Back in '92, I used to get a consistent 40mpg on a 400 mile round trip to Plymouth, constant 75 mph indicated, 1/2 mile to motorway one end and 1 mile from dual-carriageway at the other - that was a Cavalier 2.0 GLi pre-cat.

Now, I've got no chance of cruising at constant speed on that journey now !

Any one can add whatever figure they want to HJ real MPG so i ignore it.

Try this link you can play with driving style inputs.

Google whatcar true mpg its more accurate and you can adjust your driving style, i posted a link but it was blocked.

Edited by xtrailman on 03/01/2015 at 18:49

The at-the-pump economy figures for my last 4 company cars, on tankfuls that have involved around 75% motorway driving are below. Traffic permitting, I usually set the cruise control at an indicated 80, and will look to quickly regain this speed when traffic allows.

2003 Passat B5.5 PD130 manual (6 speed) saloon: between 50 and 52mpg. Overall mpg in my ownership was 46.25 over 5 and half years and 68,000 miles.

2008 Mondeo IV 2.0TDCI manual estate: between 45 and 47mpg. Overall mpg in 3.5 years and 38,000 miles was 42.5.

2011 Volvo V60 D3 (163bhp) manual: between 50 and 53mpg. Overall mpg in 3 years and 39,000 miles was 46.5.

2014 Volvo V60 D4 manual: between 50 and 52mpg.

In my experience, none of these cars gave significantly greater economy (i.e. no more than 1 - 2mpg at the pump) by sticking to 70 / 75 mph over the duration of a long motorway journey.

Drive a Toyota Auris hybrid - just coming up to three years old and have full brim-to-brim records since purchase (sad!). The majority (probably 80%) of my driving is on Spanish motorways usually on cruise control at 110kph (68mph). Over the period I've averaged 5.1 l/100km (55.1 mpg):

Link to fuelly website:

www.fuelly.com/car/toyota/auris/2012/cuius/106408

Click on "UK" top left to convert to imperial units if it's showing metric

Sadly retentive of information like this; this post was made for me!

My regular commute in my IS300 is 56 miles per day, split 3.6:1 in ratio of motorway miles:urban roads. I drive earlyish in the morning and lateish in the evening, both against the major flow of traffic so I can use cruise control probably for 80% of my motorway time while my urban is limited to four sets of traffic lights, some 30, some 40 and some 50mph limit. Generally I’ll stick my cruise at an indicated 70 to 72mph (so around 65mph true speed) which is 2500rpm roughly. This gives me at this time of year a four fill (95RON) rolling average of 31.0mpg, which rises to 33.0mpg in summer. Last winter was clearly colder than this (so far!) as it fell to a rolling average of 28mpg. Over the last 28k, average overall has been 31.1mpg; there have been longer trips in there of course, but also much schlepping round town as the family taxi!

Interestingly (I can’t believe I’m so sad as to be writing this…) if I take the official Urban and Extra Urban for my car and apply the 3.6:1 ratio it come out at 31.7mpg, which is surprisingly close. Then again, my IS predates the current slight-of-hand tweaks performed by manufacturers specifically to achieve lowest possible emissions across their range…

My previous motor over the same sort of driving averaged 42.5mpg over 87k. Again, apply my 3.6:1 to the Urban and Extra Urban I get a predicted 44.6mpg, which is quite a bit over. It was a ‘lean-burn’ engine with 59% of the cubic capacity of my current car, and a manual as opposed to an automatic.

Make of that lot what you will!

Sad git that I am, I actually keep a record of my car's mpg (not from the trip computer - only using fuel bought and odometer from mostly brim-to-brim fill ups).

My Mazda3 mk1 1.6 petrol does about 44mpg on longer journeys on dual carriageways/motorways (a good 280+ miles on such roads to annual holidays in Cornwall as a good guide) in reasonably weather/without significant hold-ups; it does about 33-35mpg in slow-moving traffic, such as in built-up areas.

My overall average is (and given on the True mpg data) about 40.5mpg (range from 38-42mpg depending upon where I'm working), I would say about 2/3rds on dual carriageways/motorways or fast-moving single lane roads, plus I generally drive with a lighter foot than most people, though not always (the occasional 'Italian tune-up').

Still, better than the claimed mpg (that given in the original sales literature - the figures on this website are for the 2006 update version [reduced power/increased 0-60 time/reduced CO2], not the original 2004 engine specs, which are I think about 37-38mpg [combined] for the 1.6 petrol).

I would suspect that most petrol cars will have about 30% better mpg for motorway (legal speeds!) as ooposed to in-town driving; for diesel the gap may be a bit lower. Besides the percentages of town/motorway type driving, I think that the actual mileage driven per trip makes a huge difference - I know of a lot of people who get very poor mpg because, unsurprisingly, they do lots of short journeys, which is very common these days, especially for families with the second car as the local runaround.

Many people are still (daftly in my view) buying small, diesel-engined cars for just 'popping to the shops', thinking that the high (EU) 'tested' mpg will easily save more money over the ownership of the car than the extra cost over the petrol-engined equivalent. Sorry guys, but they won't (and will likely be the cause of future engine problems) as they don't have enough time to warm up (not that I'm an expert, but do know that diesel engines are more thermodynamically efficient than petrol ones, so take a lot longer to get up to optimum temperature) to get the full mpg potential.

If you do mainly short jouneys (whatever the mileage), less than 20k miles p.a. or don't need to lug very heavy loads (trailers, building materials etc), then always go for a petrol engined car. The only real choice is for those (e.g. taxi drivers) who do large in-town mileages (a decent mileage per day with very short stops [probably without turning the engine off]), who could chose either diesel or petrol hybrids (depending on location - congestion charge fees etc).

Skoda Octavia 1.4 Tsi

46-47mpg on motorways at 70-75mph. Have done 51mpg on long A Rd trip to Skye and back at 50-60mph.

I am looking to update my car and have a few different options.

My driving is 80% motorway, and although i've seen the data in 'real mpg' it does not tell you the way in which the vehicle is driven.

Has anyone had a motorway journey (speeds of 65-80) and measured the brim to brim mpg? If so - could you please post your findings, along with what you drive

I drive a 2014 1.6 CDTI 110 Vauxhall Astra;

My commute is fairly free from traffic, 2 miles urban, 12 miles dual carrageway, 27 miles motorway followed by 3 miles rural.

I was curious so I did the following;

1 X tank brim to brim at an indicated 75 mpg is 61.2 mpg

1x tank brim to brim at an indicated 60 mpg 78.7mpg

Anicdotally the OBC shows 99 Mpg flat and level at 60mph

82 flant and level @ 65mpg

Driven 'normally' I average 67.7 according to my spreadsheet. The cars OBC seems to be 4.2 MPG optimistic. Not the fastest thing on the planet, but strangly economical, I'm plesently surprised!

Edited by GHSAUNDERS40 on 09/01/2015 at 19:00