Speedos and other things

[tonyidle]

In the UK they are every tenth of a mile (176 yards).

I have vague memories of markings in furlongs (eighths of a mile) and measuring in chainage for tarmac laying (10 chains = 1 furlong). No doubt they'll be back after March next year.

Only until around 1980.

 

[tonyidle]

I think the most accurate method is doing a constant speed as seen on the speedometer, using mile markers and a stopwatch to calculate actual speed.

Possibly true if using a cruise control - but not much use for a quick check.

 

[Beemobile]

My Sat nav is set to remind me of the speed limit but its always less than the Speedo on vehicle, so if I get caught on a speed camera doing 33miles an hr in a thirty mile limit, and the Sat nav says 30 miles an hr do I have a case to argue, I guess not, but I'm sure someone will confirm that for me.

 

[john lillie]

I have often gone past speed cameras virtually on the limit according to my satnav, never had a problem, so far.....

 

[autorouter]

Only until around 1980.

Yes you're right. I checked yesterday on the motorway and the markers were kilometres, and every 100 metres.

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[tonyidle]

My Sat nav is set to remind me of the speed limit but its always less than the Speedo on vehicle, so if I get caught on a speed camera doing 33miles an hr in a thirty mile limit, and the Sat nav says 30 miles an hr do I have a case to argue, I guess not, but I'm sure someone will confirm that for me.

If your speedo isn't over-reading by 3mph at a genuine 30mph I suspect it's faulty . On a more serious note it is worth knowing your speedo error. I can't be the only driver forced to follow someone in a roadworks 50 at no more than 45 because the man in front believes his speedo. I'm relaxed about the speed others travel at, for the most part, but I really object to travelling under the endless 50s that afflict our motorways.

 

[Tony50]

The Law in the Uk use to be that Vehicles by the said Law had to have a speedo reading that is accurate upto and including 30 MPH.

 

[tonyidle]

The Law in the Uk use to be that Vehicles by the said Law had to have a speedo reading that is accurate upto and including 30 MPH.

"The UK law is based on the EU standard, with some minor changes. A speedo must never show less than the actual speed, and must never show more than 110% of actual speed + 6.25mph. So if your true speed is 40mph, your speedo could legally be reading up to 50.25mph but never less than 40mph.19 Sep 2012"