Light rail systems are an increasingly popular means of transportation in many urban areas around the world, providing a high-capacity, low-cost and environmentally friendly way to move large numbers of people across busy cities. Synonyms for the term 'light rail' include streetcar, trolley, tram, and metro. These terms are broadly used to describe different types of rail-based mass transit systems, often with distinctive design characteristics and operating procedures. Whether running on dedicated tracks or shared with other vehicles, all light rail systems share a common goal of providing reliable, efficient and affordable transportation for passengers across urban regions.