For the second time this week, technical problems slowed traffic at Dallas/Fort Worth International Airport's new toll plazas.
The exit on the north side of the airport backed up because of overall slowness with the computer system, which affected every transaction, including TollTags, credit cards and cash.
Airport engineers are investigating the issue but do not yet know what caused the slowdown.
Employees manually opened the gates to get drivers out. The slowdown coincided with the airport's busy time, which added to the congestion.
Workers also manually lifted the gates for drivers on Monday, when the computer system had trouble reading TollTags throughout the day.
The parking toll plazas also had issues soon after they opened in early September. Potentially thousands of drivers were overcharged last month because of technical problems with the TollTag readers.
In addition to the slowdown, two lanes on the north exit were not operating Wednesday, but it was not related to the technical problems, the airport said.
NBC 5's Eric King contributed to this report.