i am not sure of putting piss on the tires, it might lead to the dog making a false hit. which then inturn leads to the cop finding your stash.
The easiest way to stay out of jail, is to know your state laws on marijuana.
Do some research on your states search and seizure laws as well. ( these can be found on the internet fairly easy ) If you do get caught USE YOUR RIGHT TO REMAIN SILENT the only words out your mouth should be I WANT A LAWYER.
When transporting marijuana make sure car is in proper running order ( dont want to break down with a shit load of weed in your trunk. ) Make sure all lights work properly, blinkers, head lamps brights too. License plate light. etc.... Make sure no cracked windshields or to dark tint. Good tires, wear seatbelt and obey all traffic laws. Make sure your drivers liscense is valid and you have no outstanding warrants. Do not smoke prior, or during transport but definately smoke after transport it really helps to relax you after such an stressful drive. Go alone!!!