I want to make a regular future journey from north London to near tilbury. the google map direction finder tells me if I go via the north circular its
35 miles and will take 59 min and if I go via the m25 motorway its 47 miles and will take 58 mins.In principle is it more economical ( i.e. petrol consumption ) *generally* to take the higher mileage on a motorway or the shorter mileage on the lesser roads?
Depends entirely on the time of day. If you're travelling towards Dartford Crossing any time in rush hour, you may be quicker using the A13.
I regularly make most of this same journey (amazing coincidence !) The NCR is usually slightly longer time but enough shorter to be a saving in petrol terms, however the M25 is usually less frenetic and almost no need to stop or change gear etc. BUT if the M25 stops it stops for a long time while the NCR keeps going but even slower than normal.
You need to use both routes at the times you need them to decide which is best for you. I prefer the NCR, but my journey is usually during the day, not rush hour.
35 miles one way, or an extra 12 miles the other way to theoretically only save a minute? No brainer, really.
Seriously though, I don't know exactly what google maps bases its timings on, and how much they can vary. Far better to actually mention exactly which part of North London you're travelling from - it's a big place, and where you're getting on the North Circular can make a *huge* difference.
The timings via the NCR will vary hugely according when you're making the journey.
There isn't much 'principle' to it on the basis of the limited information you've given. If you're driving a Jaguar XJ12 in the rush hour the longer route might be more economical. OTOH a Toyota Prius would probably use less fuel on the shorter route, regardless of time of day.
D A Stocks
You're actually asking the question "is it more economical in fuel consumption terms" rather than speed. I would have thought you could arrive at quite a reasonable average by filling the tank (or maybe half filling it) and doing this journey several times, using each route for each (half) tankfull. This presumes you wouldn't use the car for other journeys in the meanwhile.
Rob Graham
I did't realise the fuel consumption was the important bit. If I use the Ferrari the short route (NCR) is the way to save a a fiver per journey, if I use the Lexus then the motorway (longer) is actually cheaper on fuel. (I usually use the metro on the NCR)
It will depend on how you drive and how the car works over the routes various. If you have a conservative style then the shorter the trip, generally, the lower the fuel used.
I have two main commuter routes. One is 37 miles, almost all motorway. The other is 32 miles, a mix of motorway and A-roads.
Using the motorway route and if I'm hypermiling, the Saab typically sees 48 to 50 to the gallon. Call it 49. Using the other route under the same driving conditions and I'll see 43 to 47. Call that 45. Both trips take as near as matters the same amount of time.
In terms of miles per gallon, the motorway route is preferable. In terms of fuel used, call it 3.4 litres for the motorway route and 3.2 litres the other route. I save 0.2 litres taking the shorter route each way. 2 litres a week - not much of a difference.
As has been suggested, giving each alternative a try is the best way.
It really depends how you drive. On the motorway, I'll be trying to get wherever I'm going as quickly as I can, and I'll get 40mpg. OTOH, the other day I had naff all fuel to get somewhere, and trundled along, not making much effort to overtake anyone, for 130 miles on A roads, and managed over
50mpg. You'll struggle to vary fuel consumption by 20% in any kind of traffic, so shorter is the one I'd go for.
As an example, my Volvo will average 19-22 mpg in city traffic and 30-32 mpg on a run, so over 47 miles at 30 mpg I'm going to use 1.5 gallons, and 35 mpg at 21 mpg means I'm going to use 1.6 gallons. Therefore the motorway would be very slightly cheaper in the Volvo.
The P6 averages 15-19 mpg in city traffic and 22-24 on a run, so it'd be cheaper to go through the city in the P6. Around 2 gallons to do the run on the motorway, just over two gallons in the city. No real difference other than avoiding overheating and other old car traits in town.
The Escort should average 32ish in town and maybe 40 on a run, so that'd work out at 1.09 gallons in the city, 1.175 on the motorway.
That is all depending on the motorway being reasonably clear and the city route not being obscenely congested. As it's London, I'd be going by train.
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