Motorway reflective stud placement. Motorway or dual carriageway reflective studs (or cat’s eyes as they are also referred to) are designed to be most effective in poor light conditions by reflecting light back to the driver to signify which part of the motorway they are driving on, or where they might need to exit. The colour of the studs always has the same placement on motorways and dual carriageways. Questions relating to reflective road studs are often asked during the theory test.