Unscientific Gas Mileage Test

Took a night drive on gentle rolling hills of Highway 280 to put the Elantra's 28 / 36 mpg fuel economy rating to the test.
I've been pretty purturbed at the poor city driving MPG: today on an errand to the city with highway miles and a lot of slow city driving I went down to 23.6 mpg at times. One of my requirements for my new car was that it would get better gas mileage than the Geo I was getting rid of. Some folk think they should upgrade/graduate to bigger more expensive cars. I want to graduate to more responsible cars. The Elantra does pollute less, but it is using more gas than the Geo.

This night test took place between 380 and Farm Hill Blvd exit. Going south I set the cruise control to about 62mph and cruised down. Or I could say 'up' since I think I was gaining elevation most of the time. It was 18 miles down to Farm Hill Blvd. The maximum MPG I got was 33.6.

On the return trip I decided not to use cruise control, my speed varied from 70 to 54 mph, but mostly averaging about 64 mph. On the trip back during a downhill grade I was averaging 36.3mpg. That was the max. When I finally exited on Millbrae Ave, it was back down to 35.7mpg. I cut the return trip just short instead of running all the way back to 380, since it had already show it could hit above 36mpg on this route.

Even though I kept a steadier and slower pace on the first trip(which should help optimize gas mileage), it seems the elevation gain made the engine work harder so the gas mileage was not as good as it was on the return trip.

Millbrae Ave is steep downhill for a mile or two and you can cruise down hardly any gas at all. There are several stop signs along the way, but by the time I got to El Camino Real the reading on the trip meter was an all time high 38.1mpg. Hills have a strong effect on gas mileage whether going up or down.

Conclusion: The Elantra's real world fuel economy can match its claimed 36 mpg on the highway.For the claimed possible 28mpg in the city, I really see no way to do it in a city like SF. We have too many lights, stop signs, hills, and cars. Maybe its possible in Irvine where the streets are long and posted speed limits can go up to 50mph.

(Added 11-3-07: Went up the hill to take a bike ride along Skyline and Sawyer Camp today...as we are continued to be blessed with unusually warm weather over 75° into November. Going up the Millbrae Ave hill I averaged 15.6mpg. Going down the hill I averaged 55.6mpg)