I am making a simple board for a project that has two 5 pin screw terminals connected straight through on the board with traces. I have done the calculations for how wide the traces need to be and they end up running into each other. If I use two traces per connection, one top and one bottom can I cut each trace size in half? Is their any rules against this method?
PCB traces handle current the same way as wire does. As long as the overall cross-sectional area is sufficient for the conducting material, you can have as many traces as you like to carry the required current.
However if you’re working to a tight tolerance and one trace burns out, any remaining traces will burn out in a cascade.
I would suggest putting in one trace as wide as you can, and adding a bead of solder along its length to beef it up. A typical trace may only be 100 microns, but a 1mm bead of solder will increase its current carrying capacity 10 fold.