As any savvy business owner in the U.S. knows by now, just because an environmental regulation is implemented by California doesn't mean it won't impact operations outside the Golden State.

In few industries is this truer than trucking — and for two reasons. First off, trucks are, of course, mobile and California applies its green rules to whatever commercial vehicles cross its border, even if only once or for a few miles at best. Secondly, California's regulators have become trendsetters. The rules they promulgate, especially environmental regulations, are duplicated by other states and as often as not result in de facto national standards for motor vehicles.

That's why when it comes to 2010 engines, everyone in trucking must pay attention to a critical new regulation adopted in December by the California Environmental Protection Agency's Air Resources Board, a.k.a “ARB” in the state and “CARB” outside of it.

To be effective, commencing Jan. 1, 2011, the Statewide Truck and Bus rule will require nearly all truck owners who operate in the state to install diesel exhaust filters on their vehicles by 2014 — and here's the big kicker — to replace engines older than the 2010 model year between 2012 and 2022, via a staggered implementation schedule.

The rule was passed alongside another, the Heavy Duty Vehicle Greenhouse Gas Emissions Reduction measure, which will require long-haul truckers to use “fuel-efficient tires and aerodynamic devices on their trailers that lower greenhouse gas emissions and improve fuel economy.”

CARB said the state will offer over $1 billion in funding to help fleets upgrade their vehicles per both rules. These options will include Carl Moyer grants (designated for early or surplus compliance with diesel regulations); Proposition 1B funds (for air quality improvements related to goods movement); and the state's AB 118 rule, which establishes a low-cost truck loan program for early compliance with the truck rule.

“[This] vote marks a milestone in the history of California's air quality,” says CARB Chairman Mary Nichols. “The Board's actions will not only help protect the health of 38 million Californians, they will also ensure that California continues strongly on its path to achieving clean air.”

The agency says it is providing flexibility by structuring the diesel rule with different “compliance options”: Fleets with three vehicles or less are exempt from any of the requirements until 2012. Starting in 2012, they would have to clean up one vehicle but would not have to meet the 2010 engine requirements until 2018.

There are also flat-out exceptions to the reg, including for “low-use vehicles” as well as emergency and military vehicles and personal-use motor homes. School buses will be subject to the filter requirement but not engine replacement.

According to CARB, heavy-duty trucks are responsible for 32% of smog-forming emissions and 40% of cancer-causing emissions from diesel mobile sources. It claims the new regulations will reduce diesel emissions by 68% and NOx by 25% by 2014, saving 9,400 lives and reducing health-care costs for an estimated public value between $48 billion and $69 billion.

CARB says the total cost of the two regulations will be approximately $15.9 billion. However, it says the truck regulation's $5.5 billion price tag would be spread over 16 years.

The agency has admitted the cost to fleets with newer vehicles in service will be minimal, while fleets that need to upgrade a significant number of vehicles will find the cost to be “significantly more substantial.” CARB says it expects businesses will pass the compliance costs onto their customers.

The diesel rule is expected to impact about 900,000 vehicles, including about 400,000 registered in the state and some 500,000 that do business in California, notes CARB.