Traffic cameras show the tailback between junctions 28 and 29.

BBC: Queuing traffic on the M4 between J28-29 on Friday morning

The M4, where traffic travelling into London is moving slowly between junctions 2 and 3.

BBC: M11 northbound on Friday

He said part of the problem with the road between Huntingdon and Cambridge was the number of junctions which mixed local traffic with heavy goods vehicles.

BBC: A14 at rush-hour