California’s clean truck and bus incentive program was designed to expand the zero-emission vehicle market and improve air quality in heavily polluted communities.

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But the $1-billion program has been roiled by allegations of fraud, waste and poor oversight.

Although state officials insist California’s clean truck and bus subsidy program has helped reduce air pollution and planet-warming gases, a Times investigation found that those claims rely heavily on assumptions and estimates, instead of actual data.

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Some state-funded trucks and buses were rarely driven due to issues with vehicle performance and maintenance. In at least one case, California paid nearly $1 million in public funds for “vehicles that did not exist,” according to court records.

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