SECTION 1.  Section 19A of Chapter 90 of the General Laws, as appearing in the 2006 Official Edition, is amended by inserting, in line 40, the following new paragraph:-

“Notwithstanding a provision of this section or any other section to the contrary, the maximum gross vehicle weight limit, bridge formula limit and axle weight limit for any vehicle or combination of vehicles equipped with an idle reduction system may be increased by a quantity necessary to compensate for the additional weight of the idle reduction system as provided for in 23 U.S.C. Section 127, as amended. In no case shall the additional weight increase allowed by this subsection be greater than four hundred pounds. Upon request by an appropriate law enforcement officer, the vehicle operator shall provide proof that the idle reduction technology is fully functional at all times and that the gross weight increase is not used for any purpose other than for the use of an idle reduction system.  For purposes of this section, an idle reduction system is any system that provides heating, cooling or electrical service to a commercial vehicle cab for the purpose of reducing vehicle idling.”