Complex sentence: Other radial roads, such as the M3 or M23, were truncated in outer London far from their intended terminal junctions on Ringway 1 or simply not built at all in a form recognisable from the Ringway proposal.
Split into simpler sentences: Other radial roads, such as the M3 or M23, were truncated in outer London far from their intended terminal junctions on Ringway 1. Others were simply not built at all in a form recognisable from the Ringway proposal.