TRANSPORTATION RESEARCH RECORD 1520 53 Emissions Analysis of Southern California Metrolink Commuter Rail MATTHEW J. BARTH, THEODORE YOUNGLOVE, AND RAMAKRISHNA R. TADI The Southern California Regional Rail Authority began constructing a The purpose of this research project is to estimate total pollutant new commuter rail system called Metrolink in October 1992. When emissions associated with a single Metrolink line, specifically the complete, the Metrolink system will form the nation’s sixth largest Riverside line. The Riverside line, which began operation in 1993, commuter rail system and is expected to alleviate congestion and help runs from downtown Riverside and continues to downtown Los obtain better air quality. To estimate the air quality impact, emissions Angeles Union Station (LAUS) with stops in Pedley, East Ontario, of CO, HC, NOx, and PM associated with an automobile-only–based commute and a Metrolink-based commute from Riverside to Los and the city of Industry. In this study, emissions associated with Angeles are compared. Analysis of the Metrolink-based commuting two commuting scenarios are compared. An emissions estimation scenario includes the emissions from the home-to-station automobile is first made for commutes from Riverside to downtown Los Ange- trip and the Metrolink diesel locomotive emissions. Essential data for les using the Metrolink system. This is then compared with the the automobile emissions modeling process were obtained through a emissions associated with the same set of commutes made by auto- survey of Metrolink passengers and through remote emissions sensing of Metrolink passenger vehicles. Train emissions were estimated using mobile. On the basis of trip conditions recorded in November 1994, emission rate data provided by recent diesel locomotive studies. this study attempts to predict the minimum amount of Metrolink Results indicated that at current ridership levels there is a reduction in ridership required to get a net emissions reduction from the system. total amount of all four pollutants combined through Metrolink com- Several key emission sources were identified and incorporated muting. On a pollutant-by-pollutant basis, it was estimated that the into this analysis. Two components were estimated for the Metrolink Metrolink commuting scenario reduces the emissions of CO and Riverside to LAUS commute: cold start and running emissions of HC relative to the automobile-only commuting scenario; however, it automobiles during the home to Riverside Metrolink station trip and increases the emissions of NOx and PM. The minimum amount of Metrolink ridership required to get a net emissions reduction from the running emissions of the diesel locomotive traveling from Riverside system is predicted. to LAUS. For the non-Metrolink-based trip scenario, cold start and running emissions of automobiles were estimated for the Riverside to downtown Los Angeles commute. The South Coast Air Basin, which makes up major portions of Los Ridership and vehicle data were collected through a survey that Angeles, Orange, Riverside, and San Bernardino counties, is a was conducted simultaneously with a remote sensing emissions major air pollution nonattainment region and is projected to be for experiment at the Riverside Metrolink station. This data collection the foreseeable future. Strict regulations on emissions have been process is described in more detail in a later section. Emission data imposed on everything from lawn mowers to major factories. for the Metrolink diesel locomotives were obtained from recent Numerous emission-cutting programs have been initiated to technical reports produced for the SCRRA (2) and the Southwest improve the air quality (e.g., telecommuting and ride-sharing). As Research Institute (SwRI) (3). Cold start emissions and running another major program to alleviate traffic congestion and obtain emissions for automobiles were based on the EMFAC7F emissions better air quality, the Southern California Regional Rail Authority model developed at the California Air Resources Board (4). For this (SCRRA) began constructing a new commuter train system called study, four emission species are considered: carbon monoxide Metrolink in October 1992. There are currently five lines in opera- (CO), hydrocarbons (HC), oxides of nitrogen (NOx), and particulate tion: the Riverside Line, San Bernardino Line, Santa Clarita Line, matter (PM). Ventura County Line, and the Fullerton Line, as shown in Figure 1. It is important to point out that this study is done purely from an The system is still expanding and when complete Metrolink will air quality standpoint and does not deal with operating cost and rev- form the nation’s sixth largest commuter rail system, with con- enue aspects of Metrolink or