Marylands Interchange
| Marylands Interchange | |||
| Location Map ( geo) | |||
 | |||
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| Location | |||
| Mountnessing | |||
| County | |||
| Essex | |||
| Highway Authority | |||
| National Highways | |||
| Junction Type | |||
| Roundabout Interchange | |||
| Roads Joined | |||
| A12, A1023, B1002 | |||
| Junctions related to the A1023 | |||
| Junctions related to the B1002 | |||
Marylands Interchange is junction 12 of the A12. On the ground signage on the A1023 and B1002 refers to it as Mountnessing Roundabout
History
The junction opened in 1965 as the northern end of the Brentwood Bypass. It originally was an at-grade roundabout with flaring on the western side for an underpass to allow the dual carriageway to continue in the future, and the flaring was used when the Mountnessing bypass was built in 1973.
During the early 1970s a new airport was planned at Maplin and several routes for a motorway connecting the airport with London were studied. One of these would have passed near Marylands Interchange and the junction would have been dramatically altered to cater for the new road. However, the airport proposals were scrapped soon afterwards.
Routes
| Route | To | Notes |
| London | ||
| Colchester, Chelmsford | ||
| Shenfield, Brentwood, Billericay (A129) | ||
| Mountnessing, Ingatestone | ||
| London | ||
| Southend, Maplin Airport |