The B800 is a short road in eastern Scotland, connecting the Forth Road Bridge to Kirkliston. It is a two-way single carriageway road.
It was formerly known as the A8000, when it was the main road from the bridge to the M9 motorway and the M8 motorway. The A8000 was under the control of the City of Edinburgh Council, not a Trunk Road under the control of the Scottish Executive. Despite this, it was one of the most important strategic routes in the east of Scotland, carrying traffic from Fife, and further north, to the central Scotland motorway network, and the City of Edinburgh Bypass. During the morning and evening rush hours it was often jammed nose-to-tail for its entire length.
It was replaced in this function in September 2007, when a new section of the M9 which bypasses the B800 was completed. During September 2009 signs amending the numbering of the A8000 to the B800 appeared at the start of the former A8000 and on the northbound slip road of the A90 at the Echline junction.