Exposure to particulate matter (PM) presents a great threat to human health and transportation is a major contributor to PM globally, in the U.S., and in California. In an attempt to reduce the PM burden that heavy-duty (HD) trucks impose on human health, California has implemented new, more stringent emissions standards. However, these standards remain challenging to enforce. This is partially due to the high direct costs of monitoring mobile polluters’ emissions, which have proven to be a substantial impediment to achieving compliance.
The purpose of this study is to examine the effectiveness of two new enforcement methods of increasing compliance of high-emitting HD trucks with California’s emissions regulations. In partnership with the California Air Resources Board (CARB), our study will use new remote sensing technology, the Portable Emissions Acquisition System (PEAQS), to detect black carbon emissions of HD trucks as they drive on the road. We will use PEAQS readings to identify high-emitting trucks most likely to be in violation of California emissions regulations and will conduct our randomized controlled trials (RCTs) with this set of trucks as the sampling frame. Each truck will be randomly assigned either to the control group, or to receive one of two enforcement strategies that differ in cost and severity: 1) a low-cost, low-severity letter intervention targeted at a single high-emitting truck and 2) a high-cost, high-severity audit intervention covering a truck’s entire fleet.