Construction officially kicked off Tuesday morning on a project that aims to ease traffic congestion at the Grant Line Road-Highway 99 interchange.

Elk Grove city officials said the Grant Line Road interchange is one of the oldest still in operation on Highway 99.

Features of the new interchange project include:

- A partial cloverleaf with up to eight lanes on Highway 99 with two-lane offramps.
- A six-lane overcrossing that can be expanded to eight lanes.
- Metered onramps with high-occupancy vehicle, or HOV, lanes.
- New sidewalks and bicycle lanes.