Neither of those. It's as Julien and M400 have said. Not sure how that would be dangerous, but I'm guessing you're thinking of a different application
It allows you to set a speed limit that the car can't exceed. you can then drive normally (brake, accelerate, coast, gear up, gear down) up to this limit. Unlike cruise control, it won't switch the limit off when you brake or clutch.
Essentially a comparator between throttle body position and pedal position. but rather than holding the throttle to the setpoint as cruise control does, it just stops the throttle from travelling open further than the setpoint. It's purely throttle control, not torque reduction / cuts.
The main variation I'd like to see is an adjustable version.
It's good for city driving, or motorway driving where the road may be a little congested and constantly varying speed, or to prevent those lapses of concentration where you might creep up over the limit. It's my preferred method for motorway travel. It's pretty common on the modern euro and jap cars.
