回复：real world mpg

2400 miles, most highway at 70-80 mph, with A/C on all the time, used 84 gal gas. 2000 Sienna XLE, 3.0L, 1-2 people with 150LB luggage. This translates to 28.6 mpg. The listed gas mileage is 18-24 mpg - old gas mileage rating method. Just got this gas mileage and the car is 11 plus years old.

2006 Camry with old gas mileage rating method is 23-34 mpg. I used to get 37 mpg with 90% highway, 1-2 people without extra luggage and A/C on all the time. Got this gas mileage when the car was 2 years old.

But when drive at local I got only about 18 and 23 mpg, respectively - about the lower limit of the rated gas mileage. I am still happy considering this lower limit of gas mileages were assessed by old rating method.

The key to have high highway gas mileage is keeping constant speed as mucn as possible.