The Department of Energy?s (DOE) Vehicle Technologies Office funds research on development of technologies to improve the fuel economy of both light- and heavy-duty vehicles, including advanced combustion systems, improved batteries and electric drive systems, and new lightweight materials. Of these approaches to increase fuel economy and reduce fuel consumption, reducing vehicle mass through more extensive use of strong lightweight materials is perhaps the easiest and least expensive method
however, there is a concern that reducing vehicle mass may lead to more fatalities. Lawrence Berkeley National Laboratory (LBNL) has conducted several analyses to better understand the relationship between vehicle mass, size and safety, in order to ameliorate concerns that down-weighting vehicles will inherently lead to more fatalities. These analyses include recreating the regression analyses conducted by the National Highway Traffic Safety Administration (NHTSA) that estimate the relationship between mass reduction and U.S. societal fatality risk per vehicle mile of travel (VMT), while holding vehicle size (i.e. footprint, wheelbase times track width) constant
these analyses are referred to as LBNL Phase 1 analysis. In addition, LBNL has conducted additional analysis of the relationship between mass and the two components of risk per VMT, crash frequency (crashes per VMT) and risk once a crash has occurred (risk per crash)
these analyses are referred to as LBNL Phase 2 analysis.