Why do we still have the "Unlimited" speed sign?

A number of members have asked me why can’t we get rid of the “Unlimited” or “National” speed limit sign? Why not have a 60mph or 70mph sign instead.

It is confusing isn’t it? Ever heard of speed zones? There are four zones: national; motorway; urban; and, 20mph. Most people would consider you to be a bit of a sad anorak to know that in Britain there is a convention that if you are in a speed zone there must not be repeater signs and if you are on a road with speed limits only then there must be speed limit repeater signs.
For example, a motorway is a speed zone which has a speed limit of 70mph. There are no repeater signs on motorways (unless a lower speed limit is in force). Upon entering a motorway the “motorway regulations begin” sign assumes you know that the speed limit on motorways is 70mph. As you leave a motorway the “end of motorway regulations” sign assumes that you know the national speed limit is either 60mph or 70 mph. That is why there are not speed limit signs as you exit or enter a motorway (unless a specific speed limit is in force).

Urban areas have two speed zones – a general 30mph speed zone and a more local 20mph speed zone neither of these have repeater signs (again unless another specified speed limit is in force).

Rural areas are in the “national” speed zone. This zone has two speed limits – 60mph for single carriageways and 70mph for dual carriageways. There are no repeater signs here (unless a specific speed limit is in force).

So if you enter a speed zone there are no repeater signs but if you enter a speed limited road there are repeater signs.

This means that if you are in an urban speed zone of 30mph and see a 60mph sign the convention is that you are still in an urban zone but because the road is designed for (and usable at) higher speeds a higher speed limit is set. This speed limit requires repeater 60mph signs.

Similarly, if you are in an urban area and see a 20mph sign you are entering a road with a lower speed limit. This road requires 20mph repeater signs because you are still within the urban (and thus 30mph zone). Do not confuse this with a 20mph zone sign which means that you are leaving the urban zone and entering a 20mph zone and therefore no repeater signs are required.

I hope you have got that!!

If we replaced the diagonal bar “Unlimited” sign with a 60mph sign the convention of speed zones could fall apart. We would then need repeater signs along all of our roads. This would be both unsightly and very costly.

The thinking behind the signing of speed limits needs a total rethink to avoid the increasing complicatedness, confusion and signage.