Motorway Database
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Factfile - Images - Timeline - Exit List
This one is 'the other' motorway spur from the confusing junction 8/9 of the M4. Chris Bertram points out that since its sibling the A404(M) has junctions numbered 9A and 9B to fit in better, this should end at 8A.
The reason this exists is that the A404(M) was originally the western end of the M4. When the westward extension came, it left the A404(M) as a spur, and a new junction here. This was too close to the original junction 8, which had served the A308, and so a connection was built to link the new junction with the A308. The new road was called A308(M).
This might be the UK's shortest motorway - but it depends which way you interpret "shortest". Take a look at the page of this road's rival in shortness, the A64(M), for the full story.
Factfile
| Start | Stud Green (M4) |
| Finish | Maidenhead (A308) |
| Passes | None |
| Length | 0.5 miles |
| Terminates | None |
| Spurs | None |
| Meets | None |
Images
Views of the A308(M) from on and off the road. If you have a photo to contribute, contact me.
Looking west from the A308 end, and you can see pretty much the entire motorway. The A308(M) is fully featured in terms of alignment: as you can see here, it has a straight bit and a bend.
Photo by Dave Ryan
Approaching the A308 from the M4, the direction sign looks poor for a motorway terminus - not even a primary route to continue along! The surface here isn't looking too healthy either.
Photo by Dave Ryan
Getting nearer the end - where do we go?! The carriageway seems to come to an abrupt halt in front of a large bush ahead, but in reality it's a roundabout. Thank heavens for that.
Photo by Dave Ryan
Construction Timeline
When the various parts of the A308(M) were built, listed in chronological order.
| Open | Section |
|---|---|
| 1971 | Entire motorway |
Exit List
All the junctions and destinations along the route.
| Junction | Westbound | Eastbound | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| (M4 J8/9) | London Slough Heathrow  M4  (M25 ) |
M4 (M25) |
WEST |
M4 A404(M) |
N/A   |
|||||
| The WEST Reading M4 |
||||||||||
| Maidenhead High Wycombe A404(M)   |
||||||||||
0.6 miles,
2 lanes  |
 0.6 miles, 2 lanes |
|||||||||
N/A  |
A330 A308 |
 EAST |
A308 |
Maidenhead A308 |
||||||
| Windsor A308 |
||||||||||
| Bracknell A330    |
