N.H. Rev. Stat. Ann. § 265:159

Transporters of manufactured or modular housing shall be responsible for causing the least possible inconvenience to other traffic by using every opportunity to allow following traffic to pass. If traffic buildup behind the transporting unit becomes 6 or more vehicles, the entire transporting unit shall pull off of the traveled way to allow traffic to pass. The transporter shall locate a safe place, which allows the towing load to clear from the roadway, so that traffic following the load can safely pass.