Hi,
This is my first
mph vs MPG chart and it shows two
knees in the curve:
This chart of 1.5L, NHW11 mileage came from gas receipts when I was topping of the tank twice a week.
The two knees are:
- 65 mph - anything over this speed and mileage takes a dive. At 70 mph, it is 49 MPH but hills and headwinds really take a toll. A 5 mph guard band minimizes these effects.
- 38 mph - at 40 mph, the city mileage takes a serious dive compared to just a few miles per hour slower. The Prius has a critical transition speed, 42 mph, so having a 'guard band' avoids this bad speed. Or driving 46 mph, puts the car above this critical speed and into another efficient band.
Route planning is also important and this takes experimentation. I was using my wife's 2001 Echo until we got the 2003 Prius:
Not shown are the different routes tested but the key is the Echo does best by avoiding stop-and-go traffic. Both cars benefit from a slow-speed, neighborhood warm-up. In contrast, the Prius does great in stop-and-go which means I can use short-cuts that would negate the Echo mileage as it heats the brake pads.
Both cars have nearly identical sized tanks so direct and indirect costs:
- Echo - fill-up every two weeks.
- Prius - fill-up every three weeks.
Bob Wilson