A sign shows a circle with a red X through it and a truck image inside. What does this sign mean?

PROHIBITION SIGNS use the same format as 'no parking' and other prohibition signs: white circle with a red slash or X through a symbol of the prohibited activity or vehicle. The truck prohibition sign means commercial trucks (over a specified weight or size) are not permitted on this road. This is a regulatory sign — driving past it with a prohibited vehicle is a traffic violation. Similar format: No left turn (circle with left-turn arrow and red slash); No U-turn (circle with U-turn arrow and red slash); No pedestrians (circle with walking person and red slash). The key: red circle + slash or X = PROHIBITION.