City vs Highway
 

When adding a fuel-up, do you use the proportion of time or the amount of mileage spent in each driving condition? My daily journey from Dover to Canterbury by time would be 65/35 split, but by mileage would be 20/80.

I go by mileage. The EPA city test doesn't reflect modern heavy city traffic with frequent stops. Plus, at long lights I shut off the car. At least, when it is above freezing.

Personally, I think it is a useless feature and don't use it at all. I did consider using it with my pickup, using City for the miles spent pulling a trailer and Highway for the miles without.

My experience, with my vehicles, shows city mileage runs about half to two-thirds of mileage on the highway.