100 miles on my new 2007 Prius ....

In my experience, yes, until you are up to speed.

 

Yup.

If it is fairly hot out or the car has been running for awhile I will usually see low 12s or high teens when accelerating from a stop.

When it's cold out or the car is not warmed up it will sometimes drop to single digit mpg for a second then sit in the teens till I get up to speed. That's usually only when it's cold or I am accelerating briskly.

 

As the others have mentioned, you will get you worst fuel economy (in general) when accelerating up to speed. However there are numerous threads on here that discuss how to best use that speed, so your energy is not wasted.

Its a learning process, but one that will reward you with better FE over time. Good luck!

 

Just imagine what the fuel consumption is in other vehicles that don't have a real time display of MPG>.....

 

If you want better mileage, don't accelerate slowly. Assuming we are not talking about creeping from stop to stop, but leaving a stop to go to cruising speed, you get the best mileage by accelerating briskly up to speed. It's not a jack rabbit start, but faster than most people normally use. That will get the best use of the ICE. When you accelerate slowly, you force a car to inefficiently supply the energy used for acceleration. It takes the same amount of energy to get up to speed either way, so you want to do it as quickly and efficiently as possible.

Tom

 

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Most of the cars I've been in and owned drop into single digits during brisk acceleration. My Corvette did for sure then once up to cruising speed of 70mph is would sit between 27-30mpg.

 

There is a very steep hill with curves at the end of our road. There is a stop sign, so I have to accelerate from a dead stop and I get 6 mpg going up it. I learned very quickly to go down that hill when heading to work and come back into town on a lesser grade. It's the same distance either way. I can't bear to watch the MFD coming up that hill.

 

Yep, that's a perfectly normal experience. The instant mileage is calculated over a very short period of time and shows what you would get if you were to maintain that level of fuel consumption at that speed. Of course, it doesn't end up that way because your consumption rate and speed will vary.

I frequently see single-digit to low teens MPG just starting out, then stabilizing around 50-60 MPG with spikes to 80-99.9+ at cruising speed. The idea is to find the optimal minimum of the former and the optimal maximum of the latter.

- Justifyd