From Community Notes in the January 26, 2007 issue of the Watertown Tab:

Disabled vets gain easier access to parking plates The commonwealth of Massachusetts has opened wider access to special license plates for veterans. The legislature strongly advocated for the passage of a law that will now permit veterans whose physical impairments already qualify them for special parking accommodations and who have a service-connected disability rating of 60 percent or higher to obtain a disabled veteran license plate, free of charge.

The new law is Chapter 419 of the Acts of 2006.