“The variety of companies that showed an interest in goal-line technology in soccer ranged from somebody inventing things in his garden shed to large multinational companies who have spun out from military technology, from ballistics tracking systems,” said Dr. Andy Harland, director of the Sports Technology Institute at Loughborough University in Great Britain, who counseled some of the companies that submitted proposals.

“FIFA ended up getting some of the finest minds from around the world focusing their attention on how we can solve the problem of goal-line technology in soccer. What is clear to me is that no sport has the capacity to solve all of its problems within the sport.”

While Hawk-Eye and GoalRef demonstrate that reliable goal-line technology is possible for soccer, developing goal-line technology for football is a more complicated and potentially more costly problem.

The NFL has looked at sensors in footballs to assist with goal-line calls for years, but Aiello said, “There just hasn’t been a solution that anyone feels works.”

In the NFL, body parts cross the goal line repeatedly and can conceal the ball on a scoring play. Plus, a player must have possession when he crosses the line, and technology struggles with subjective decisions such as ball control.

“When we’re getting into more complex things like determining ball possession, I think we’re a ways away from technology being able to make some of those calls and get it right,” said Blair, who is also director of the Cooper Perkins sports engineering group. “The nuances of the NFL game can make it difficult.”

As a result, any new NFL officiating technology likely will address more straightforward aspects of the game. Green anticipates that officials will communicate wirelessly in the not-too-distant future, eliminating the wait while referees sprint downfield to huddle with their crew members.

Off the field, video technology is a valuable training tool, allowing officials to review a greater volume of calls and player tendencies between games. Green hopes there will be continued technology upgrades in the training department.

When asked if the NFL would consider technological assistance for calling first downs and marking the line of scrimmage, Aiello said, “As technology evolves, we’ll certainly be looking at it and we’re open to it. Innovation is one of our core values.”

That said, the NFL believes its current use of instant replay is particularly effective, helping officials with the toughest calls while generally not distracting from the game.

When it comes to the NFL and other popular sports, engineers, league officials, and referees agree that new technology succeeds only when it improves both the accuracy of calls and the game experience for fans.

“If the game becomes too mechanistic, if there’s no room for interpretation, then suddenly there’s no room for supporters,” said Harland.

Also, if technology disrupts the flow of the game, it doesn’t succeed.

When the NFL adapted instant replay from broadcasts to official use in 1986, the technology initially fell flat with fans because it caused lengthy delays.

“Technology can be helpful, but it shouldn’t be overbearing and intrude on what makes the game great,” said Green, who has been an NFL official for 22 years. “You don’t want to be watching some guy in a spacesuit running around, trying to look through goggles and make decisions.

“It’s still a game played by humans and coached by humans and officiated by humans. There’s a certain element that’s never going to be perfect.

“You can work to make improvements, but you don’t want to take away from what makes it the most popular sport in America. Putting on goggles and running around the field seems pretty extreme to me.”