Level of Service (LOS) is a measure of how much delay is at an intersection when the traffic a project is expected to generate is added to the surrounding area. In many cases, using the LOS methodology accommodates additional vehicles from projects by widening intersections and roadways. However, widening streets is shown to encourage even more cars on the street, often resulting in continued traffic congestion. Additionally, new developments are incentivized to locate in remote areas where there is little traffic congestion, which results in longer vehicle trips. More driving leads to greater greenhouse gas emissions. Furthermore, development in remote areas typically have a higher overall environmental footprint than infill development (i.e., development in already-developed areas).
Alternatively, VMT measures the amount of vehicle travel that would be generated by a proposed development based on the project characteristics and location. Factors such as high-quality transit and proximity to walkable, bikeable places are all contributing factors to reducing VMT. By establishing a VMT CEQA metric, projects will be required to reduce the amount of vehicle travel the project will generate and should result in less traffic overall and lower greenhouse gas emissions.