A docking structure having an electrically conductive cable with a proximal end attached to a retractable cable reel assembly to be secured to a proximal vehicle and a distal end to be attached to a connector on a distal stationary apparatus. The electrically conductive cable runs between a left contact and a right contact. If the proximal vehicle is turned too sharply to the left in attempting to align a connector on the proximal vehicle and a connector on the distal stationary apparatus, a left light connectednulleither with a wire or through a transmitter and receivernullto the left contact, is illuminated. A right light operates similarly. And both lights are illuminated simultaneously when the connectors are properly aligned.