M4 eastbound Jct 21 to 20 - lane closures

Planned

Start time: Mon, Aug 17, 2026 8:00 PM
Expected end: Tue, Aug 18, 2026 5:00 AM
Duration: 9 hours
Road: M4 – M4 Eastbound Between J21 And J20
Category: Road Maintenance
Direction: Eastbound
Carriageway: Dual Carriageway
Lanes affected: 1 of 3 lanes affected, 1 of 2 lanes affected
Reason: Maintenance Work

Live incident

Active roadworks

Planned

Cleared

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First published: Wed, Jul 29, 2026 3:34 PM
Last updated: Mon, Aug 17, 2026 8:54 AM
Cleared: Tue, Aug 18, 2026 5:00 AM

Latest update: M4 eastbound Jct 21 to 20 - lane closures

Coordinates: 51.558018, -2.558016
Latitude span: 51.553548 – 51.563152
Longitude span: -2.564788 – -2.553043
Bounding box centre: 51.558350, -2.558916
Location descriptions: M4 eastbound between J21 and J20

link road from M4 J20 eastbound to M5 J15 northbound

link road from M5 J15 to M5 J20 westbound

M4 eastbound within J20

Feed validity status: Planned
Overall feed start: Mon, Aug 17, 2026 8:00 PM
Overall feed end: Tue, Aug 18, 2026 5:00 AM
Feed window length: 9 hours
Probability code (raw): probable
Compliance option (raw): mandatory
Source identification (raw): roadworks

Management type value: other
Contra-flow flag (raw): false
Width restriction flag (raw): false
Height restriction flag (raw): false
Weight restriction flag (raw): false

Segment 1

12 coordinate pairs

Description: M4 eastbound between J21 and J20
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 3 operational lanes
Direction On Section: East Bound
Direction Relative: Aligned
Height Grade: Start2 End1
Linear Element Road: M4
Linear Element Model: The Network Model
Linear Element Id: {851BB8E6-6940-4369-BCF5-A96FE8932F11}
Linear Element Type: B Carriageway
From Distance: 584 m
To Distance: 1,098 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.563152 -2.564788
51.563039 -2.564578
51.562736 -2.564011
51.562645 -2.56385
51.562522 -2.563576
51.561416 -2.561701
51.561086 -2.561178
51.560881 -2.560872
51.560732 -2.560668
51.56038 -2.560188
51.560139 -2.559868
51.559898 -2.559545

Segment 2

2 coordinate pairs

Description: link road from M4 J20 eastbound to M5 J15 northbound
Lanes Restricted: 1 lane restricted
Operational Lanes: 2 operational lanes
Direction On Section: North Bound
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: M5
Linear Element Model: The Network Model
Linear Element Id: {0B7B371B-00B1-4C02-ACC7-CE21C8F7A7C6}
Linear Element Type: B Carriageway Entry Slip
From Distance: 0 m
To Distance: 54 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.553882 -2.553621
51.553548 -2.553043

Segment 3

12 coordinate pairs

Description: link road from M5 J15 to M5 J20 westbound
Lanes Restricted: 1 lane restricted
Operational Lanes: 2 operational lanes
Direction On Section: East Bound
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: M4
Linear Element Model: The Network Model
Linear Element Id: {ABB6A540-40C4-4072-BF82-7D58F2B5555B}
Linear Element Type: B Carriageway Exit Slip
From Distance: 98 m
To Distance: 462 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.556672 -2.556297
51.556668 -2.556294
51.556579 -2.556214
51.555494 -2.555356
51.554866 -2.554858
51.554539 -2.554532
51.554531 -2.554524
51.554464 -2.55444
51.554205 -2.554112
51.554116 -2.553995
51.554071 -2.553923
51.553882 -2.553621

Segment 4

2 coordinate pairs

Description: M4 eastbound within J20
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 2 operational lanes
Direction On Section: East Bound
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: M4
Linear Element Model: The Network Model
Linear Element Id: {28ED533E-2B58-4717-A7A3-2B792A8EAEAA}
Linear Element Type: B Carriageway
From Distance: 0 m
To Distance: 98 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.557446 -2.556984
51.556648 -2.556376

Segment 5

6 coordinate pairs

Description: M4 eastbound between J21 and J20
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 3 operational lanes
Direction On Section: East Bound
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: M4
Linear Element Model: The Network Model
Linear Element Id: {BBCF13CD-84AD-4542-B91E-D5E3F80455EE}
Linear Element Type: B Carriageway
From Distance: 0 m
To Distance: 325 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.559898 -2.559545
51.559388 -2.55895
51.558879 -2.558366
51.558404 -2.55787
51.558351 -2.557826
51.557446 -2.556984

Geometry type: MultiLineString
Geometry points: 34
First coordinate pair: -2.564788, 51.563152
Road section segments: 1
Road section points: 34

View geometry JSON

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            [
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            [
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}

View road section coordinates

Cause type: Road Maintenance
Detailed cause: Maintenance Work
Compliance: Mandatory
Probability: Probable
Validity status: Planned
Road management: Other