Johnston Canyon Split Highway
Start
Exshaw
Canmore
Banff Gates
Since you are only going in and back out in a couple of hours, you don't need to stop and buy a park pass.
Johnston Canyon Turnoff
Wait at the start of the highway split for any cars ahead of...
Wait at the start of the highway split for any cars ahead of you to create a gap. Start your ride before the cars behind you catch up.
When the highway lanes join up again, turn around and do it ...
When the highway lanes join up again, turn around and do it again!