No more smart motorways will open without additional safety measures in place, the government has said.
Transport Secretary Grant Shapps said any new road without a hard shoulder would need radar technology installed to detect stopped cars first.
Smart roads use measures to cut traffic such as opening the hard shoulder, but MPs have questioned their safety.
The plan comes after several fatal accidents and concerns about the safety of smart motorways.
In a written statement to Parliament Mr Shapps that per hundred million miles driven there were fewer deaths on smart motorways than conventional ones.
Despite this, he said, "we are determined to do all we can to help drivers feel safer and be safer on our roads - all our roads".