maps - Multi colored strokes in Illustrator?

I'm drawing maps in Illustrator. Our way of depicting divided highways is parallel lines with a fill. Here is an example:

The way I did this was a 1 point yellow stroke, command c, command f, send to back, explained stroke to 2 points and make black.

These are a pain to make and edit. I'm wondering if there's a way to do this with a single stroke.