Yellow box junction and other markings

Wed, 17 Dec 2025 15:51:41 GMT

I'm trying to find out whether other road markings can or cannot be laid within a yellow box junction marking Diag 1043. For example, lane lines or arrows.

The closest I've got to an answer is in the TSRGD, under "provisions" (S9-8-5) for Diag 1043, which describes the only circumstances in which parts of the marking may be omitted. So, it might be argued that if part of the yellow box was obscured by other markings then it would not conform. What if Diag 1043 was overlaid on top of other markings?

I find it odd that TSRGD doesn't explicitly prohibit the use of other markings whereas the description for a "controlled area" of a crossing tells us "No other signs except..."

In a similar thread a while ago about double-yellow lines through box junction markings, R.Cooper responded that adjudication cases have found that no other markings should be present. But on what basis?

Wed, 17 Dec 2025 17:25:04 GMT

There's nothing much to say either way. There is specific provision for central double white lines to go through a box marking at a level crossing, but for everything else it's down to the judgement of the designer (and adjudicator).

Different road markings often need to co-exist at the same location. Apart from the specific prohibition of most other markings in a ped crossing controlled area, this is generally accepted. The criterion is whether or not the marking will be understood by the average road user and look sufficiently similar to its representation in TSRGD.

I would try to ensure the YBJ marking was 'on top', so that all parts of it were legally present (as you suggest). If the other markings don't then stand out well enough, then it's probably better to omit them.

Wed, 17 Dec 2025 19:15:25 GMT

Most box junction markings aren't all that large. Apart from lane lines, (and "x"s at roundabouts), what other markings might be present? Given the "not large" size of most YBJs, it probably wouldn't be a safety problem to omit any other markings that might otherwise be there and let traffic flow naturally.

You also need to consider that what a designer might put on a drawing may very well not be fully replicated on site. Thus carefully placed "other" markings on the drawing could very easily/inevitably look completely different by the time the lining gang has finished. Is it really worth the trouble to try to ensure an accurate reproduction of the drawing? Especially a year or three down the line when the markings need refreshing.

I agree with Simon, the YBJ should be on top though.

Wed, 17 Dec 2025 19:55:19 GMT

From memory, the adjudication cases were based on the image of the YBJ in TSRGD. As the diagram has no other markings running through it, it was considered (rightly or wrongly) at adjudication that any installed YBJ should also not have any other markings running through it to be enforceable.

Of course if the yellow box isn’t to be enforced then it is less important and there is more room for engineering judgement. Any YBJ should be designed to be as small as possible, and only cover the area tracked by conflicting vehicles (not the entire junction area), making additional markings within it often unnecessary.