A motorists' pressure group, angered by the new M4 speed cameras, is planning a slow-drive protest along the motorway.
Speed cameras are being used to enforce the speed limit on the M4
M4 Protest hopes the action will "show that safe driving is too complex to be measured in miles per hour".
Spokesman, Robin Summerhill said: "After £700m of fines, road deaths are going up, yet the greedy camera partnerships simply keep expanding."
The protest is due to take place along the Wiltshire stretch of the motorway on Saturday, 30 April.
Mr Summerhill, 52, added: "The motoring public is at breaking point and something has to give.
"I believe it is important that the entire ethos of speed cameras in the UK is re-examined from the very foundations.
"We've been running for less than 24 hours and already the response is amazing."
The Wiltshire Safety Camera Partnership recently introduced marked vans at fixed, permanent sites, along a 40-mile stretch between Bath and Hungerford.
It said it hoped they would reduce the high number of deaths on the route.