The driver was on a parkway with an illegal speed limit. But I repeat myself. All the parkways around Boston have illegal speed limits.
The agency in charge has no record of approving any speed limits ever, as far as I can tell. (Same for stop signs.) They have an inventory of speed signs they discovered on their roads in the 1970s. Nobody knows where they came from or why. Good enough? Not in my book.
The law says first an engineering study, then official approval, then posting.
In this area I have specific reason to disbelieve the signs. I did a speed study north of the crash site and found the limit should have been 40. To the south, 45. A divided highway without a legal speed limit posting is a 50 mph zone.
In Massachusetts you can’t be convicted of disobeying an illegal sign. But it’s not over for this driver.
The prosecutor is allowed to argue that disobeying an illegal sign is reckless driving. The driver could prove the signs are illegal and still go to jail, just not for speeding. And that’s part of the reason the signs are present.
So the agency can say “it’s not our fault.”