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It really depends on the grade and length of the hills. My local area has hills like Interstate overpasses. The hills get steeper when I go west. I've done a lot of local driving, basically living here for almost all of the 40+ years I've been driving. With the Fiesta's factory MPG gauge as well as the ones on my Altima and CVT first gen Insight (both sold and gone) I have developed some tricks to utilize hills for better mileage than perfectly flat ground.
Very gradual acceleration (in top gear) cost very little in additional fuel consumption. If the hill allows you to maintain your coasting speed then hit the top of that hill at the speed limit. That's about the steepest hill here, very few will allow the vehicle speed to increase above 45 MPH, so on any congested road I look for some drafting help to maintain my coast above 45 MPH.
Some hills require a completely different tactic. Thes are short duration but slightly steeper hills. On these I will gradually accelerate approaching the hill and go neutral coast up the hill and regain my speed downhill. My highest speed is close to 60 MPH (55zone) and at the crest of the hill that speed will drop to 40 MPH. This avoids the hit in fuel economy I would see if I just let the hill increase my engines load trying to maintain a constant speed. I regain most of my speed coasting on the down slope of same hill.
Other very shallow hills I will P&G on the upslope and even sometimes on the downslope. Again I am using very gradual acceleration, like 10 seconds to increase my speed by 5 MPH (faster on the downslope). This allows me to avoid any 10 MPH over situations where the roads are heavily monitored by the local police, while also not being too great an impediment to traffic.
In every instance I try to maintain a speed of over 40 MPH. In the Fiesta that is where it goes into 6th gear. I also try to avoid any load where the transmission shifts out of 6th gear at speeds over 40 MPH.
My speed peak and low points depend on surrounding traffic. If it's heavy I look for a big rig to fall in behind and pulse-draft. If lighter then I increase my speed differential range, but in both cases I try to avoid impeeding traffic flow. If someone wants to plant their nose up my rear end this tactic also serves to frustrate them enough so they pass me, just thinking I am an old geezer who can't drive worth a darn. Little do they know.
All the cars in this response were automatics. I need one in case the wifes car becomes undriveable for any reason, and with the congestion here you avoid crawling through a 1 mile 1 hour nightmare in a manual.
regards
Mech
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