As Streetsblog has been documenting, there has been a heavy cost to Measure R beyond a half cent increase to the county sales tax.

One of those costs that 20% of the collected funds will go towards massive highway expansion projects that will induce even greater car dependence, worsen air quality and promote sprawling development patterns.

Thanks to a recent article in the Santa Clarita Signal, we’ve been given a look at another one of those projects: The planned $500 million six lane widening of the I-5 from the Highway 14 interchange to Parker Road.  Construction could start within the next year.  The project will be completed in three phases and will add two truck-only lanes and a carpool lane in each direction.

Lest anyone wonder about the motivations for the project, Victor Lindenheim, executive director of the Golden State Gateway Coalition, makes it pretty clear.

“This is about adding capacity,” Lindenheim said. “When capacity is needed, in certain situations, it will be a godsend.”

Santa Clarita’s planning manager, Robert Newman, agreed.

“There’s certainly going to be a big benefit for traveling public,” Newman said.

If the theory that adding more travel lanes does nothing to improve traffic patterns over the long-term, the question for this project is the same as it is for other massive highway expansions.  Will the car congestion created by the expansion be greater than the “congestion savings” created by the expansion before the travel lanes are filled again.