The Portway is a major road in the City of Bristol. It is part of the A4 and connects Bristol City Centre to the Avonmouth Docks and the M5 motorway via the Avon Gorge. The road was constructed following World War I in order to provide improved access to the ports at Avonmouth Docks, which had replaced Bristol Harbour as the major local centre for commercial shipping. Upon opening on 2 July 1926, it was the single most expensive road project in Britain, costing £800,000 (now about £49 million). The construction posed a number of significant engineering challenges, including long and deep rock cuttings, a viaduct over the River Trym, and retaining walls against the gorge adjacent to the River Avon. Falling rocks have since been a problem along the Portway, particularly at the southern end c