drug/alcohol testing policy: effective?

gatt wrote:

They might as well administer a sleep test.

That would certainly be a great idea, if they could do it. Several of the
existing regulations on airline pilots, truck drivers, and railroad engineers
have no other purpose than to ensure that these people have at least the
opportunity to get enough sleep.

Drugs and alcohol just don't seem to be a significant source of
aviation accidents.

And there's no way to tell to what extent that's due to the fact that random
testing is required in some fields of employment.

George Patterson
The desire for safety stands against every great and noble enterprise.