What does a circular white sign with a red border containing '10 m' behind a truck silhouette indicate ('ograničenje dužine vozila')?

1. Prohibition of vehicles or combinations of vehicles whose overall length exceeds 10 metres (Zabrana saobraćaja za vozila čija dužina prelazi određenu dužinu)
2. Mandatory stopping distance of 10 metres
3. Road width restricted to 10 metres
4. Parking allowed only for vehicles exactly 10 metres long