Evaluating the Congestion Relief Impacts of Public Transport in Los Angeles

Los Angeles has a complex multimodal transportation infrastructure, which includes, light rail and subway lines, bus lines, and an extensive freeway and road system. While transportation system provides several travel mode alternatives for commuters, this paper presents an assessment of the public transit services in a term of the congestion relief. This paper outlines a methodology developed to estimate the traffic congestion relief impact of public transit. An aggregated forecast model is used to predict congestion relief consequent on the road system and GIS mapping is used to illustrate the research results. The findings indicate the public transit service withdrawal has less impact on the outer suburbs of Los Angles. By contrast, it seems the Inner suburb and the areas buffer around Metro Lines are strongly affected. South Los Angles, Downtown, Korea Town, and Westlake are the areas with the highest share of mode shift to walk or bike. 8% of public transit riders are going to walk which increases the total number of people who walk to work by 19% (24,000) and only 3% of public transit users are going mode shift to bicycle. Also, the ratio of mode shift to car varies considerably by census tract and it is going to add around 267 thousand trips to the roads when 76% and 24% of commuters will drive alone and carpool; respectively. In total 89% of public transit users will choose to drive in the lack of public transportation.