听力原文：Hello! We will shortly be arriving in Southampton. For safety, may I advise passengers when returning to the car deck, to hold the hand rails and take extreme care at all times. I'd like to remind passengers that smoking is strictly forbidden and drivers are requested not to start their engines until instructed. Please ensure that car doors are closed and refrain from using mobile phones before the deck is lowered. Foot passengers are requested to remain seated until the ship is alongside. Thank you for traveling with Red Funnel and wish you all a safe onward journey. What is the main purpose of this announcement?