LOS ANGELES (CBSLA) — A new study shows that Los Angeles has the worst gridlock in the world. Another new study demonstrates that Southern Californians are shunning one potential solution to LA’s traffic woes — public transit.

The Southern California Association of Governments (SCAG) report finds that transit use in Southern California has declined significantly over the past ten years as car ownership has increased.

From 2012 to 2016, Southern California lost 72 million transit riders per year. The drop in ridership comes at the same time that Los Angeles County is rapidly building out its mass transit system.

More than 100 miles of light and heavy rail have been added to Los Angeles County over the last 25 years, and 530 miles of commuter rail across the six-county SCAG region.

The study concludes that as long as driving remains cheap, Southern Californians will continue to choose private cars over public transit.

“The large subsidies given to transit in recent years pale next to the longstanding subsidies for automobiles that are hidden in unpriced road use, unpriced or underpriced street parking, high minimum parking requirements, and taxpayer- and developer-financed road-widenings,” the report states. “If public policy does not adequately confront underpriced driving, then transit ridership will likely continue to falter, and transit will not meet its ambitious environmental goals.”