A new interchange to replace a dangerous set of junctions carrying local traffic across the busy dual carriageway of the A12 trunk road near Ipswich in Suffolk is nearing completion. The old crossing forced local traffic to join the A12 and use one of four gaps in the central reservation to cross the road. The new underpass bridge deck was constructed in two halves, closing one carriageway at a time to avoid diverting traffic through the nearby village. Excavation under the bridge will start after both halves of the deck are finished. Reinforced piles will retain earth embankments once excavations are completed. Design was complicated by the need to separate slow local traffic from vehicles entering and leaving the trunk road, and the presence of another interchange some 700m further north. A third lane connects the slip road and the exit road preventing the local traffic from merging with the through traffic. Details are given of the junction layout before and after construction and the reasons for the design changes are discussed. (TRRL)

  • Availability:
  • Corporate Authors:

    Thomas Telford Limited

    London,   United Kingdom 
  • Authors:
    • BOLTON, A
  • Publication Date: 1990-11-15

Media Info

  • Pagination: p. 34-35
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00620092
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1992 12:00AM