Coasting and power steering

If you are like me who does not enjoy the buzz of the automobile engine, then surely you would be tempted to turn off the engine while taking a long cruise down the hill (on a road/highway of course). My father used to frequently do that when he drove his Fiat Padmini. It’s also good for the environment because anyways the engine power is no longer needed while cruising down a hill. However no matter how much I desire to do that, recent advancements in car technology require the engine power to operate the power steering and power brakes. Theoritically one can still steer and navigate in a modern car with engines on, but the performance, response time (and effort required) would take the joy out of a nice eco-friendly road trip.

I wonder if there is a way I could have the best of both the worlds.