here's some info on the different "obsticles"
Switchback
The Switchback, introduced in Season 15, is a task from a previous season that is revisited and that the teams must complete. For the Switchback in Season 15, teams revisited the infamous Stockholm Roadblock from Season 6, except it was made more difficult by having to find just one of seven flags in 186 hay bales, where previously teams had to find one of 20 clues in 270 hay bales.
[edit] Yield
The Yield, introduced in Season 5, allows any one team to force another team to stop racing for a predetermined amount of time. The Yield marker is placed near a Route Marker, and teams would be forced to stop at it to state their intentions to employ the Yield. The clue would say "Caution: Yield ahead!" If a team Yielded another team, they would place a photo of the Yielded team, along with a "Courtesy Of" photo of themselves, on the stand. When the Yielded team arrived at the Yield, they would then turn over an hourglass and wait for the sand to drain before they can continue to the Route Marker. A team may only use their Yield power once on the race, and only one team may be Yielded when the Yield is available, though the same team can be Yielded multiple times during the same Race. If a team loses their "Courtesy Of" photo, they lose their Yield power.[9][10] If the team that is Yielded has already passed the Yield, the Yield is nullified.
During Season 5, teams were not aware of the upcoming Yield. In subsequent seasons, clues have alerted teams that a Yield would be present at the next route marker. Yields were present in every leg except the last of Season 5, while only three were present in Seasons 6 through 8, and two in Seasons 9 through 11. Yields have not been present in the US Race since Season 11, but are still present within the foreign editions.
[edit] U-Turn
The U-Turn, introduced in Season 12, is similar in format to the Yield; however, it is always placed immediately after a Detour. After completing their Detour option, a team may use their U-Turn ability to force another team to backtrack and complete the Detour option they did not previously complete. Like the Yield, the team placing the U-Turn places a photo of the team they are penalizing along with their own "Courtesy Of" photo on the U-Turn marker stand. Starting in Season 14, teams were met with a new variation of the U-Turn called a "Blind U-Turn." If teams use a Blind U-Turn, they do not have to publicly reveal themselves as the perpetrators with their "Courtesy Of" photo. Like the Yield, if the team has lost their "Courtesy Of" photo, they will be unable to use their U-Turn power for the remainder of the Race,[11] It is possible for a team to U-Turn a team that has already passed the U-Turn, nullifying its effects. A team can only use their U-Turn power once per Race, regardless if they don't have to use their "Courtesy Of" photo for the "Blind U-Turn", and only one team may be affected by the same U-Turn during a leg. Teams are warned of an upcoming U-Turn on or the Route Marker after the Detour clue. Season 15 was the first and only season not to air a U-Turn.
[edit] Intersection
The Intersection, used in Seasons 10, 11, and 16, requires each team to pair up with one other team and perform all tasks and make decisions together until further notice. Should there be no other teams present when a given team arrives at the Intersection route marker, they must wait there until another team arrives, though they do not have to partner with that team and can opt to wait for another team instead. Teams are free to choose their partner team if multiple teams are present. Teams are not warned when an Intersection is coming. Route Markers for Detours, Roadblocks, and Fast Forwards have been included with the use of the Intersection.
