It shall be unlawful for any person to drive or move or for the owner to cause or knowingly permit to be driven or moved on any highway any vehicle or combination of vehicles in such unsafe condition as to endanger any person or which does not contain those parts or is not at all times equipped with such lamps and other equipment in proper condition and adjustment as required in the code of Iowa, as amended, or equipped with one or more unsafe tires. (1978 Code §23-107)