RogerBW's Blog

Red and amber filters 09 September 2017

There is a practice common to the road systems of many countries which we don't use in the UK. Why not?

We have traffic lights that show red, amber and/or green. We also have green filter arrows that take priority over a red light, so that you can have most of the traffic stopped, but the traffic that's leaving the junction in a particular direction allowed to proceed (most often, a right-turn filter off a main road, where the main traffic is stopped so that other vehicles can turn across it).

But sometimes one wants the reverse situation: everything is allowed to proceed except for one direction. This is done with a red light, and one or more arrows for the directions that are allowed to continue. So one gets a situation like this:

Google Street View image

of coming round a corner and seeing a red light ahead. But in fact that red light only applies to the right turn, and as you get closer you'll see the green "straight on" filter:

Google Street View image

There used to be a similar isolated green arrow at the split of the A1 and A406 westbound from Henly's Corner; that's now been "fixed" by dividing the road further back.

This is silly. And there is a better way. In continental Europe, and Australia, and I believe even the US where mostly driving is kept as simple as possible, they also have red and amber filters. (The European ones are a dark arrow silhouette over a normal traffic light; I believe the American ones are an illuminated arrow like the green filter.) Just as with the green arrow, they take priority over the general signal. So in the case above, you'd have a normal green light and a red arrow indicating that right turns are not allowed.

Why can't we have these? Are British drivers considered uniquely stupid?


  1. Posted by chris bell at 11:33am on 09 September 2017

    So we all have to learn a whole new set of stuff and while we are learning, there are a lot of shunts. These are a nuisance and may even be painful and/or expensive...

    In your example, the only drawback is that some people may drive slightly more slowly for a very short distance, and arrive at their destination two seconds later than they would have done. Oh dear.

    (I think it may even have been you who pointed out to me, about overtaking because you are in a hurry, that one very rarely has reason seriously to regret not doing it and not doing it is unlikely to have life-changing results, but one quite often does get into trouble if one overtakes when it may not be quite safe.)

    The answer is probably best summed up with "It works, don't fix it."

  2. Posted by RogerBW at 11:46am on 09 September 2017

    But it works in lots of other places with red/amber filters, and they don't seem to have problems with it. I don't even believe that British drivers in mainland Europe get confused by this system.

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