Federal and state regulators in Alaska say they’re working to stem what has been a growing number of tanker-truck accidents in recent years -- including three big rollovers since September that dumped thousands of gallons of diesel fuel into woods and wetlands. Residents in towns along the Richardson Highway where those and many other spills have occurred say they worry an out-of-control fuel tank will slam into traffic or damage fish habitat with a spill, including the salmon-rich Copper River with its prized fisheries.