Adding roads in a modern, "google-maps"-esque style

[NedS298]

Hey everyone, I just need some help adding roads to a map I've been working on briefly amongst others for a while; my question is - how do I go about it? I've been using Photoshop but I've also got access to Illustrator, if it helps.
Here it is:

Island.png

[Hai-Etlik]

Roads on modern maps tend to be represented as "cased" lines. Draw the same lines on two layers, the bottom slightly thicker than the top and you'll get a line with borders. Note that this should not be done on a per-line basis or intersections will look screwy. Usually the casing will be consistent, not proportional to the width of the line. A 2mm line and a 1mm line might both have 0.5mm of casing -- the lines underneath would be 3mm (2+2*0.5) and 2mm (1+2*0.5) -- rather than 0.5 and 0.25 respectively.

If you use a dashed line on top of a solid one, you get a symbol widely used for railroads.

[NedS298]

thanks, that cleared it up