You are going to get different responses depending upon the era, location, big city versus town or village, etc.
On my layout, I model dowtown Chicago in the mid-50s. I use 1/8" automobile pin striping on 0.010" styrene sheet. My main streets are 6" wide and my secondary streets are 4" wide.
Here is a sample of my urban streets.
Rich
Alton Junction
I didn't want to hijack the other street thread so I thought I should start a different one for this topic.
What are your tricks for putting lines on urban streets and how far do you go? Simple white dashes or full blown double yellow lines and marked off intersection markings?
Rick