Know this is an older post,
But what we use is reflective material, cut to the shape of a rectangle then with little rectangle inserts they're placed in and into the side of the runway. No mistaking if for a parking lot, and they REALLY light up the edge during dusk and at night. Pictured below is just a simple shot from a flash on a camera, and as you can see they light up quite well.
http://imgur.com/hPG4NxL
http://imgur.com/ouOmmvF
