Maverick drug question for non driver college student

I think i am on the right page. I am a student a local Tech college for Diesel mechanic. In our oral communications class (that i hate by the way) We have to right a report and present it to the class. Our tech school was one of the first if not the first to drug test us before we could be enrolled. As you can imagine companies poped up everywhere suing the school for different things (right to privacy, along with a few other things) after we all got tested, Only 5 kids out of over 1,000 failed the test which i was amazed at. But anyway i am doing my report on drugs in the work place more specifically in the trucking and heavy equipment industry. My question to you is if anyone can tell me what the company policy is on drugs. What kind of drug test do you take (Urine,mouth swab, blood, Hair follicle) how often and do they test you. And also whats you opinion on this subject as a driver do you think they should test more often? Do they test after every wreck or traffic incident? Before they hire you etc,etc. And last but not least does the company hire people with any kind of drug related back ground no matter if its been a year or 20? I'm asking this question to 3 different companies so i can pool the answers together to see what is most common. I found this site while surfing the net and seem to be a lot of people on here. Thanks in advance for your response. Any info will help

 

Of all the companies I asked you guys are the only one who responded thanks guys. Stay safe out there.