Mileage?!!!

Starting with a cold engine? That is nuts. The only Toyota info I really pay attention to is the odometer, at every fill up. Just for laughs I record what Toyo tells me, and it's a very consistent 7.5% optimistic. But yours has reached a new low in misinformation.

 

My guess is that you drove on some slow roads around 45 mph (72kmh) and stayed almost entirely on battery. Its not unusual to get 99.9 mpg over short distances if you had a full traction battery and drive slowly.

 

10km is a lot further than the battery will go, was it downhill?

 

... especially if the trip segment also includes elevation loss.

 

I haven't gotten 100, but I have gotten 72 over a 7.5 mile trip from the library. Some of it is somewhat downhill and there is a 1/2-3/4 mile segment that tends to run in EV mode. Unfortunately, such short trips mean almost nothing in the big scheme of things.

 

I've met or beat 72 on numerous round trip commutes (two cold starts, several thousand feet of gross elevation change but zero net change) of 36 miles. Also did these, first was a round trip very shortly after getting the car, second was a one-way:


But others have done far better in the right conditions. Don't we have a 100+ MPG thread, for whole tanks or extended distances, somewhere here in PC?

The hard core Japanese hypermilers surpassed 100 mpg for whole tanks long ago. As I posted to another thread:
Another World Record 1,460 miles/tank | PriusChat
1,562 miles, New World Record with a single tank | PriusChat
New World Record - 1619 miles per tank | PriusChat
New World Record - 1680 miles per tank | PriusChat
New World Record Challenge: over 50km/L(117mpg) tank | PriusChat
That final one went 1889.4miles, over 3000 kilometers, with a final result of 118.6 mpg.

So OP's 100+ MPG short trip is not necessarily silly at all, it could be the realistic convergence of skill and the right conditions.

 

I guess so. Because of the stop engine idle tech - Once you get a Prius started a certain speed you could just coast downhill for 10 km without turning on its engine - all you need a smooth road surface with a fairly straight road direction an elevation/attitude drop between your starting point and end point, reasonably warm driving temperature, and the wind behind your back..To eliminate the cost of the warm up you set the Prius trip odemeter to zero after you warm up the car.... the most accurate way to determine the real fuel efficiency is to divide the miles driven between the gallons use to fill up the gas tank after the first automatic fuel pump shutoff click

You can also use a Scangauge II AVG meter which is pretty accurate.

Today
going downhill my regular 15.8 miles it estimated I was getting 79.8 mpg
going uphill my regular 15.8 miles it estimated I was getting 60.1 mpg
so my average is about 69 mpg today...
The Prius says my average fuel efficiency for the last 290 miles is 67 mpg but it is usually about 3 mpg optimistic. At 64 mpg - I think I can do a 700 mile/tank..

my commute elevation change is from about 480 feet to about 300 feet