Most vehicles on that Hiway would be pickups and larger, would they not? Their line of sight is over top of your tailgate and higher. You are going the wrong way with additional lumination. Whatever kicks up, dust, dirt, snow, mud...as your driving will tend to obscure low down lights like you have. Tape will bake on and never come off and not look good on your truck. LED good idea and actual LED's in the bed roll would be custom, safer and good height. There are two good post on those, search "bed roll lights".
