Which of the following statements about Class D vehicle inspections is true?

The statement that inspections must be conducted at designated inspection stations is correct. In Maine, Class D vehicle inspections are regulated to ensure that they are carried out in a consistent manner by facilities that meet specific standards. These designated inspection stations are authorized and licensed by the state, ensuring that all inspections conform to the required safety and emission standards.

This process helps to maintain a certain level of quality and reliability in vehicle inspections, ensuring that the inspection is done properly and thoroughly. By limiting inspections to officially designated stations, the state can oversee compliance and take corrective actions if standards are not met.

Other options mention scenarios that do not adhere to these regulations—for instance, suggesting that any licensed mechanic can perform inspections or that vehicle inspections can take place according to the vehicle owner's convenience undermines the structured approach that Maine employs to ensure vehicle safety and roadworthiness. Therefore, having a designated protocol enhances accountability and ensures all vehicles on the road are safe and compliant.