In the short term, letters.
You must argue a legitimate reason why this route must not go ahead.
Possible stages in a protest letter:
1. State how you are immediately affected. It is important to emphasize
how it will alter your life. Complaints can be made by anyone, but
those immediately affected must be considered.
2. State how the community is feeling on a whole. This will indicate
that others may add to the numbers and there may be popular support
against the route and therefore delays due to protests etc.