What should be the first action if an ambulance encounters an unexpected roadblock during a response?

The correct course of action when an ambulance encounters an unexpected roadblock is to contact dispatch for alternative routes. This step is crucial because dispatch maintains comprehensive knowledge of the area and can provide updated information on road conditions, alternative routes, and potential delays. They are specifically equipped to guide emergency responders safely and efficiently, ensuring that patient care remains the priority and that response times are minimized.

Turning back to the station is not advisable, as it could significantly delay the response to the emergency. Driving around the roadblock without authorization could also lead to legal issues, safety hazards, and potential accidents. Finally, simply stopping and waiting for further instructions does not address the need for timely action and could result in unnecessary delays in delivering care to a patient in need. Thus, contacting dispatch is the most effective and responsible action in this scenario.