Tolling on State Route 520 across Lake Washington will start in December, the Washington State Department of Transportation announced last week.

Tolling on the bridge was set to begin this past spring.

“It has been no secret that we’ve had challenges getting this system up and running, and the work has been more difficult than we anticipated,” said WSDOT Deputy Secretary David Dye.

Much of the issue comes with the fact that the system planned for SR-520 has never been implemented before. While none of the features are new, they have never been aggregated before.

“Electronic tolling already exists, photo tolling already exists, but we’re taking the best of everything and putting them into one system,” a press release said.

The system is expected to track and handle more than 100,000 daily transactions on the SR-520 bridge. The tolls will be captured either through Good To Go windshield stickers or through license-recognition photos, which automatically generate a bill that is mailed to drivers.

Tolling on SR-520 is expected to raise $1 billion overall toward the $4.65 billion SR-520 bridge replacement.