The M898 is one of the shortest motorways in the UK, it is also the highest numbered. It opened in advance of the Erskine Bridge as part of Bishopton Bypass Stage 1 and Bridge South Approach Roads in December 1970. It begins at Junction 30 of the M8 and ends only one mile later at an interchange with the A726. It continues as the A898 via the Erskine Bridge before joining the A82.
Being the westernmost road crossing of the River Clyde it is also well used by long distance and tourist traffic travelling to and from Glasgow Airport, the Loch Lomond and Trossachs National Park and the Scottish Highlands.
LOCATION: M898, Renfrewshire
OPENING DATE: December 27th 1970
DESIGNER: Freeman Fox & Partners
CONTRACTOR: Whatlings (Civil Engineering) Ltd
TOTAL SCHEME COST: £2.1million (£29.8 million at 2017 prices)
The M898 has no hard shoulders along its length and has one emergency layby on the southbound carriageway. The route is constructed to rural motorway standards and has a speed limit of 70mph on both carriageways. It is generally considered to be the shortest signposted mainline motorway in the UK.
Until the early 2000s each of the slip roads connecting to the motorway from the M8 were two lanes wide. This was reduced to one lane for safety reasons following a number of accidents.
For details on the A898 and Erskine Bridge see the appropriate page in the Other Routes Index.
The M898 connects to the M8 J30 Craigton Interchange via a large "Semi-directional T", free flowing three-level interchange. This allows for movements between the two motorways in all directions. The M898 has one junction which is named “Spectacles Interchange”. The junction layout is that of a "Folded Dumbbell" type junction. Immediately after this junction the motorway loses its motorway classification and becomes the A898. Until March 2006 the toll booths of the Erskine Bridge were a major feature.
The need for an upstream crossing of the River Clyde was first considered by the Abercrombie Report which suggested a route in almost the same location as that built. It was always intended that the bridge would connect with the upgraded A8 route between Greenock and Glasgow however motorway classification only came in the late 1960s when it was decided that schemes connecting with the Renfrew Bypass would also be to motorway standard. The road and it’s associated works were designed by Freeman Fox and the main contractor was Glasgow based Whatlings Construction. Their total cost was £2.1 Million.
Spectacles Interchange (or J1) was used as a temporary terminus of the M898 before the bridge opened on the 2nd July 1971. Today this junction connects with the A726 and B815 via a pair of large roundabouts. This junction has long slip roads that peel back facing south away from the bridge. Although the junction is “folded” it still has full access to and from the motorway and the winding slip roads have a 70mph limit. This layout was deliberately chosen to suit the toll plaza for the Erskine Bridge. The slip roads were once two lanes wide, but in recent years have been narrowed to single width due to safety reasons.
The dual carriageway A726 from Erskine passes through Spectacles Interchange. This junction was originally envisioned to connect with the proposed Erskine Expressway that was detailed in the Greater Glasgow Transportation study. The route was to have followed the route of the B815 towards Bishopton before joining the M8 via a limited access junction.