Rear Trailing Unit Distance : The maximum distance from the centre of the fifth wheel or tow coupling on the towing vehicle to the rear of the combination
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}