38 mpg on trip from LA to Miami in a 2010 Prius IV - 107k Miles

You have to drive no more than 50mph all the time in order to get 60-70 mpg.

 

This is steady state cruising on flat ground with no wind.

With acceleration to get to speed and an impatient attitude you could average 38 MPH

 

38MPG at 80MPH isn't bad. I got 39MPG with the cruise set at 75 with hills and wind. You should get over 40MPG in just about any other driving situation. Pulse and glide takes practice to perform, especially in traffic, but sometimes you have to just go with the flow.
I don't know why you would get rid of it for a Civic. If you're getting bad mileage now, you'll still get bad mileage in a Civic compared to average. Your Prius should get about 5MPG more on the highway and 10-15 more in city.

 

Tire pressure , I run 42 front 40 rear , slow down a bit , were the temperatures low
During your trip ? The prius doesn't like cold temps , milage will,go down
Did I mention , slow down a bit

 

Do you have Low Rolling Resistance Tires? Also as Bingee said Tire Pressure. When its cold, block part of the grill. Little easier on the gas. I can get 58mpg on a long run at 65-68mph. (Fairly Flat Terrain, Temps above 45 degrees).

 

Are the new tyres of exactly the same type and are they on the front or the back?

 

That curve does not get real ugly until 75 MPH, can you drive 72?

 

If your driving the Prius like a regular car and not pulsing and gliding you can forget it. It takes some effort on your part to exceed the 50+ mpg's mark.

 

Hopefully your buddy put the right oil in the car. That, along with the other things mentioned above, could make some difference. We're also in winter blend gas which will have an impact.

I just did a trip from Cincinnati to Louisville and back a couple of weeks ago. It is a very hilly drive. In addition to the cold weather, it was heavy rain one way (kills MPG). My highway speed was about 65-75 MPH. I averaged 48 MPG on my trip (+ a few days of some regular short distance driving).

You CAN get the higher MPG others are quoting (especially if you live in flat & warm Florida), but it may take some effort. What I did when I first bought my Prius was to spend a tank or two to learn to drive the car efficiently and get good MPG. This is learning to use the HSI and P&G and other techniques. After awhile it becomes a bit natural and you learn to drive more by feel and less by focusing on the HSI. I don't drive it like a grandpa anymore, nor do I drive it like I stole it (but I occasionally have some fun in Power mode). I have managed to average 49 MPG in a cold climate with hills and some very short trips.

 

The 50 MPG rating is under EPA testing, not normal driving. So nothing wrong with advertizing the EPA result and it is legal.
The 450 hp Stang will get you 16 MPG EPA.

 

I am actually amazed at how close the car gets to the estimated 49 MPG if you look at real world experience: 2010 Toyota Prius MPG Reports | Fuelly. Your MPG is at the far end of the bell curve.

What really makes the Prius spectacular from an MPG point of view is that it's technology does things to take a lot of the human variables out of the equation. External conditions and extreme driving (on both sides) can still have an impact though (~+/- 10 MPG).

 

No car is marketed with any MPG in the US except what the EPA got. (driving like the EPA does)

No car you buy will get EPA numbers driven as you drive. As you commented on, many Prius drivers exceed the EPA numbers, they simply drive better than the EPA does.

The Prius does very well at getting the same real world MPG on fuelly.com as the EPA did. (It is possible that most Prius drivers DO drive like the EPA) I would compare Fuelly.com numbers to EPA numbers for any car you are interested in.

No car can make driving like a maniac fuel efficient, even if you 'normally' drive like a maniac.

 

I have never failed to beat the EPA mileage numbers just by driving "normally". Normally to me means I accelerate briskly, but look ahead to see what traffic and signal lights are doing. It also means I don't care if people pass me in their attempt to win the race to the red light.

Normal people drive stupid. Most of the hybrid tech in the Prius is designed to merely offset this stupid driving. If I had the Prius without the electric motor and a manual gearbox, I'd probably get fairly close to the same MPG as driving one with the hybrid system.

As others have stated, no car will get 50MPG at 80MPH. The power required to sustain speed increases with the square of the speed. That means it takes exponentially more power to go just a little faster.

 

Actually, I think my Insight would be able to.

What mileage do you usually get? The only number you gave was for the trip you took, what does your regular driving get you?

 

You can get 50+mpg at freeway speeds, but not in cruise control. As noted, you have to work at it. You can also get 60+mpg on surface roads, but again, you have to work at it.

 

Actually, while acknowledging driving conditions here are quite different, I have a long term average of 49+ US gallons and often achieve 51+ US gallons while using cruise control 90% of the time. I just let the car do it's thing.

I also don't drive at much more than 68 MPH (110 KM/H) highway speed.

 

I have to drive 57 miles each way once a week. Mostly highway, at 77MPH for half the distance and then 67MPH the other half. I set the cruise and go. At the end of the trip I get 52.5mpg going south and 47.5 going north (on avg.). Temps are cooler when I leave and warmer on the trip back. My GenII used to get slightly better mileage... This is with ground effects and 17" low profile tires. Maybe you should try cruise control. You may be holding the pedal down farther then you need to, thus wasting gas. Try it!