[Espeefan]

Rubber is hard to work with. You could always try some tire paint pens (used for coloring the raised lettering and sidewalls) and draw the lines with that, or just try some regular spray paint in a can. Mask off your lines, and go to town. The only thing is rubber flexes a lot, and I wouldn't be surprised if the paint cracks and peels off after time. If you could find a way to super glue (they have special glue just for rubber) some yellow or white strips of thin cut rubber down to the road, that might work too. Who knows.....maybe you could just draw the lines on with some chalk. Eventually it would come off too, or fade, but it would be no big deal to touch it up. Mistakes could be washed off.