Environment
Chapter 6
This section examines emissions from September 2019 to August 2020 in the 2020 Public Annual Reports. It estimates carbon dioxide (CO2), a greenhouse gas that contributes to global climate change, and particulate matter of less than 2.5 microns (PM2.5) which contributes to respiratory health issues.
The Clean Miles Standard and Incentives Program (Senate Bill No. 1014) directed the CPUC to implement “annual targets and goals, beginning in 2023, for the reduction [...] of emissions of greenhouse gases per passenger-mile driven on behalf of a transportation network company”. The CPUC has issued an Order Instituting Rulemaking to determine how the Clean Miles Standard and Incentives Program will be implemented. The CPUC’s rulemaking follows work led by the California Air Resources Board (CARB), which developed a baseline inventory of TNC emissions and proposed initial annual targets and goals.
How much GHG did TNCs emit?
Greenhouse gases produced by TNCs will be regulated by the CPUC starting in 2023. Greenhouse gases are a key contributor to global climate change. Only Uber’s 2020 public TNC Annual Reports contain the data necessary to evaluate emissions (VMT and vehicle make, model, and year). Table 29 shows the estimated CO2 emissions produced by Uber per period.
TNC service is classified into 3 periods: Period 1 when a driver is available and ready to accept a trip, Period 2 when a driver has accepted a trip and is on the way to pick up the passenger, and Period 3, when a driver is transporting a passenger from origin to destination. CARB's 2018 Base Year Inventory found that TNCs emit 48% more greenhouse gases on a per-passenger mile basis than trips taken in private vehicles, due in large part to driving without a passenger in Periods 1 and 2. The Transportation Authority estimated that Uber emitted 494,000 metric tons of CO2 from September 2019 to August 2020, about 30% of which was produced in periods 1 and 2, when the vehicle is not transporting a passenger. Uber’s total CO2 emissions were similar to the CO2 emitted by the 2020 Caldwell Fire in northern California which burned 81,000 acres.12 Lyft emissions cannot be estimated because they did not report mileage, vehicle make, model, or year.
| Metric | Period 1 Waiting for ride request | Period 2 On the way to pickup passenger | Period 3 Transporting passenger | Total |
|---|---|---|---|---|
| Total CO2 | 85,408 | 61,523 | 346,790 | 493,722 |
| Share of CO2 | 17% | 12% | 70% | 100% |
How much particulate matter (PM 2.5) did TNCs emit? Where?
PM2.5 contributes to respiratory health issues. Only Uber reported the data necessary to evaluate PM2.5 emissions. Table 30 shows estimated PM2.5 emissions produced by Uber. Uber produced 2.65 metric tons of PM2.5, about 30% of which was produced in Periods 1 and 2 when the vehicle is not transportation a passenger. Lyft’s PM2.5 emissions cannot be estimated because they did not report mileage, vehicle make, model, or year.
| Metric | Period 1 No passenger, waiting for ride request | Period 2 On the way to pickup passenger | Period 3 Transporting passenger | Total |
|---|---|---|---|---|
| Total PM2.5 | 0.46 | 0.32 | 1.87 | 2.65 |
| Share of PM2.5 | 17% | 12% | 71% | 100% |
Figure 21 shows where Uber emitted PM2.5 by county for the 10 counties with the most TNC trips. PM2.5 emissions were highly concentrated in San Francisco with over 5,000 grams of PM2.5 per square mile, approximated 340 times the concentration of PM2.5 emissions in the rest of the state. Uber’s estimated PM2.5 emissions in San Francisco are approximately 5% of the total PM2.5 emissions produced by all passenger vehicles and light duty trucks in San Francisco in 2019.3
Emissions were estimated individually for each trip, using the vehicle make, model, and year, mileage by period, and emissions rates from fueleconomy.gov ↩︎
California Air Resources Board, Wildfire Emission Estimates for 2020. ↩︎
CARB EMFAC2021 v1.0.2, PM2.5_TOTEX for LDA, LDT1, and LDT2 in San Francisco in 2019. ↩︎