Project Summary
Problem Statement: To reduce carbon emissions as part of AB 32, California has implemented cap-and-trade policies that raise the price of diesel fuel. The increase in fuel cost provides an incentive for shippers to maximize truck loading and increase total truck weight, which generates more road damage. No prior studies have quantified these damages.
Proposal: UC Irvine researchers will use the state’s 1.2 billion data points on truck weight to quantify the effects of diesel prices on vehicle weight and road damage. Using sophisticated statistical analyses, the relationship between diesel prices and vehicle weight from other potentially confounding factors such as GDP growth and trends will be disentangled. While preliminary state-level analysis has been completed, this research will drill down into these results identify where in the state the effects are most pronounced, to better classify the types of vehicles on the road and their relative contributions to road damage, and to increase the sophistication of our policy simulations. Much of this requires better decoding of the data to fully describe the vehicles in the data. Analysis will be performed detector by detector to enable a characterization of effects based on the proximity to, for example, urban/agricultural areas, intermodal facilities, and ports.
Expected Impact and Benefits: This research will provide policymakers with information on the effects of fuel taxes on roadway damage that can be considered in taxing and funding decisions. Preliminary results suggest that for a given diesel tax increase, 10 percent of the revenue is eroded by increased infrastructure damage. Conversely, because efficiency standards on trucks reduce per-mile costs, they serve as an incentive to down-weight vehicles.
Simple simulations reveal that over a wide range of parameters, a given level of carbon emissions and oil use reductions are more efficiently achieved through fuel efficiency standards than through diesel taxation. This suggests that the optimal policies to reduce carbon from freight trucks, one of the least-regulated carbon emitting markets, are likely to be different than that for automobiles. Furthermore, because trucks are responsible for nearly all user damage to highways, freight truck policy has the potential to generate large, unanticipated costs for agencies responsible for maintaining roads.
