Boundary sign designs always present some additional challenges, because you have a lot of freedom to step away from normal rules. Colours, sizes, shapes and fonts can all be varied in 2401, 2402.1 and 2403.1.
The examples shown in the TSRGD have different sized lines of text, have crests/logos added, and even a bulge sticking out of the top border.
2402.1 type A: The simple one line version. This is created in the exact same way as a non-primary sign. Use the heavy text command to add the place name, then use the 1 stack rectangle border to draw the sign border around the place name.
2402.1 type B: This has lines of text that are differently sized. When creating this sign, it is important to consider which text is the normal 8sw high text, which text has been scaled up and if any text is scaled down. Looking closely at the working drawing it becomes clear the 'Welcome to' is the normal sized letters. It is this 'Welcome to' that remains 8sw high and the border size is related to this. The AXTLEY has been scaled up. You can use the Heavy text command to type all three lines of text, and then use the Scale command to scale Axtley up. If you want to scale down the 'Please drive carefully' then use the scale command again. You might want to use the alignment tools and nudge tools to position the three lines perfectly. Then add a 1 stack sign border around them. The detail block x height must also be entered based on the normal sized 8sw text, not the AXTLEY text. For a bit of extra information, you can use the LABELXHEIGHT command to add labels and detail to the various lines of text, which will make your drawing clearer to any manufacturer.
2401: This sign is created in a similar way to the 'type B' above. However the sign shown in the TSRGD has a crest added above the text. If you have a jpg or image of the crest you can use imageattach to add this before you add the rectangular border. It is also possible to just draw a pline or rectangle as a blank box and then write 'crest' or 'tbd' within the box. KeySIGN will happily draw the 1 stack border around either an image or a pline ensure the final design is large enough.
2403.1: This sign has an additional bulge at the top. Currently in KeySIGN the bulge must be added manually, using AutoCAD commands to draw, offset and trim the sign border. You would start by creating the sign without the bulge in a similar way to 2042.1 type B. Create a rectangle border around the sign without the bulge. Draw an arc or arced pline for the bulge. There are no rules about the size and shape so use your best judgement to draw an arc that 'looks rights'. Then explode the rectangle sign borders so that they can be trimmed and filleted together with the arc bulge added. You can join the arc and plines using the PEDIT command. A final detail block can be added using the 'Create or Revise Details' (DDETAIL) command. If you want to colour fill the sign, you should use 'Change border colour' (ChangeBorderColour) command on both the inner and outer sign borders. This will pre-set the colours to be used when doing the colour fill command.