A40 Denham roundabout Lane 1 closure

Planned

Start time: Fri, Mar 6, 2026 11:00 PM
Expected end: Sat, Mar 7, 2026 5:30 AM
Duration: 6 hours 30 minutes
Road: A40 – Roundabout At M40 J1/A40
Category: Road Maintenance
Direction: Clockwise
Carriageway: Singlecarriageway
Lanes affected: 1 of 1 lanes affected
Reason: Maintenance Work

Active

Planned

Cleared

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First published: Fri, Mar 6, 2026 5:02 AM
Last updated: Fri, Mar 6, 2026 6:29 PM
Cleared: Sat, Mar 7, 2026 5:30 AM

Latest update: A40 Denham roundabout Lane 1 closure

Coordinates: 51.560959, -0.493153
Latitude span: 51.560644 – 51.561276
Longitude span: -0.493225 – -0.493095
Bounding box centre: 51.560960, -0.493160
Location descriptions: roundabout at M40 J1/A40

Feed validity status: Planned
Overall feed start: Fri, Mar 6, 2026 11:00 PM
Overall feed end: Sat, Mar 7, 2026 5:30 AM
Feed window length: 6 hours 30 minutes
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

2 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Single Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 1 operational lane
Direction On Section: Clockwise
Direction Relative: Both
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {68F8FADF-37D0-4824-83FD-A65EAA260780}
Linear Element Type: Other
From Distance: 0 m
To Distance: 18 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.561114 -0.493182
51.560952 -0.493158

Segment 2

3 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Single Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 1 operational lane
Direction On Section: Clockwise
Direction Relative: Both
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {B8CD81A6-B542-4B36-85A8-3706D989AD6A}
Linear Element Type: Other
From Distance: 0 m
To Distance: 9 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.561196 -0.493208
51.561169 -0.493199
51.561114 -0.493182

Segment 3

2 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 0 operational lanes
Direction On Section: Clockwise
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {E7B1BF07-E6BF-43D9-BCC7-0EBCE7E842BF}
Linear Element Type: Other
From Distance: 32 m
To Distance: 41 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.561276 -0.493225
51.561196 -0.493208

Segment 4

4 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 0 operational lanes
Direction On Section: Clockwise
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {0ADD6897-E733-4876-B914-5C7C075721CB}
Linear Element Type: Other
From Distance: 0 m
To Distance: 19 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.560869 -0.493133
51.560824 -0.493095
51.560816 -0.493095
51.560699 -0.493095

Segment 5

2 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Single Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 1 operational lane
Direction On Section: Clockwise
Direction Relative: Both
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {2ECD94C7-03F6-4ADB-84CF-562BD531968C}
Linear Element Type: Other
From Distance: 0 m
To Distance: 9 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.560952 -0.493158
51.560869 -0.493133

Segment 6

2 coordinate pairs

Description: roundabout at M40 J1/A40
Carriageway: Dual Carriageway
Lanes Restricted: 1 lane restricted
Operational Lanes: 0 operational lanes
Direction On Section: South Bound
Direction Relative: Aligned
Height Grade: Start1 End1
Linear Element Road: A40
Linear Element Model: The Network Model
Linear Element Id: {1C6646EB-9EFE-43A3-A1D7-05AA5E400D7F}
Linear Element Type: Other
From Distance: 0 m
To Distance: 6 m
Gml Srs Name: EPSG::4326
Gml Srs Dimension: 2

Raw coordinate list

51.560699 -0.493095
51.560644 -0.493128

Geometry type: MultiLineString
Geometry points: 15
First coordinate pair: -0.493182, 51.561114
Road section segments: 1
Road section points: 15

View geometry JSON

{
    "type": "MultiLineString",
    "coordinates": [
        [
            [
                -0.493182,
                51.561114
            ],
            [
                -0.493158,
                51.560952
            ],
            [
                -0.493208,
                51.561196
            ],
            [
                -0.493199,
                51.561169
            ],
            [
                -0.493182,
                51.561114
            ],
            [
                -0.493225,
                51.561276
            ],
            [
                -0.493208,
                51.561196
            ],
            [
                -0.493133,
                51.560869
            ],
            [
                -0.493095,
                51.560824
            ],
            [
                -0.493095,
                51.560816
            ],
            [
                -0.493095,
                51.560699
            ],
            [
                -0.493158,
                51.560952
            ],
            [
                -0.493133,
                51.560869
            ],
            [
                -0.493095,
                51.560699
            ],
            [
                -0.493128,
                51.560644
            ]
        ]
    ]
}

View road section coordinates

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