ROSEVILLE, Calif. -- Many communities are getting a new report card today that grades just how effective their traffic signals are.

In the meantime, one local city is already taking steps to improve its traffic signal operation.

The federal government estimates every year drivers waste a total of 330 million hours sitting at poorly timed traffic lights.

In fact -- a national traffic signal report card released this morning shows the country as a whole only gets a "D."

In Roseville -- the city got a "C" from the National Transportation Operations Coalition when the last report card came out in 2005.

But this time it's getting a "B -" thanks to a $2 million technological upgrade.

Much of that money has gone to converting about a third of Roseville's traffic lights into what are called "smart traffic lights," such as the one at the corner of Sunrise and Douglas.

KCRA 3 talked with the head of traffic services in Roseville and asked him what exactly is a smart traffic light.

Jason Shykowski said a smart traffic light is one that can sense the number of cars at the intersections, tell you how long the line is, and can sometimes make timing adjustments.

Here's the way traffic lights used to be adjusted.

Engineers would sit at intersections, observe the traffic flows, then go out an manually adjust the timing at the light.

Back then -- they could only adjust each light every few years. Now they can constantly make adjustments.