Well, I'm sorry to say that generic LEDs won't work well. Until recently, LEDs could not put out enough lumens (candlepower) to be seen under all conditions. In addition, LEDs did not have a wide enough angle of dispersal (you cannot see the light they put out if you are too far to the left/right of the LED). LEDs used in automotive applications are of a special type. You would need to contact an electronics parts house and have them help you select the right LEDs.
I used to do a little design work with LEDs, at that time Stanley LEDs were usually the best in the market.
