Urban transportation systems face increasing demand as populations grow. Mass transit systems can help address congestion by providing alternatives to private vehicles. There are two main types of mass transit - road-based systems like buses and rail-based systems like trains, metros, monorails and light rail. These systems have advantages like reducing environmental impacts, fuel use, and congestion. Opportunities for mass transit include integrating different modes of transportation and raising public awareness of transit options. However, mass transit also faces challenges like high infrastructure costs and ensuring passenger safety and reliability of service.