What does the painted red curb indicate?

• It marks a designated area where vehicles can park at any time.
• It designates a space where parking is allowed only for short durations.
• It indicates a reserved parking area for loading/unloading.
• It signals a fire lane where parking is strictly prohibited to ensure emergency vehicle access.
  Explanation:

  "Red zones are for emergency vehicles and fire hydrants. You can't stop, stand, or park there."