Sustainability Indicators of Surface Public Transportation

Historically, roads and transportation have been critical and essential factors in the development and prosperity of cities and societies. The well-being of cities and their expansion were measured by the road networks that linked them to the rest of the world, especially the land roads, which were the biggest challenges for communities. With time, the transportation sector has become an integral part of human life. However, this contribution to the development of cities has come to collide with the challenges arising from the means of transportation, which include large-scale environmental, economic, and social impacts on the communities benefiting from them. Therefore, it has become necessary to make transportation, especially public transportation, sustainable to address environmental challenges such as climate change. To achieve this, more than two thousand research papers published between 2002 and 2022 and retrieved from scientific databases using specific and connected keywords were preliminarily investigated based on the year and number of citations. It was necessary to identify the important sustainability indicators for each sector and study them closely in a detailed manner. We concluded that the sustainability of public transportation is directly affected by environmental, economic, technical, and social factors which can be expressed as follows: 1—emissions, pollution, and the consumption of energy resources as environmental indicators related to sustainability; 2—travel time, cost, travel distance, and operation cost as economic indicators; 3—social demographics, accessibility, and travel behaviours and time as social indicators; and 4—traffic flow, speed, and availability of infrastructures as technical indicators that affect transport sustainability.