We just had a mechanic crushed by an industrial truck he was working on when the driver didn't realize he was not clear. One of the replies to the article in the newspaper was:
'Lockout-Tagout' safety ignored here, definitely.
The above policy is implemented by most all industrial / commercial concerns.
The policy means that the truck's keys are in the hands of the mechanic and the steering wheel or gear shift is immobilized with a tag explaining who has them and why. The policy works.
But it's too late for the mechanic here, RIP.
Those who have worked in industry may already know this policy. But it is a good idea for everyone to at least leave a note tied to something you're working on to avoid even the most minor of accidents (turning on a faucet while the air's being bled from the pipes for example).