Which of the following actions is illegal when parking your vehicle?

Parking in front of a private driveway is illegal because it obstructs access for the property owner and can create an inconvenience for residents. Driveways provide necessary access to homes and businesses, and blocking them can prevent residents from entering or exiting their own property. Local laws often prohibit parking in front of driveways to ensure that property owners can use their driveways without obstruction.

The other options are generally permissible under normal circumstances: parking in a designated parking space is legal; parking on the street is allowed if there are no specific prohibitive signs; and parking next to another vehicle is typically acceptable as long as the overall parking rules and regulations are followed.