[5][7] An elevated road employing reinforced concrete balanced cantilever beam supports with a single central column.

The deck spine and wings are of hollow prestressed concrete design, with each span being tensioned by longitudinal tendons (four clusters, each of sixteen 29 mm (1.1 in) steel cables).

[8] The flyover was designed by G. Maunsell & Partners, Consulting Engineers, led by Peter Wroth[9] and is 622 metres (2,041 ft) long.

[10] The system was initially successful,[11] though a £4800 bill for the 1962–63 winter (equivalent to £100,000 in 2023) "so shocked Hammersmith Borough Council that, as a protest, it cut off the electricity".

To avoid a conflict of interest Marples undertook to sell his controlling shareholder interest in the company as soon as he became Minister of Transport in October 1959, although there was a purchaser's requirement that he buy back the shares after he ceased to hold office, at the price paid, should the purchaser so require.

[16][17] The Fulham & Hammersmith Chronicle claim that they were contacted on 14 December 2011 by a whistleblower who revealed that problems with the structure were far more severe than was being made public.

[25] In February 2015 Johnson suggested a toll charge might be needed to cover the estimated £1.5 billion cost of building the tunnel.