Original Hybrid Battery=Drove at speeds of 75-80MPH=The Prius averaged 42.1 MPG-Is this normal?

While it is not great MPG, it seems reasonable considering the speed you were doing. Probably more 80 MPH than 75 MPH, right?

 

I guess it depends on several factors. Is that 42.1 MPG (US)…? If so, that’s 50.63 MPG (UK).
Depends on the air temperature, load in the vehicle, tyre pressures (which makes a humongous difference with the Prius), and whether those were dedicated Low Rolling Resistance tyres or cheap Chinese tyres or similar. Also was the fuel E5, E10 or E15 (assuming the latter exists)?
The 2nd Gen Prius’s 1.5 Litre Atkinson Cycle Engine potentially screaming along the highway at 80 MPH will be running rather inefficiently. Even more so in cold weather and if a series of steep hills are involved in the run. I have reached 95 MPH (UK) in my Prius - but only briefly (to get away from a “crash for cash” scammer who was repeatedly trying to manoeuvre me into crashing into the rear of his tiny euro box filled with 5 passengers - by overtaking me and then brake checking me).
Otherwise I’m doing 65 mph on a motorway (70 mph indicated - but 65 mph on GPS), and I still manage about 60 to 63 MPG (summer).



iPad ? Pro

 

I would have been happy with that number. You were leaning pretty hard on it to hold that speed even on the flats. If you want the impressive MPG drop speed to 65. Frankly there are better metrics to evaluate efficiency of this car which you will learn if it matters.

 

Seemingly so that's what I got on my '09 up until the battery really failed right around 42 43 somewhere in there That's driving the car not the car driving you and usually we were going a lot farther than 104 miles like from Orange county North Carolina to Charlotte and down to South Carolina places like that.

 

what's normal these days?

 

At that highway speed, that MPG is good even for a brand new Gen2. While its EPA highway rating is 45 MPG, the EPA/CAFE test cycle doesn't get up to that high a speed.