just checked wikipediaa---- team members can do up to 7 roadblocks each!
sorry, but wiki can be edited by anyone...so we do not trust it for that kind of info.
In season 10, Karlyn did 7 roadblocks while Lyn only did 5 of them. Same thing in season 16 where Brent did 7 and Caite did 5.
Season 10 had 13 Roadblocks (Leg 7 had an unaired one, but there was spoiler video to show it was there), so clearly someone needed to do more than 6 Roadblocks. Season 16 had the double Roadblock leg, so it seems the limit was increased to 7 per person. In episode 10 of this season, before opening the roadblock clue, Vicki stated "Who's feeling peckish? Me, I guess. I've gotta do it." Nick had already completed 6 Roadblocks, so if Vicki truly needed to do it, there would be a 6 Roadblock limit.
I'm starting to think though that there will not be a Roadblock on the final leg. We know teams work together on what appears to be the memory task and both team members perform the bungee drop (could be one of the detour options). From seasons 12 on, there hasn't been a Detour, Roadblock, and memory challenge in the final leg. Seasons 12 & 14, the Roadblock was the memory challenge. Season 13 there was no Roadblock. And Seasons 15 & 16 there was no Detour.