrians hit the bonnet or windscreen of a car, the impact is relatively soft.
The A-pillar or the engine (under the bonnet if there is not enough space between the two) are much more dangerous. Some cars have an active bonnet that can spring up to make room and give a softer landing.
Why don’t you just limit the speed of the car to how much impact it can take without seriously injuring the passéngers and possibly pedestrians? That car can’t take a 40mph impact but maybe it can take a 25mph one?
Note that this does not address the fact that high bumpers are death for pedestrians. This addresses the issue of collisions with cars, but tall vehicles in general are really bad for pedestrians.
Even when the minimum braking distance is not small enough to avoid hitting a pedestrian, a lower speed will impart a lower kinetic energy vastly reducing the odds of fatally injuring the victim.
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