Tool for environmental performance assessment of city bus transit operations: case studies

The purpose of this article was to present a tool for the assessment of the environmental performance of bus transit operators. The research method was the qualitative modeling. Environmental performance is the result of the environmental management practices adopted by an organization. Environmental performance was hierarchically structured in criteria and indicators. The assessment process produces an overall dimensionless index, a pure number without an associated physical dimension, originated from expert judgments and according to a composition rule. Experts attribute a degree of compliance to expected performance, ranging between 0 and 100 % (respectively the worst and the best), to the situation of environmental categorical indicators. Five criteria, apprehended by 32 indicators and prioritized by analytic hierarchy process, were used in the tool: Atmosphere (39 %), regarding impacts of the bus operation in air quality; effluents (6 %), regarding impacts caused by liquid waste; solid waste (8 %), regarding the generation of solids; land use (18 %), regarding how the operation uses the land; and natural resources (29 %), regarding how efficient the operation is in using natural resources. The tool was tested in six bus transit operations of a Latin America city of about 1,500,000 inhabitants. Indicators were assessed by scales fulfilled by managers of the operations. The overall dimensionless results for the six operators were: 58.96; 53.24; 50.97; 54.07; 47.01; and 37.69 % of the maximum possible performance. This numbers represent the degree of global satisfaction of the experts with the environmental results obtained by the operators. For all six operators, the more problematic criterion was Atmosphere. An improvement strategy should focus on it, implementing corrective actions monitored by the indicators of the criteria.