The first time I saw a bed runner was during a stay at a motel not long ago. They are mainly used for decorative purposes, but I suspect that they also protect the foot of the bed and the small size makes them easier to wash than large bedpreads. The dimensions are typically 24" wide and the length is 25"-30" longer than the width of the mattress, so that there is a 12"-15" drop on each side of the bed. I honestly have not seen a lot of these runners in the quilt world, but when my daughter-in-law told me that she had purchased a solid chocolate brown quilt for their new bedroom, I suggested that I make a runner for the foot of the bed to help brighten it up a bit and she loved the idea. I also loved the idea...making a runner is a lot easier than making a full sized quilt!
See a photo of the finished bed runner that I made for my son and daughter-in-law HERE.