Chiswick flyover

The Chiswick flyover is a short elevated section of the M4 motorway in the western approaches to London, United Kingdom. The flyover in the west London suburb of Chiswick, was opened in 1959 with the intention of reducing congestion and the impact on local traffic of vehicles travelling around London on the North and South Circular Roads and between London and the west on the Great West Road. Although it was not originally built as a motorway, it was later incorporated into the M4 motorway.
The original Chiswick flyover carries the first half a mile of the M4 from its start at junction number 1. The flyover was extended to be over two miles long in the early 1960s, forming part of the M4 junction 1 to junction 5 section that was opened in 1965. The first one-and-a-half miles of the flyover tracks the course of the A4 which is directly beneath it, effectively forming a two-tier road system. It then turns approximately west north-west across Boston Manor Park before the M4 returns to ground level, and widens from two to three lanes in each direction as it heads west through the grounds of Osterley Park.

Wikipedia