When did ABS become mandatory?

You would be amazed at how many violations I see on PSPs... Here's one (the only one) on our company's SMS results from 5/15/21 (about to fall off): "Cmv Other Than Truck-Tractor Manufactured On Or After March 1, 1998 Not Equipped With An Antilock Brake System." The "other than truck-tractor" refers to the violation occurring on a 2020 Great Dane trailer. I am assuming the light was inoperative.

EDIT: OOPS! I found a second one that I can only assume was related. It was written the same month on a different (2021) trailer as "Required Lamp Not Powered By Vehicle Electric" and the unit was placed OOS in MO. So yes, the different states will view it differently, and if the DOT has a hard-on for you that day, you're going to be sitting there a while. (it was the only violation found during a 35-minute inspection)

 

Anything march 98+ trailer pulled by a March 97 - non abs tractor can work the trailer off the brake lights and not a constant,

my truck was built in December 96, no abs

 

A 2000 Mack I used to work on had the ABS light in the speedometer. The speedometer failed and we could not get one with the ABS light in it so I drilled a hole in the dash and added one. Have a good look at your speedo with a bright light. It might be there.