Protesters will find it harder to climb motorway gantries built using a new design, National Highways said.
The roadside structures will be “more resilient to trespassers” as steps for maintenance crews will be inside pillars rather than outside, according to the government-owned company.
Gantries above the M25 were repeatedly scaled by Just Stop Oil activists in November last year, bringing traffic on the UK’s busiest motorway to a halt.
National Highways, which is responsible for England’s motorways and major A roads, held a competition to replace existing designs.
It said: “Although security issues did not form part of the original specification, the new design will be more resilient to trespassers due to entry being concealed within the pillars, making it more difficult to access without authorisation.”
The winning entry was produced by London-based architecture company Useful Studio.
It was selected for its “simplicity and elegance”.
National Highways executive director for operations, Duncan Smith said: “Existing designs tend to emphasise function over form.
“Our challenge is to create innovative structures that can accommodate the required signage and equipment that are more sympathetic to the environment.
“In selecting Useful Studio as the winner, the judging panel admired the simplicity and elegance of the pared-back design approach.”
Roads minister Richard Holden said: “Congratulations to Useful Studio and National Highways for their success in creating a modern, secure design that is set to redefine the look and feel of our motorways and roads.
“Their innovative approach is bound to improve the daily journeys of countless motorists while also contributing to a more sustainable future.”
Useful Studio will work with National Highways to develop its design concept.
It is expected to become the standard design for new gantries in around two years.
The competition was part of a wider push to beautify motorways and major A-roads.
Design guidance published by National Highways in July last year included recommendations such as “minimising clutter” and providing “clues” about how to drive.