Usually have mine on scan most of the time. There are a few narrow bridges in my area & truckies call when they are approaching them on channel 40 & I have that set as the priority channel.
Some of the State Forests that are regularly logged will have a designated channel to monitor for logging trucks & some roads have signs every 5 kms along them. Good practice on these roads to send a call on the designated channel - "South on Bobs Rd at the 24 km marker" for example to give other drivers a bit of warning.
List of Channel Allocations - http://www.uhfcb.com.au/80-Channel-UHF-Information.php