Carrying the bike in the back of the car

[thekarens]

I have fork mounts attached to a piece of wood lying in the back of the Rav. Front wheel off, rear wheel rolls over wood and fork attaches to mount. Easy breezy, and takes less than a minute. http://www.performancebike.com/bikes...301730__400172

So, does this mean the bike is upright? If so, how do you keep it from falling over? I can see how the fork mount keeps the front of the bike from tipping, but what about the rear?