A push to rebuild the airport's southern runway system is the latest in a four-year effort by the city agency that operates LAX to solve the seemingly intractable problem of near misses at the 40- year-old airfield.

LAX is particularly prone to near misses because its airfield wasn't built to handle today's larger aircraft, and the runways don't meet an FAA requirement that they be at least 1,000 feet apart.

About 80% of the near misses at LAX over the last three years occurred on the south airfield when an aircraft taxiing from the outer runway to the terminals came too close to an airplane taking off on the inner runway. Aircraft take off at LAX on the inner runways to shield nearby neighborhoods from noise.