As Carter mentioned in the headlines this morning, another national study has been released — by the traffic navigation services firm Inrix — that shows that the Los Angeles metro area has the worst traffic in the United States.

In particular, the study singled out three stretches of freeways in Los Angeles County as ranking in the top 10 for delays during the afternoon rush hour: The northbound 405 between the 105 and Getty Center Drive; the southbound 5 freeway between downtown L.A. and Orange County; the eastbound 10 freeway between downtown L.A. and Baldwin Park, and; the eastbound 10 freeway between Santa Monica and downtown L.A.

None of this should be surprising news to local motorists. And I don’t expect traffic in those corridors to vanish as long as there are jobs on one end of them and homes on the other.

That said, I do think it’s worth pointing out that Metro is involved in projects in each of those corridors that could help improve traffic flow or provide transit alternatives:

•A carpool lane is currently under construction on the northbound 405 between the 10 freeway and the 101 freeway as part of the I-405 Sepulveda Pass Improvements Project that will also upgrade interchanges in the area.

•A project to widen the 5 freeway between the 605 freeway and the Orange County Line is planned to be built in six phases between now and the end of 2016. The first project — improvements to the I-5/Carmenita Road interchange, will begin construction this July and three more phases are scheduled to begin construction in the next two years. The Measure R sales tax increase approved by voters in 2008 is contributing money to the widening with Caltrans as the lead agency.

•Metro is currently planning the ExpressLanes project, which will add a second carpool lane in both directions to the 10 freeway between Alameda Street in downtown L.A. and the 605 freeway and will also allow solo drivers to use those lanes in exchange for a toll.

•As for the Santa Monica Freeway, three major transit projects to better connect the Westside to downtown L.A. — and thereby the rest of the area’s transit network — are underway. Construction of the first phase of the Expo Line between downtown L.A. and Culver City is almost complete and the second phase extending the line to Santa Monica should soon be underway. Metro is also in the planning stage for a peak hour bus lane on parts of Wilshire Boulevard within the city of L.A. and the Westside Subway Extension is deep into its environmental study phase. The federal government also recently gave Metro the green light to advance the project into its preliminary engineering phase.