Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

Dan Kieffer of PACCAR Inc., speaking for a group of heavy-duty North American truck manufacturers including Volvo and Daimler, said, “Unnecessarily stringent engine standards will only exacerbate today’s trend of delaying new truck purchases,” and consequently keep older, not-as-clean trucks on the road.

Answer: product_or_material_produced: Volvo, truck; product_or_material_produced: PACCAR, truck