Tolling on the State Route 520 bridge may not begin until June because of the difficulty of integrating multiple new pieces of technology.

The Washington State Department of Transportation is employing new technology to read license plates with cameras and link them to individual accounts for drivers who use the bridge consistently. Testing and integrating the technology has taken longer than originally expected.

Tolling is expected to pay for at least $1 billion of the $4.6 billion project. The project is still nearly $2 billion short of having the needed financing.

Tolls on the bridge would vary by time of day with the most expensive rates ($3.50 each way for Good-to-Go transponder users, and $5 for everyone else), coming during commuting hours of 7-9 a.m. and 3-6 p.m.

Tolling was originally supposed to begin in mid-April.