Do you want to know how it's done? Learn how to use Photoshop the easy way!
This is a great way to create a "road" style to apply to a path. Once you create this style, all you have to do is make a path with your pen tool and apply the style you created and you have instant road!
Create a new file of your choice in size. This style doesn't require a huge canvas. Select the pen tool and make a stroke.
Open the appearance palette by selecting Window/Appearance from the file menu. Also make sure that the stroke palette is open by selecting Window/Stroke from the file menu. In the stroke palette change the weight to 10pt.
Drag the 10pt stroke from the appearance palette to the Duplicate Selected Item icon at the bottom of the palette. This will create a copy of the 10pt stroke so that there are now two of them.
Double click on the stroke tile and drag the cursor to the white area to make the stroke at the top of the heap white. Go back to the stroke palette and change the weight of this this white stroke to 1pt. This should give you a white stripe through the middle of the black stroke that we started with as shown below.
Go back to the stroke palette and put a check in the dashed lines box. In the first dash box type 6pt and press enter.
You should end up with the sample below.
OK now we have our road style created. Click on the New Graphic Style button in the graphic styles palette and your road will be saved in this document as a style.
Double click on the new style and name it "Road".
Now whenever we create a stroke in this document, we can add this style to it by clicking on the Graphic Style button we made.
Save the document. I will save it as "Road Tutorial". To access this style from a new document, select Window/Graphic Style Libraries/Other Library... and navigate to your "Road Tutorial" file you saved and double click it, and a new window will pop up with your road style in it.