I designed these 1:14 scale traffic lights using RS Design Spark software and this is a set of stl files from that and for for use with e.g. Tamiya trucks. You need some 6 mm brass tube (4x170) for the posts. The rest is 3d printed I used a 0.4mm nozzle with .1 layers but its up to you. I made 4 of these as a set

You will need a controller, LEDs and resistors to complete and I used the Block Signalling TLC2A controller which comes with full instructions. The LEDs will just push in the holes but you do need to solder wires and resistors in place.