Edinburgh

The A8 begins at the West End of Edinburgh, in the New Town. The road originally also included Princes Street, but this stretch was declassified, as Princes Street is no longer open to all traffic.

The road continues westwards into the suburbs of the city passing Murrayfield and Corstorphine, often with an accompanying bus lane. Only once the road reaches the A720 City Bypass does it become a primary route, leading out past the Royal Highland Showground at Ingliston, and Edinburgh Airport.

At Newbridge, the A8 meets the start of the M8 and M9 motorways. From here the A8 is interrupted; it has been renumbered A89 until Bathgate, A7066 to Whitburn and then B7066 Harthill, until it resumes at Newhouse.

Glasgow

From Newhouse it runs parallel to the M8. Until recently there was no road of motorway standard between Newhouse and Baillieston in the eastern suburbs of Glasgow, and the A8 still carried all through traffic here, having been progressively upgraded to meet demand.^[1] However it was finally replaced in 2017 by the last section of the M8.^[2] It is now the principal non-motorway access between the Eurocentral business park and the settlements of Chapelhall and Calderbank, south of Airdrie.

Just prior to Junction 8 of the M8 it diverges from the motorway, and meets the A89 at Bargeddie while co-existing as the interchange for the M8 and M73. At a roundabout near Swinton it briefly merges with the A89 and heads towards central Glasgow. The A8 now passes through suburban Garrowhill, Barlanark, Wellhouse, Springboig, Cranhill and Carntyne as Edinburgh Road – much of which is a two/three-lane dual-carriageway, but an urban 30 mph (48 km/h) restriction is still applied – then past Haghill and Dennistoun as Alexandra Parade into the city centre at Glasgow Royal Infirmary and Glasgow Cathedral, where it follows the High Street and then the Saltmarket running north–south – meeting the A89 (Gallowgate) and the A749 (London Road) at Glasgow Cross. It splits for the complex one-way system, recombining prior to the junction at the start of the A814 that heads west along the Clyde, before crossing the river near The Gorbals, where it meets the end of the A74.

From there the A8 leads out of town through Tradeston, Kingston (passing under the M8's Kingston Bridge) Kinning Park, Cessnock and Ibrox as Paisley Road West, changing to Edmiston Drive past Ibrox Stadium, then through Drumoyne and Shieldhall as Shieldhall Road, Braehead as Renfrew Road and the town centre of Renfrew as Glasgow Road, Glebe Street and Inchinnan Road, passing to the rear of Glasgow Airport at Inchinnan, crossing over the M8 east of Bishopton and meeting it again at the motorway's western end, Junction 31 between Bishopton and Langbank.

The A8 becomes the primary route again and takes traffic through Port Glasgow. Its terminus is in Greenock at a large roundabout with the A78 road and the A770 to Gourock, which was the former terminus of the A8.