I have a idea for improving fuel efficiency in city driving. Assuming that everything else has been done on ones car to improve FE such as: tweak tire pressure, grill blocking, engine block heating, proper oil viscosity, proper driving technique. ... one of the remaining significant drain on fuel economy is stops/starts due to traffic congestion and intersections. Even with regen brakes and ICE shutoff, it still takes energy to bring the car to a complete stop and then to get it rolling again. 1. Optimize for road grade, preferring downhill over flats, flats over uphills. On my daily commute, there are some traffic lights that I'll prefer to avoid because the lead-up to the intersection is uphill. Conversely, I'd prefer to be on a downhill grade if I do need to stop due to traffic conditions. 2. Optimize choice of intersections to favor those that allow turn on red lights. This will reduce the time spent stopped at a red light, and reduce the amount of engine cool down. And reduce travel time. I don't think that there are any turn by turn mapping systems that take these factors into account. I don't think there are many databases that have these factors captured for urban intersections. At the same time, these factors if taken into account, will improve any driver's FE, no matter the car. Any thoughts?