There is an intersection with a traffic light where I live in Golden, Colorado. You can turn both left and right at the light, in addition to proceeding straight.
The road is wide and traffic naturally forms two lanes: left-turners take the left lane and right-turners take the right. That said, the road does not have any formal lines, painted lane indicators, or signs marking the proper lanes for travel.
There have been many times when both I and the driver in the “lane” next to me attempt to go straight despite the road on the other side not being quite wide enough for two cars to pass through at the same time.
To me, taking position in the left “lane” feels correct as I’m not blocking others in the right who wish to turn right on red. I have seen both left-turn-only and right-turn-only lanes at other intersections where only two lanes exist.
Are there any laws or unwritten practices that would dictate proper lane use?