**High Occupancy Vehicle (HOV) lanes** are designed for vehicles carrying a specific number of people, as indicated by the lane signs. However, there are exceptions to this rule.

- **Vehicles for people with disabilities** can use the HOV lane even if only the driver is traveling. This is possible as long as the vehicle displays the **disabled badge**.
- Other vehicles that can use the HOV lane include motorcycles, passenger cars, and adaptable mixed vehicles that meet the HOV car requirements, buses weighing more than 3500 kilos, and emergency or road work service vehicles.

Therefore, a passenger car occupied only by its driver can travel in the HOV lane if it displays the disabled badge, thus complying with the permitted exceptions.