Section 19I. Notwithstanding any provisions of this chapter or any other law to the contrary, the maximum vehicle width as provided in section nineteen, maximum vehicle weight as provided in section nineteen A and any minimum speed limit on any way shall not apply to any vehicle being operated on a public way within two hundred yards of the work site of said vehicle, if said vehicle is being used in the performance of duties pursuant to a contract with the commonwealth, any political subdivision thereof or any state authority regarding construction on a public way.