Vehicle: Road: Active
External regenerative braking   (+6, -2)  [vote for, against]
Braking energy absorbed and returned by mechanised road surface

I have read a number of regenerative braking ideas on here but they always seem to involve storing the energy within the vehicle for later re-use.

Braking often happens at predictable locations e.g. motorway exit slip roads. I propose that the road surface at such a location is constructed of lateral rollers, which are mechanically linked (perhaps by rotating shafts running beneath the motorway) to the entry sliproad on the opposite carridgeway.

Drivers leaving the motorway would brake hard to lock the wheels of their car, so all of the car's velocity is transferred to the rollers, and so across to the accelleration rollers which are speeding up the cars entering the motorway opposite.

There will be significant friction losses in the system, so the accellerating cars will have their gears engaged, but will need far less fuel to accellerate to motorway cruising speed.

Safety: there will need to be small disk brakes on each roller, acutated from within the car in an emergency, perhaps by blurtooth, or by reaching out of the car window to tug a penguin cord. Or perhaps a person can sit in a little cabin monitoring the system, ready to apply the roller brakes in the event of a pile up or other dangerous situation.

This system could be implemented wherever there is a stream of traffic braking, and another stream accelerating away.
-- pocmloc, Jul 26 2009

Personal Potential Cycling Counterweight Personal_20Potentia...ing_20Counterweight
using height to store braking energy [pocmloc, Jul 27 2009]

Halfbakery: elevated stop lights elevated_20stop_20lights
Re: decelerating hills. [jutta, Jul 27 2009]

Going from a (relatively) moving surface to a (relatively) stationary surface = lots of wear on the tyres, stress on mechanical parts, difficult to do for the driver, bumping up and down over the rollers, et cetera. Not so good, I'm afraid.
-- neutrinos_shadow, Jul 26 2009

[neutrinos_shadow], if the rollers were very small radius there would be less bumping. The first rollers would be almost still, the next moving a bit quicker etc. and this would match the acceleration rollers on the other side.

[bigsleep], wouldnt the hills have to be rather large to decellerate the vehicle from 80mph to nothing? This was covered by the bicycle potential energy idea (link).
-- pocmloc, Jul 27 2009

Expense, complicated, potentially dangerous [+]
-- coprocephalous, Jul 27 2009

[+] first time I have heard of energy being shared between people --- bring on the revolution!

Might not work well in america though... perhaps the amount of energy recovered from each car can be tallied --- just to keep those individualists happy....
-- madness, Jul 27 2009

safety brakes are actuated by blurtooth, yes, ohh, yes. Blurtooth. feel free to delete this at any time you want.
-- Sparkyplugclean, Sep 18 2009

And here's me thinking the regeneration is external to but attached to the car, like a big pop up windmill.
-- wjt, Sep 20 2009

random, halfbakery