Dial cash into the exercise. If you can their cash. For example, if a transport company, how much do they spends in brakes, fuel etc.? If a manufacturing company, how much do their rejects and re-workings cost? Then the question is: How much would they have saved if their employees had stuck to the company's procedures? These minor deviations from procedures have a cost. They may also compromise safety. The next logical step to to monitor larger deviations from policy which will be by definition, less safe. The next step is to look at serious incidents. I hope you see where I'm going here.
By paying attention to the minor deviations from policy you'll be chipping away at the bottom of the "risk iceberg", thus making the operation both more profitable and at the same time, safer.
PM