European law...
Says that any vehicle over 3.5 tonnes must be speed limited to 90Kph, which is 56mph. It's supposed to be the most fuel efficient speed for the trucks to run at as well as reducing the risks of tyre blowouts. Still bloody annoying when one truck overtakes another on a three lane motorway though.
(Puddle of Sugar was still wallpapering on, Thu 8 Apr 2010, 17:55, 2 replies)

Though some of them....
...have limiters that only kick in after a few seconds. If you're prepared to turn the engine off and on again rather a lot, you can get a big truck up to 80-something. So I hear, anyway.
(sabre-tooth monkey, Thu 8 Apr 2010, 18:24, closed)

No 100 km/h is 56 mph
(frightfullybored, Thu 8 Apr 2010, 19:01, closed)

and its not the Law
(frightfullybored, Thu 8 Apr 2010, 19:10, closed)

*belm*
www.dft.gov.uk/pgr/roadsafety/speedmanagement/vanspeedlimits
The [...] vehicles that are required to have a speed limiter are those which were registered after 30th September 2001 and have a gross design weight of over 3.5 tonnes.

Please shut the fuck up, you're embarrassing yourself.
( Bob Todd whee, Thu 8 Apr 2010, 20:03, closed)

Okay, 'shut the fuck up' was harsh.
It just grinds my gears when people maintain they're correct without bothing to do a simple google search which would show they're wrong.
( Bob Todd whee, Thu 8 Apr 2010, 20:06, closed)

Your calculator's broken
www.google.co.uk/search?hl=en-GB&q=56+mph+in+kph
( Bob Todd whee, Thu 8 Apr 2010, 20:00, closed)