Football's rule-makers have approved in-game trials with video assistance for referees as Gianni Infantino used the start of his FIFA presidency to push innovation in the sport.
Initially tests will be in private before moving to a live pilot phase with replay-assistance by the 2017-18 season at the latest, the International Football Association Board's annual meeting decided on Saturday.
The IFAB will have to approve all trials, with 13 leagues or associations already expressing an interest in hosting trials.
Infantino is keen to show that FIFA has embraced a "new era" with the reign of his predecessor Sepp Blatter now over.
"We have taken really a historic decision for football," Infantino said in the Welsh capital, Cardiff. "FIFA and IFAB are now leading the debate and not stopping the debate. We have shown we are listening to the fans, the players."
IFAB rejected allowing coaches to have appeals where videos of incidents could be examined.
What will the video assistance experiments approved by The IFAB look like? Find out here - https://t.co/KigxzNI2gE pic.twitter.com/juLEVuDQK9
- FIFA Media (@fifamedia) March 5, 2016
The use of video would be restricted to referees ruling on whether a goal has been scored, a penalty should be awarded, a player should be sent off or in cases of mistaken identity.
It is four years since IFAB approved the introduction of technology to determine whether the ball crossed the line.
The statement released by FIFA said: "The expectation is not to achieve 100 percent accuracy in decisions for every single incident, but to avoid clearly incorrect decisions that are pre-defined 'game-changing' situations -- goals, penalty decisions, direct red card incidents and mistaken identity.
"The IFAB agreed to allow one type of experiment, which will involve a video assistant referee having access to video replays during the match and either reviewing an incident on request by the referee, or communicating with the referee proactively about an incident that he/she may have missed."
The IFAB also approved an amendment to the controversial "triple punishment" situation, whereby a player can be sent off, concede a penalty and be suspended when denying an obvious goal-scoring opportunity in the penalty area.
It said it had unanimously approved a new wording for Law 12, whereby players would instead be given a yellow card in instances where the referee awards a penalty for denial of a clear goal-scoring opportunity.
However, the ruling decrees that players will still be sent off should the offence be holding, pushing or pulling; not involve a genuine attempt to play the ball or have a realistic chance of playing the ball; or if the incident would result in a red card were it to occur elsewhere on the field (such as violent conduct).
Alteration to Law 12 (on 'triple punishment') approved by IFAB for 2 year trial: https://t.co/8j4vAbLI6c pic.twitter.com/ENYZlnfjX2
- FIFA.com (@FIFAcom) March 5, 2016
The IFAB is also to "allow experimentation with a fourth substitution in extra time," although it has yet to decide where the trials will take place.
The statement explained: "The aim will be to see whether there is player welfare benefit, whether the fourth substitute is used tactically or genuinely for player welfare and whether the potential use of all four substitutes during extra time (and thus change more than a third of the team) has an unfair impact."