On Sun, 11 Jul 2010 00:56:01 +0100, Steve Firth wrote:

I generally drive at the legal limit, using cruise control. This means
that my longer journeys take 16 hours of driving. If I drove at 56 mph
it would add eight hours to my driving time.

Your ability to do maths is a bit suspect.

I suspect yours is:

16 hrs @ 70mph = 1120 miles

1120 miles @ 56 mph is 20 hrs.

20 - 16 = 4 extra hours.

I generally set the cruise at 62 ish mph, fast enough to get past the
heavies at a reasonable pace, not so fast the the motor is reving a
bit quicker than it's really sounds happy at.

--
Cheers
Dave.