Yes, there is a secondary network which includes a lot of the minor roads to smaller communities. This secondary network is treated during extended periods of cold weather (defined as snow or ice most of the day). But not until the main route is clear.
The following criteria are used to determine which roads are salted as part of the secondary network:
Main access route to settlements with a population of 100 to 499.
Park and Ride sites
Car parking area.
Where problems have been identified on routes with a service interval of at least 30 minutes within any one hour of the day, in one direction of travel, or where a combination of multiple bus services meet this criteria.
Main highway access route to Devon County Council level 1 properties
Those council properties providing essential services which cannot be closed in severe weather – as defined during the swine flu pandemic emergency response.