Gantries erected along M4 and M5 as part of major upgrade
A total of 33 new gantries will be installed along the M4 and M5 around Bristol and north Somerset as part of a major upgrade to cut congestion.
The gantries will carry overhead signs to carry information on variable speed limits, traffic delays and junctions.
Highways Agency project manager, Paul Unwin, said: "They're ranging in size from about 22m to 50m and in weight from 26 tonnes to 35 tonnes."
Work will take place along motorway junctions 16 to 20 during most of July.
"Along the M6 in the West Midlands we have these gantries about every 800 metres or so to give information on speed limits and also junctions, so people can get in the right lane," Mr Unwin said.
"If you can get in the right lane early, that really helps improve the flow of traffic,"
A further seven existing gantries will also be upgraded so they can carry the new signage.
Diversion routes will be put in place and motorists have been warned to follow them rather than use satnav directions.