One Light, Two Light, Red Light, Green Light: An Analysis of Signal Priority on the Metro G Line
- Author(s): Hwang, Yu Hong
- et al.
Los Angeles County Metropolitan Transportation Authority (LA Metro) planning staff, working alongside engineers from the Los Angeles Department of Transportation (LADOT) seek to make improvements to the Metro G Line (Orange) busway to address a number of operational problems with the popular line. The Metro G Line is the backbone of transit in the San Fernando Valley, serving more than 22,000 pre-COVID-19 pandemic weekday boardings. Part of the problem for public transit in a chronically traffic congested place like Los Angeles is that buses typically have to compete for road space with private automobiles. As a result, buses get stuck in traffic. Light rail vehicles, when travelling on surface streets with cars, get stuck in traffic as well. The G line busway thus has a significant advantage, as it runs on its own dedicated route. Efforts to further separate the G line from nearby traffic, such as grade separated over- and under-passes or railroad-style gate arms at street crossings, will require complex planning and take considerable time and resources to implement. However, speeding up the G line with current infrastructure is possible by improving transit signal priority (TSP). TSP prioritizes a direction along a roadway by extending green time at signals so priority vehicles (in this case buses) can pass through an intersection without stopping.This report explores the current signal regime along the G line alignment, some of the history of the TSP system, and draws on case studies to develop applicable lessons to the Metro G line.