Originally Posted by geog_dash
Sounds like a pretty durable bike. What kind is it?
Maybe in addition to a banner on the door, you could put something on the dashboard - a note or a bike part - as a visual reminder that there is a bike up there.
It's a Trek X01 Cyclocross. Love all the suggestions, but when it burns down to it, I should have been bright enough to remember I had a bike on the roof!!!