Do you have any barriers to getting to work on time and meeting all scheduling expectations of the position?

The employer is asking these questions to look for any potential problems with scheduling. It is important that the employee and employer are clear up front whether or not overnight shifts will be required, and that if it snows you understand you must get to work, etc. Someone who lives 40 miles away from work may look like a risky hire. You want to assess your ability to fulfill your staffing requirements against their expectations. If you can work any shift, you want to reassure the interviewer that you understand the commitment and are ready for this type of scheduling.