A vehicle article carrier system having at least one single side releasable cross bar. The cross bar includes end support assemblies at opposite ends thereof. Each end support assembly includes a pivotally mounted locking member which can be locked and unlocked relative to an associated side rail. Both of the locking members can be locked and unlocked by a user manually engaging one of the locking members and pivotally moving it into an unlocked position. This causes simultaneous pivoting movement of the locking member at the opposite end of the cross bar so that both the locking members are simultaneously locked and unlocked from their respective side rails. When in the unlocked position, the cross bar can be lifted directly off of the side rails, thus eliminating the need for any disassembly of the side rails when the user desires to remove the cross bar entirely from the side rails.