With alcohol refusing a breathalizer is considered an admission of guilt.It would not be the same with a drug test as the drug can stay in your system for a period of time, while not affecting your ability to drive, and submitting to a drug test that would show you have consumed drugs at some point could have an impact on your job or your reputation.Browsing through ads on Craigslist (yeah, bad idea I know) it seemed like every 13th girl or so said this. 420 was the California police radio code for a marijuana arrest in progress.
And as stated above, it can cause impairment, just as alcohol can. Similar to opium, consumed mainly by Asians, the criminalization of marijuana was used to repress the ethnic traditions of an ethnic minority.
Additionally, Mexicans were often interacting with black people in the south and giving them pot, which caused a great deal of paranoia as well.
Obviously the more you smoke something the more likely it is that you will have cancer.
Pot can result in brain damage, especially in young people. 'White men' invented alcohol, but pot was mainly consumed by ethnic minorities (mainly Mexicans in the US).
And let's not get started on what could happen if the drug is laced with something, which can be quite common.
This comes from my own personal experience with the drug (mainly how I've seen other people react when high, but also from the few times I smoked pot when I was younger... I personally think that it should be illegal to drive while heavily influences by any substance, which includes alcohol, marijuana, cocaine, hash, heroin, whatever.
I wasn't going to be the one to bring it up, but...
some of the rumors about the number claim it was started by Neo-Nazis to commemorate the "holiday".
It would be very easy for a person to refuse a blood test, and hard to get a conviction for impared driving when a person refuses to take the test.