M6 Junction 4
Junction 4 started out on opening in July 1971 as the junction with the A446 on the east of Birmingham, southbound it was the junction for Solihull and west Coventry, northbound the junction for Coleshill. The junction was a roundabout over the M6 the commonest and safest type of junction on the M6 as shown below:-
In 1985 the M42 was extended up the east side of Birmingham to run parallel with the A446, in order to provide a southern interchange with the M42 junction 4 was extended and used in conjunction with junction 4a to facilitate movement between the two motorways the resulting junction is shown below:-
From the M6 northbound the M42 Southbound could be reached, whilst from the M42 northbound the M6 northbound and M6 southbound could be reached, however with Junction 4a these two junctions now formed a complete interchange between the two motorways. With thanks to Nic for the photos
