Study from Ramboll Underscores Economic Risks and Limited Environmental Benefits of Indirect Source Rules
SACRAMENTO, CA — A major updated analysis is raising red flags about a new air quality regulatory approach— finding that such regulations are driving up costs without delivering meaningful emissions reductions.
As policymakers across the country consider new air quality regulations, the updated analysis from Ramboll reinforces a clear conclusion: so-called “Indirect Source Rules” (ISRs) are a costly, complex, and bureaucratic solution that produces limited emissions reductions.
Indirect Source Rules (ISRs) regulate facilities for emissions they do not directly control — attempting to shift behavior across third-party trucking fleets rather than reducing emissions at their source.
The updated findings, based on a program implemented by California’s South Coast Air Quality Management District (AQMD), confirm earlier analysis: high costs with little to no environmental benefit.
“The updated analysis makes clear that expanding ISR policies would export higher costs and operational disruption nationwide — without delivering the environmental results policymakers are trying to achieve,” said Tim Jemal, CEO, Supply Chain Federation. “Government agencies contemplating this type of regulation should pause and review alternatives that deliver clear environmental benefits.”
Why it matters: South Coast AQMD’s Warehouse Actions and Investments to Reduce Emissions (WAIRE) program has become the leading test case of ISRs. But both independent research and regulator-led analysis are raising serious concerns.
A technical assessment from the San Diego County Air Pollution Control District found ISR-style rules would likely deliver smaller emissions reductions than other strategies, while imposing significantly higher costs. The analysis also questioned whether such policies effectively target the communities most impacted by pollution.
At the same time, the updated Ramboll analysis confirms WAIRE has not achieved meaningful emissions reductions, even as compliance costs continue to rise — especially for smaller operators.
The big picture: ISR-style policies are gaining traction beyond California.
In Illinois, SB 3732 and HB 5600 would establish a statewide warehouse emissions reduction program in the form of ISRs
In New York, S.1180B (Gianaris) and A.3575B (Mitaynes) are being considered, with similar policies under consideration by New York City.
What’s working instead: Many regulators and industry leaders are focusing on infrastructure and technology — widely seen as the real drivers of emissions reductions.
In Southern California, the Port of Los Angeles and Port of Long Beach are trying an alternative to ISRs, partnering with the South Coast Air Quality Management District to scale zero-emission infrastructure, including charging and fueling systems.
Since requiring heavy-duty diesel trucks to be certified to 2010 standards or higher, many Southern CA regions have seen a 98% reduction in diesel particulate matter (DPM).
What’s next: In California, AB 1777 (Garcia) would authorize the California Air Resources Board to expand ISR-style regulations statewide.
“Everyone shares the goal of cleaner air and healthier communities,” Jemal said. “But the updated data is clear — this approach raises costs, risks jobs, and fails to deliver. We need solutions grounded in infrastructure, technology, and real-world results.”
Resources:
Read the updated analysis.
Review the summary.
Review the factsheet.
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