The speed limit in 80 towns and villages in the Scottish Borders will be cut to 20mph.
The pilot project is expected to be rolled out from early October to December in settlements where the existing limit is 30mph. It will run for up to 18 months.
Councillors approved the move on Thursday, which aims to encourage safer active travel in the local authority.
It will be subsidised by £1.2m from the Spaces for People programme, funding which will also support a number of trial 40mph areas.
A report is due to be brought back to the council in 12 months, recommending which schemes to retain or remove.
The remaining six months of the trial will then be used to implement permanent changes.
The 20mph trial does not include sections of trunk roads, which run through towns and villages including the A68, A7 south of Galashiels, A6091 Melrose Bypass, A702 and A1.
However, discussions are ongoing with Transport Scotland on the prospect of these roads being included in the scheme.
Councillor Gordon Edgar, executive member for roads and infrastructure at the council, said: “Since we announced the Spaces for People programme in the Scottish Borders, there has been considerable discussion about the various projects in particular the 20mph pilot in our towns and villages.
“It’s worth reiterating that this is a trial but has the potential to help our communities’ lead healthier lifestyles which is why we want to work with Sustrans Scotland to try out these new measures.
“Advanced notification will be provided to the public ahead of the new 20mph limit being introduced in their communities.”
The full list of towns and villages which are part of the 20mph trial is available here.