The USGA has changed the US Open playoff format moving forward in 2018 and beyond, ending the tradition of an 18-hole playoff the day after 72 holes is completed to a two-hole, aggregate-score playoff which begins immediately after play ends (assuming it's feasible).
Not only will the US Open have a two-hole, aggregate-score playoff, but the playoff format for the US Women's Open, US Senior Open and the new US Senior Women's Open, which starts in 2018, will have the same playoff format.
There have been 33 playoffs in US Open history. The last time there was a US Open playoff was in 2008, when Tiger Woods defeated Rocco Mediate in 19 holes to win his 14th major title. Prior to that, the last playoff was in 2001 at Southern Hills, when Retief Goosen won.
The US Women's Open and US Senior Open had previously used a three-hole, aggregate-score playoff format to break ties. In 2016, Brittany Lang defeated Anna Nordqvist at CordeValle by three strokes in extra holes for her first major title. That championship's first playoff in the now prior format was 2011.
In 2014, Colin Montgomerie defeated Gene Sauers in a three-hole playoff at Oak Tree National. This format debuted in 2002 in the Senior Open.
The change was made, in part, in the interest of crowning a champion on Sunday -- something expressed by fans, players, TV partners and others.
“There is no right or wrong way to determine a winner in stroke play, but we’ve seen over the years how the aggregate playoff has served us well in both the U.S. Women’s Open and U.S. Senior Open,” said USGA Executive Director and CEO Mike Davis. “Two holes will allow a player to recover from any single mistake, and at the same time, provide a memorable, and perhaps dramatic, experience for all involved.”