I have found that coasting even short distances as well as on hills has added many miles to each tank of gas. I have frequently added as many as 100 miles to each tank of gas.
I also coast on any grades and try to watch ahead for red lights. If you stay aware of the flow of traffic and the grades in the road you can coast and save from the reduced RPM's by disengaging the transmission from the motor in Drive to Neutral. It also reduces wear on the brakes too!
Happy Motoring and Coasting!!!