Animal/vehicle collisions: Lobby your municipality to install focused road lighting. (IE: Light the road, not the sky.)
Antifreeze/Engine Coolant ingestion deaths: Use Sierra non-toxic antifreeze.
Arthritis: Sea Jerky Treats (This stuff has been a miracle for dogs I know.)
(DIY Fleabusters: Remove your pets from carpeted areas, sprinkle Borax & work it into the carpet with a broom. Let it sit for several hours. Vacuum. This stops fleas for a year or more!)
Reduce stray cat populations: Lobby for a Trap/Neuter/Return program.