Best friend busted

JunoBlack here, long time lurker, first time poster.
So my best friend was in a car with two people (read: two idiots) and they got pulled over for speeding.
In the end, the cops found less than two grams, a bowl, and a steamroller in the car all of which belonged to the driver. In addition, the driver and front passenger had a small amount on them.
My best friend, who was in the back seat, had nothing on him (he had left it at home because he NEVER goes out with stuff on his person). The driver didn't take responsibility for the two grams, the bowl, and the steamroller so everybody including my friend were charged with possession. Assuming the driver doesn't act like a man and own up to his stuff, is there any way my friend could get out of the charges?

Of course there are many things that can happen. A motion to suppress might get all the evidence tossed out, the prosecutor might see the true story and dismiss, or he might win at trial. All possible endings.