6 volt directional bulb

[Synchro909]

Originally Posted by Charlie Stephens

I hope your turn signals are wired to use the brake light bulb as the turn signal. If they aren't wired that way the brake light will wash out the turn signal.

Charlie Stephens

Using the brake light as the turn signal was banned here back in the mid 1950s. When they introduced it on one of their cars, GM was met with condemnation by buyers. Bad move!
When I have been driving in the US I found the system there very confusing. It also depends on when you glance at a car whether the brake lights are on or one is out of action. Here, turn signals front and back must be amber in colour leaving no room for confusion.
Back to the OP. I was going to suggest LEDs but I understand the problem of directionality. Maybe you paint the inside of the light white and face the LED globe backwards so that the light going through the lens appears to come from the whole of the body. I know a guy who did that with his brake light shining on the pale coloured back of hi scar. The whole back glowed red - an interesting but maybe not legal idea.