What do the red circles on the backs of lorries signify?

[SurreyGuy]

Does anyone know the meaning/function of the red circles with black numbers in them that appear on the backs of lorries?

At first I thought it was "this vehicle is limited to xx m.ph.", but I am seeing lots of lorries with up to three stickers lately, so maybe it can't be that?

T.I.A.

[sddsddean]

Its for trucks that run in Italy. For some reason I have never been able to fathom, trucks on Italian roads have to display 50, 80 and 90 kph stickers. Luckily I never went there, so didn't have to have them on!

[Ethel]

You even need a speed limit sticker to drive a lorry in the Isle of Man.

http://www.gov.im/lib/news/transport/transport publicn172.xml

The daftness of having different speed limit stickers is to meet the different speed laws of varying countries.

The problem is obvious - which sticker applies at any given time?

[SurreyGuy]

Thanks - all remarks agreed with! :o)

[bazmoore]

hgvs are subject to speed limits 60mph motorway
50mph dual carriageway
40mph single carriageway
these limits are shown on the rear of continental lorries in kph

baz