That’s still the posted speed limit in most sections of the Trace. It drops to 40 MPH for a few miles just east of where it meets I-55. Think there’s another part near Tupelo with a lower speed limit, too. I drive the northern part of the Trace several times a year. Don’t think I’ve ever driven it for any significant distance without seeing somebody getting a ticket.
And it’s not just speeding tickets to worry about. Deer are plentiful, and they refuse to limit their crossing to where the signs are. Bicyclists use the road too, and there’s no bike path, so they’re in the traffic lanes. Most are smart enough to wear bright colors, but not all of them do.
That noted, it’s still a pleasant drive, if you like driving through national forests.