traffic congestion and stress aspects of struction costs more than $500 million (1). Metrolink commuter the automobile commuters. Further, the comparisons are made only trains connect suburban communities with centers of business, such for the single Riverside Metrolink line for commuters traveling from as Burbank, Glendale, Industry, and downtown Los Angeles. The the Riverside area to LAUS, and the conclusions may not necessar- SCRRA monitors the passenger ridership counts of each line ily be applied to the entire Metrolink system. Vehicle age and loco- closely, from which the amount of congestion mitigation can motive power settings and travel times are critical in assessing the be determined (2). However, there have been no detailed studies on automobile and rail emissions and may vary significantly for other the direct air quality impact of Metrolink since its inception. lines. Background information on Metrolink’s Riverside line is first provided with a description of the data collection process performed College of Engineering, Center for Environmental Research and Technol- for this study. This is followed by a summary of various trip statis- ogy, University of California, Riverside, Calif. 92521. tics derived from the data collection phase. The methodology is then 54 TRANSPORTATION RESEARCH RECORD 1520 FIGURE 1 Southern California’s Metrolink commuter rail system (source: SCRRA). given with the results of the emissions analysis. Finally, the last Passenger Survey Data section presents various conclusions from the study. Ridership travel characteristics along the Metrolink’s Riverside line were obtained through a passenger survey conducted during a typ- ical weekday (Wednesday, November 16, 1994). The data collected METROLINK: RIVERSIDE LINE during the survey included The downtown Riverside Metrolink Station is located on approxi- • Trip origin/destination/purpose information; mately 11 acres in the Marketplace redevelopment area in River- • Length, time, and mode of home-to-Riverside Metrolink side, California. The Riverside County Transportation Commission station trip; (RCTC) maintains and operates the station. The station consists of • Model year and make of vehicle used to travel to Riverside a dual-sided platform and parking for 390 automobiles. At the time Metrolink station; of the data collection for the study, six commuter trains between • Trip length, time, and mode of drop-off station to final destina- Riverside and Los Angeles served the station, along with Amtrak tion; and connecting buses, and Riverside Transit Agency feeder bus service. • Miscellaneous information such as reason for choosing rail, For this study, only a.m. peak period commuting trips have been prior travel mode, and so forth. considered. These trains leave at 5:00 a.m., 6:10 a.m., 6:43 a.m., and 7:35 a.m., from the Riverside station. The average duration of these A total of eight people (four staff and four students) conducted the morning trips between Riverside station and LAUS is approxi- passenger survey in cooperation with SCRRA and RCTC. Blank mately 1 hr and 8 min, with the trains operating at speeds ranging survey forms were distributed by two students to all passengers from 25 to 60 mph (40 to 96 kmh) [maximum speed is 75 mph boarding the Metrolink at the Riverside Station for departures at (120 kmh)]. 5:00, 6:10, 6:43, and 7:35 a.m. These same students also boarded the train and traveled to the East Ontario station to answer any ques- tions the passengers may have had about the survey questionnaire. The completed survey forms were collected before disembarking in METHODOLOGY: DATA COLLECTION Ontario. Those passengers who could not or did not want to com- plete the forms on board the train and wished to complete the forms To evaluate and compare total pollutant emissions, two different at a later time were given self-addressed stamped envelopes. commuting trip scenarios have been considered: (a) Metrolink- Out of a total of 362 survey forms that were distributed to adult based commute trips and (b) automobile-only commute trips. To passengers who boarded the four morning trains (outbound to Los perform this analysis, various data were collected. Angeles) at the Riverside Metrolink Station, 297 (82 percent) pas- Barth et al. 55 sengers completed the survey. This includes 9 of the 15 distributed mailback survey forms. The information gathered in the surveys not only provided origin and destination information needed by the emission models, but also helped to establish vehicle mix profiles and a probability density of cold start emissions modes. A more detailed analysis of the data and the emission results are presented in subsequent sections. Remotely Sensed Emissions Data Remote sensing emissions instrumentation was set up on