Development of transportation/environmental efficacy indicators for impact assessment

摘要

Transportation/environmental indicators are quantifiable characteristics that provide information about the state of environment as affected by transportation develoment and activities. These indicators can furnish managerially significant data for environmental impact assessment of transportation infrastructure development and operation at any scale. Conceptually, a transportation system can be described by five sets of variables: system inputs, system outputs, system utilizations, system markets and system environment. Efficacy indicators are usually ratios within or between variables of any of the five sets. To assure that in decision making the multiple objectives of transportation services are included in impact assessment and evaluation, all interrelationships among five sets of variables must be considered. The transportation/environmental efficacy is reflected by a subset of these interrelationships. The subset encompasses major quantifiable dimensions of transportation/environmental efficacy that can be used for the comparative evaluation of system services. In the process of transportation planning, a single index capturing the subset of transportation/environmental efficacy dimensions is often required. Application of this index will simplify and facilitate selection of the best alternative decision with respect to environmental impacts. A methodology to develop and quantify indicators pertinent to fifteen dimensions of transportation/environment efficacy is presented. An index model called the comprehensive environmental efficacy index using fuzzy set theory and combining the importance of the selected indicators is also presented.