An important issue to be addressed in transit security, in particular for driverless metro, is the assurance that a vehicle is empty before it returns to the depot. Customer specifications in recent tenders require that an automatic empty vehicle detector is provided. That improves system security since it prevents voluntary (e.g. in case of thieves or graffiti makers) or involuntary (e.g. in case of drunk or unconscious people) access of unauthorized people to the depot and possibly to other restricted areas. Without automatic systems, a manual inspection of the vehicle should be performed, requiring considerable personnel effort and being prone to failure. To address the issue, we have developed a reliable empty vehicle detection system using video content analytics techniques and standard on-board cameras. The system can automatically check whether the vehicles have been cleared from passengers, thus supporting the security staff and central control operators in providing a higher level of security. © 2013 Springer-Verlag.