The road doesn’t have to be rough. Turning, braking, accelerating and just the normal vibration from any road surface would generate electricity. Heck, you could park the vehicle and jump up and down on the bumper and it would generate electricity. If the vehicle is moving, such a system could recover some energy from that movement.
If it's a truly smooth road, there is no normal vibration (wheels, tires and rotating brake components well balanced, tires round with a homogeneous carcass) unless an earthquake is happening.
Braking?? What's that? Coasting up to lights and stop signs is de regur. Not smacking the brakes minimizes suspension movement. Same with smooth use of the loud pedal.
Curves? depends on the locale. Not too many on the road for me.
You'd be better off putting some pedals at each passenger seating position and makes the galley slaves turn a generator as you drive along.
Gives a whole new meaning to “jump start.” Imagine asking passers-by to jump on your car to recharge the battery.