Section 13 of chapter 6C of the General Laws, as appearing in the 2016 Official Edition, is hereby amended by adding the following subsection:-

(d) The department shall design and implement a state wide program for charging toll rates that are different depending on time of day, with the goal of relieving congestion for motorists. The program shall be based on variable pricing, including a discount structure including off-peak discounts of at least 25 per cent and peak premiums of at most 25 per cent. Only vehicles with transponders issued by the commonwealth shall be eligible for discounts.  Provided further that the program shall commence no later than December 31, 2022. The department shall transmit an annual report to the clerks of the house and senate detailing the scope of the program, implementation challenges, lessons learned, and proposed next steps to use tolling policies as a means to alleviate congestion on roadways.