Motorway mpg

I assume that's normal MPG (not USA galleons?).

I did a longer run the other day - 275km return, but it was quite congested one direction, so a lot was slower, and I got 80(UK)MPG, using RADAR Cruise the whole way and back, and that included going through the city on the return.

I do a 25km commute (plus return) 3 or 4 times a week, and get between 68 and 72(UK)MPG. But if I'm just puddling around my suburb with little short intervals between stops at various shops etc, it might get down below 60(UK)MPG.

I had a FIESTA Diesel (Manual) before this - and it averaged 59.7(UK)MPG over 60,000km - and PRIUS is appreciably bigger.

Prior to that, I had a FOCUS Diesel (2litre Manual) which averaged 52MPG over 60,000km. My commutes in all 3 cars are similar, and I guess my driving is too.

My average over 25,000km is 68.2(UK)MPG in the PRIUS - with 15" rims.

 

Your cruising speed on the motorway will be crucial to the fuel consumption. Best economical speed is 50-55mph. Over that and it will impact on the mileage. I cruise the M5 at 70mph an get around 55-60mpg, but going faster than that and it falls off dramatically. I would say, you won't be disappointed if you keep it under 71mph.

 

Actually, it might be a bit quieter than the diesel, but your mileage does improve if you learn to lift your right foot whenever possible. You don't get the same engine braking in a Prius as strongly as you get now. I still use the heavy boot occasionally for fun, but it only pulls the mpg down for a while and is not a major impact on fuel.
Edit: Unless you do it all the time!

 

A light touch on the brake uses regenerative braking to use the stopping energy to recharge the battery rather than converting to heat.
A harder touch activates the normal friction brakes.

 

it's all about speed, not which road you are on. it is possible that the prius won't be quite as good as a diesel, depending on the diesel.
also, the prius gauge is optimistic, and you will find the calculation at the pump a bit disappointing.

 

I was trying to differentiate between the ICE drag and the Prius drag on lifting off the accelerator, not involve regeneration.

 

A 240 mile round trip on mostly motorways last spring showed me 66 mpg on the trip. Cruise was set to 77 mph (to allow for the 10% built in speedo error), most of the way, with the exception of a couple of 50 mph road works with average speed cameras where I set it to 55 mph.
As RCO says above the lower the cruising speed the better the mpg. I'm pretty sure if I had travelled the whole journey at 55 mph I'd have seen well over 70 mpg on the trip (just before I fell asleep). I've done 90 mile journeys to the coast, wholly on A roads, keeping up with the traffic and speed limits and seen around 80 mpg on the trip.

 

You old enough to nap at the wheel???

 

Yes, 65 in April, I find the Gen 4 is so easy and less stressful to drive that I have to prop my eyelids up with matchsticks so's I don't fall asleep at lower speeds (don't you just love adaptive cruise and LKA when you're asleep)

 

Unfortunately, we do not have LKA (Lane Keep Assist). Toyota replaced it with the less capable LDA (Lane Departure Alert). I believe that may be true for you too. Some older Prius models had LKA.

 

My bad, LDA wakes me up enough though.

 

THIS.
And the MPG shown by the onboard computer usually isn't accurate; it usually err's a bit on the high side.

 

The accuracy, while potentially beneficial, it is not as useful as the variation in averages - however measured - so long as the measurement equipment is a constant.

 

Mine seems to be consistently 5 mpg out on the trip compared to tank to tank calculated mpg.

 

The one tank I calculated, the car was about 10% high.

 

That's too kind. More like "invariably biased".

 

Yes, I think they all err on the optimistic side (KIA and FORD were similar) - it's a calculated figure from various inputs. Mine has varied between 4 and 8%.