When is it illegal to use parking lights only?

Using parking lights only while parked on a street or roadway where other vehicles can approach is against traffic regulations because it can create confusion and pose safety risks. Parking lights are intended to enhance visibility for parked vehicles, but they are not sufficient to signal the presence of a vehicle in an active roadway. Proper use of headlights is crucial in these situations, as they provide clearer visibility to other drivers and reduce the likelihood of accidents.

In contrast, in a private driveway, during nighttime hours, or in designated parking lots, using parking lights can be more permissible under specific conditions, as these scenarios often involve less traffic and diminished risk of collisions. Therefore, the prohibition of using parking lights only in scenarios where vehicles might approach ensures that drivers maintain a high standard of safety on public roadways.