http://www.bbc.co.uk/news/uk-scotland-25407233
"The five trials are being proposed 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."
"The proposal does not include traffic calming measures. The limits are to be "largely self-enforcing""
So if these are going to provide such benefit, and will require only limited infrastructure changes, perhaps simply a new sign, why have so many towns been ruled out ?
"Pilot schemes in a number of other locations were considered, but rejected as being "ineffective or impractical".Those not going forward to consultation are: Keith, Nairn, Inveraray, Golspie, Callander, Springholm, Crocketford, Aberlour and Cromdale."