- M4 between J49 and J48, Carmarthenshire (Grid ref SN573067)
- M4 between J48 and Carmarthenshire boundary, Carmarthenshire (Grid ref SN580029)
- M4 between Swansea boundary and J47, Swansea (Grid ref SN592025)
- M4 between J47 and J46, Swansea (Grid ref SS631992)
- M4 between J46 and J45, Swansea (Grid ref SS653993)
- M4 between J45 and J44, Swansea (Grid ref SS689990)
- M4 between J44 and Swansea boundary, Swansea (Grid ref SS705973)
- M4 between Neath Port Talbot boundary and J43, Neath Port Talbot (Grid ref SS720967)
- M4 between J43 and J42 western spur, Neath Port Talbot (Grid ref SS724955)
- M4 between J42 western spur and J42 eastern spur, Neath Port Talbot (Grid ref SS727950)
- M4 between A483 and M4 (42) main carriageway, Neath Port Talbot (Grid ref SS729940)
- M4 between M4 (42) main carriageway and A48/A483, Neath Port Talbot (Grid ref SS729945)
- M4 between J42 eastern spur and J41 mid-junction, Neath Port Talbot (Grid ref SS746923)
- M4 between J41 main carriageway mid-junction and A4241/A48, Neath Port Talbot (Grid ref SS749922)
- M4 between J41 mid-junction and J40, Neath Port Talbot (Grid ref SS769902)
- M4 between J40 and J39, Neath Port Talbot (Grid ref SS784880)
- M4 between M4 Junction 40 and M4 Junction 39, Neath Port Talbot (Grid ref SS784880)
- M4 between Roundabout and M4 Junction 39, Neath Port Talbot (Grid ref SS789871)
- M4 between J39 and J38, Neath Port Talbot (Grid ref SS792867)
- M4 between M4 Junction 39 and M4 Junction 38, Neath Port Talbot (Grid ref SS792867)
- M4 between J38 and Neath Port Talbot boundary, Neath Port Talbot (Grid ref SS800844)
- M4 between Bridgend boundary and J37, Bridgend (Grid ref SS807821)
- M4 between J37 and J36, Bridgend (Grid ref SS900828)
- M4 between J36 and J35, Bridgend (Grid ref SS942819)
- M4 between J35 and Rhondda, Cynon, Taff boundary, Rhondda, Cynon, Taff (Grid ref ST028805)
- M4 between The Vale of Glamorgan boundary and J34, The Vale of Glamorgan (Grid ref ST057799)
- M4 between J34 and J33, The Vale of Glamorgan (Grid ref ST071796)
- M4 between J33 and J32, Cardiff (Grid ref ST100799)
- M4 between J32 and J30, Cardiff (Grid ref ST200836)
- M4 between J30 and Cardiff boundary, Cardiff (Grid ref ST225830)
- M4 between Newport boundary and J29, Newport (Grid ref ST240838)
- M4 between J29 and J28, Newport (Grid ref ST267843)
- M4 between J28 and J27, Newport (Grid ref ST285870)
- M4 between J27 and J26, Newport (Grid ref ST300893)
- M4 between J26 and J25A, Newport (Grid ref ST309898)
- M4 between J25a and J25, Newport (Grid ref ST320899)
- M4 between J25 and J24, Newport (Grid ref ST350893)
- M4 between J24 and Newport boundary, Newport (Grid ref ST391892)
- M4 between Monmouthshire boundary and J23A, Monmouthshire (Grid ref ST417880)
- M4 between J23A and J23, Monmouthshire (Grid ref ST431878)
- M4 between J23 and Monmouthshire boundary, Monmouthshire (Grid ref ST480872)
- M4 between South Gloucestershire boundary and J22, South Gloucestershire (Grid ref ST526860)
- M4 between J22 and J21, South Gloucestershire (Grid ref ST580865)
- M4 between J21 and J20 / M5, South Gloucestershire (Grid ref ST610850)
- M4 between M5 (20) and J19, South Gloucestershire (Grid ref ST631815)
- M4 between J19 and J18, South Gloucestershire (Grid ref ST700777)
- M4 between J18 and South Gloucestershire boundary, South Gloucestershire (Grid ref ST780785)
- M4 between Wiltshire boundary and J17, Wiltshire (Grid ref ST892790)
- M4 between J17 and J16, Wiltshire (Grid ref SU015826)
- M4 between J16 and Wiltshire boundary, Wiltshire (Grid ref SU107827)
- M4 between Swindon boundary and J15, Swindon (Grid ref SU155819)
- M4 between J15 and Swindon boundary, Swindon (Grid ref SU220809)
- M4 between Wiltshire boundary and Wiltshire boundary, Wiltshire (Grid ref SU258794)
- M4 between West Berkshire boundary and J14, West Berkshire (Grid ref SU324750)
- M4 between J14 and J13, West Berkshire (Grid ref SU416726)
- M4 between J13 and J12, West Berkshire (Grid ref SU493733)
- M4 between J12 and West Berkshire boundary, West Berkshire (Grid ref SU680696)
- M4 between Wokingham boundary and Wokingham boundary, Wokingham (Grid ref SU705692)
- M4 between Reading boundary and J11, Reading (Grid ref SU713687)
- M4 between J11 and Reading boundary, Reading (Grid ref SU718686)
- M4 between Wokingham boundary and J10, Wokingham (Grid ref SU750696)
- M4 between J10 and Wokingham boundary, Wokingham (Grid ref SU810717)
- M4 between Windsor and Maidenhead boundary and Windsor and Maidenhead boundary, Windsor and Maidenhead (Grid ref SU833735)
- M4 between Bracknell Forest boundary and Bracknell Forest boundary, Bracknell Forest (Grid ref SU849747)
- M4 between Windsor and Maidenhead boundary and J08-Sep, Windsor and Maidenhead (Grid ref SU860764)
- M4 between J08-Sep and Windsor and Maidenhead boundary, Windsor and Maidenhead (Grid ref SU896786)
- M4 between Buckinghamshire boundary and J7, Buckinghamshire (Grid ref SU923799)
- M4 between J7 and Buckinghamshire boundary, Buckinghamshire (Grid ref SU934800)
- M4 between Slough boundary and A4, Slough (Grid ref SU934809)
- M4 between J7 and Buckinghamshire boundary, Buckinghamshire (Grid ref SU934805)
- M4 between Slough boundary and J6, Slough (Grid ref SU947796)
- M4 between J6 and Slough boundary, Slough (Grid ref SU970790)
- M4 between Windsor and Maidenhead boundary and Windsor and Maidenhead boundary, Windsor and Maidenhead (Grid ref SU985780)
- M4 between Slough boundary and J5, Slough (Grid ref TQ010779)
- M4 between J5 and J4B / M25, Slough (Grid ref TQ030781)
- M4 between J4B / M25 and Slough boundary, Slough (Grid ref TQ047783)
- M4 between Hillingdon boundary and J4, Hillingdon (Grid ref TQ060784)
- M4 between J4 and A4, Hillingdon (Grid ref TQ074778)
- M4 between J4 and A408, Hillingdon (Grid ref TQ074786)
- M4 between J4 and J3, Hillingdon (Grid ref TQ089784)
- M4 between Hounslow boundary and A312, Hounslow (Grid ref TQ104782)
- M4 between J3 and J2, Hounslow (Grid ref TQ147786)
- M4 between J2 and J1, Hounslow (Grid ref TQ186783)