The reason they make the clain that the drivers were on pot is because when they test the victims they test for anything in the past few months, even years. Also, when they make their statistics they count everyine involved IN the accident, not just the people who CAUSED the accident. As for the pregnant girl, I've seen it and thought it was the dumbest thing ever.
NORML has released a document to the government, countering all their statements and begging them to at least stop lying to the American public. There's more info on their site:
www.norml.org
They also have a system which automatically tells you which legislators (in your area) to write to, writes the letter, and emails it for you. Political power in under two minutes!