A friend asked me if I could translate this to Thai but it's a bit beyond my current level:

STRICTLY NO UNATTENDED PARKING IN THIS AREA

Please do not park in this area with your car unattended This area is for pick up & drop off as well as emergency services. Thank you for your future co-operation.

Thanks for any help.

I will start off,

ห้ามจอดรถที่บริเวณนี่

รถยนต์ฉุกเฉินเข้าออก

ขอบคุณ

this needs tidying up, words like, กรุณา and other polite particles are missing, depends on whether you are making a request or issuing an order.

I see so many of these type of signs outside peoples houses and shops, they never read the same.

Lets see what the experts have to say.

ห้ามจอดรถบริเวณนี้เด็ดขาด ยกเว้นรถรับส่งของ

Give an inch and they'll take a mile. I'd just leave it as straight to the point as possible. Emergency vehicles are a given ... and the sympathy vote / respect for the fact it could be for emergency vehicles probably wouldn't fly in the same way as it might in the west.

Thank you both for the help.