[Zigurd]

By and by, enough cars will be equipped with enough driver assist that heavy cars that must be crashworthy at relatively high speeds will no longer be needed, much in the way active safety makes light high speed rail carriages possible. Then lightweight vehicles can come in to wider use. Imagine how road capacity would be increased by something like a lightweight one-seat series hybrid "bike" with an enclosing fairing. A lot of communities could be done in vehicles weighing 5-10% the weight of a car.

[jacquesm]

Yes, this is definitely a good point. There is an arms race like effect at work here, if you could de-escalate that lighter vehicles would be much better.

[femto]

One wonders whether there is a place for "Active Crumple Zones"? Instead of a car having to weigh more that the opposition, it carries an explosive charge in it's nose, which is used to provide a burst of forward momentum to the leading edge of the car during a crash, preventing it from being forced back into the passenger compartment. One can imagine refinements, such as inertial sensing and a feedback loop to control the size of the discharge, so the "virtual" weight of the light vehicle matches the vehicle that it is colliding with.

Count this as idle speculation rather then a serious proposal! Mind you, if a bike was equipped with such a system a 4WD owner would get a big surprise when they ran into a cyclist and got like-for-like.

Edit: I guess I'm really describing Reactive Armour for everyday vehicles.

[CRConrad]

> Instead of a car having to weigh more that the opposition, it carries an explosive charge in it's nose, which is used to provide a burst of forward momentum to the leading edge of the car during a crash, preventing it from being forced back into the passenger compartment.

> Edit: I guess I'm really describing Reactive Armour for everyday vehicles.

Or basically an external airbag.

[rootusrootus]

> "virtual" weight of the light vehicle matches the vehicle that it is colliding with.

I imagine physics would intrude at some point and make this a non-starter.

[jacquesm]

Collision with a pedestrian as well.

[boogies]

How powerful and effective could that be without launching the lighter vehicle backwards with dangerous force?

[femto]

From a purely theoretical point of view, if there was a perfect feedback control loop the energy of the explosion could be controlled to bring the front of both vehicles to a perfect stop. Both vehicles would then crumple about that stationary point.

From a practical point of view ...

[jacquesm]

Trying to imagine two such vehicles colliding head on...

[jacquesm]

Oh that's evil :)