What is a collective noun for motorway that starts with s?

There isn't a common collective noun for a motorway that starts with "s." Collective nouns for roads typically describe a network or system, such as:

* Network of motorways

* System of motorways

* Grid of motorways

You could also use a more descriptive phrase, like:

* The stretch of motorways

* The series of motorways

* The route of motorways

If you are looking for a more specific and creative term, you could invent your own!