In a lot of the tracks i've been playing i've seen these extremely helpful billboards which point in the direction you need to go. Blue for down, green for left and right and i think i saw a red 'not this way!' cross. In my infinite noob-dom, i'm wondering where these come from/how to put them in my own tracks? Are they actually in the game already, or is it a mod?

Apologies if this has already been asked, couldn't find a search funtion on this forum?

Anyway, thanks in advance for any help

P.S
I'm new, so Hello!

In the track editor there is a paint bucket tool on the toolbar. Press it then click the sign you want to edit and then it gives you a list of signs to choose from.

Excellent, thank you very much

while were at it, What's the biggest possible resolution for those billboards?

Vii says:
while were at it, What's the biggest possible resolution for those billboards?

The sky's the limit I guess, though practically it would be 800w x 400h.