"It'll turn red whenever you have an aircraft attempting to depart and an aircraft attempting to cross the runway," said Jim Crites, D/FW's executive vice president of operations.
Two ground radar systems interact with a computer system to turn lights on and off at the right time or to shut them off if no plane is on the runway.
Nationwide, the Federal Aviation Administration continues to focus on preventing close calls on runways. The National Transportation Safety Board still considers so-called incursions a top safety concern.
The runway lights are for the rare instances when a pilot and an air traffic controller miscommunicate or make a mistake. They won't replace the crucial communication between a pilot and an air traffic controller, said Allen Parra, D/FW's vice president of operations.
D/FW had seven incursions in 2001, 2003 and 2004 and two in 2002. The last incursion at D/FW that got the government's most dangerous rating was in May 2001.
The test, which runs through May, is also being conducted at San Diego International Airport.