Dumfries and Galloway Council and Sustrans will trial the speed reduction measures for 18 months.
South Scotland MSP Colin Smyth has welcomed the initiative and called for a wider rollout of the lesser speed limit in town centres across the region.
He said: “I have been a long-standing supporter of the ‘20’s plenty’ campaign so I welcome this move by Dumfries and Galloway Council to expand 20 mph zones.
“However, I would like them to go even further than just Dumfries town centre. Many of our schools have 20 mph zones, but this should be expanded to cover the whole neighbourhood near the school. Why have 20 mph next to a school but not next to the play park around the corner?
“There would still be exemptions, such as the key main arterial routes heading into a town remaining at 30 mph, but all those streets off the arterial routes, such as next to housing, would be reduced to 20 mph making them safer and improving our environment.
“There are a whole host of benefits of 20 mph zones. Ultimately, they save lives. If a pedestrian is struck by a vehicle at 20mph they have a 97 per cent chance of survival, but just 10mph faster means the survival chance drops to 92 per cent, all for the sake of someone arriving somewhere slightly earlier.”
Sustrans is welcoming feedback on the scheme throughout the trial period at www.sustrans.org.uk/space-to-move.
