The Scottish Government is proposing trialling the speed restrictions in Oban, Biggar, Largs, Langholm and Maybole from next spring or summer with a view to improving safety for vulnerable road users such as cyclists, children, pedestrians, horse-riders and motorcyclists.
The locations were whittled down from a longlist of 14 towns and villages based on their accident rates, vehicle speeds and traffic data. The Scottish Government said it is not considering any additional trunk road sites for the 20mph limit.
Nairn, Keith, Inveraray, Golspie, Callander, Springholm, Crocketford, Aberlour, and Cromdale were also considered but ruled out because evidence suggested a 20mph limit would be "ineffective or impractical".
For a number of locations, including Inverary and Callander, there was either no record of traffic accidents involving vulnerable road users, or the rates were very low. Nairn and Keith - both located on the A96 - were eliminated because the width of the roads did "not support the use of a self-enforcing 20 mph limit".
However, the Scottish Government said traffic issues facing both communities would be considered as part of the route accident reduction plan (RARP) due to be carried out in 2014.
According to the Royal Society for the Prevention of Accidents (RoSPA), a pedestrian struck at 20mph has a 97% chance of survival; this falls to 80% at 30mph and 50% at 35mph.
Announcing the plans in Biggar, South Lanarkshire, Transport Minister Keith Brown said: "The five trials are being proposed that will seek to improve road safety generally, but we expect them to bring specific benefits for vulnerable road users, such as older people and cyclists.
"There have been a number of calls for lower speed limits and specifically 20mph limits and we have had to whittle these down to a number that will give us a meaningful overview of how this will work in a variety of locations.
"I know there will be some communities that are disappointed that they missed out but we will be looking at how their specific concerns can be addressed as part of our wider approach to speed management. The proposed pilot is an important step in our work to reduce accidents and casualties on the trunk network."
He said none of the pilot areas should require significant engineering or police enforcement to implement the reduced limit.
A consultation process will now begin with the local councils, community groups and other stakeholders to develop more specific proposals for each location.
Keith Irving, head of the campaign group Living Streets Scotland, said: "Many towns and villages are blighted by heavy, speeding traffic, damaging the local economy and environment while Scotland's pedestrian safety record has been poor for too long.
"This could be a first step toward tackling these deep-rooted challenges. It will be important to monitor the impact on both traffic speed and people's perceptions: our streets must be safe and feel safe for vulnerable road users."
Councillor Chris Thompson, chair of South Lanarkshire Council's Enterprise Services Committee, said: "We are firmly behind any proposals which make driving safer in our villages and towns.
"We have already introduced 20mph limits throughout the town to improve road safety and the plans now being brought forward for the A702 would complement those improvements."