Observations; Presumably running North/South or South/North given that the late afternoon or early morning shadows are at right angles to the road. Given the lack of, and age, of the vehicles I would think it pre-dates the motorways, including the lack of hard shoulder.
Interestingly there are posts either side of each carriageway, not unlike the current motorway marker posts, presumably with reflectors on them.
So my bet, if it is in the Birmingham area, would be the Meridan by-pass as it was known. The collector road has been mentioned but I think it is too old and, from memory, there is only one road bridge over that which is the Water Orton road which crosses it at an angle.