junction 3a was remodeled to give priority to traffic operating between the now westbound section of the m42 and the extended m40 motorway, which opened in stages between december 1989 and january 1991. the section of m42 between the m40 (j3a) and the m5 (j4a) was scheduled to be re-designated as an extension of the m40 at the same time, but this re-designation never took place.