ITS Benefits: Review of Evaluation Methods and Reported Benefits

摘要

The purpose of this report is to summarize the reported benefits of deployed211u001eintelligent transportation systems (ITS) and the evaluation methods used to 211u001equantify these ITS benefits. A better understanding of the actual or expected 211u001ebenefits of ITS will allow TxDOT to make prudent ITS deployment and operating 211u001edecisions. The authors present several evaluation frameworks that have been used 211u001eto evaluate and quantify ITS benefits. Many of these frameworks are based on the 211u001efive primary ITS goals (e.g. system efficiency/capacity, mobility, safety, 211u001eenvironmental impacts, and economic productivity) identified in the National ITS 211u001eArchitecture. The authors concluded that the existing National ITS Architecture 211u001eframework could serve as the basis for TxDOT's ITS evaluation methodology, with 211u001esome adaptation for TxDOT's statewide goals, deployment strategy, and other 211u001econsiderations. This report also provides a synthesis of the reported benefits 211u001efor the priority user services identified in TxDOT's ITS Deployment Strategy. The 211u001eauthors found that reported benefits for similar ITS user services ranged widely 211u001e(e.g., reductions in travel time ranged from 7 to 48 percent for ramp metering), 211u001epresumably due to different pre-existing traffic conditions and ITS 211u001eimplementation details. The wide range in reported ITS benefits without 211u001eaccompanying data on pre-existing conditions made it difficult for the research 211u001eteam to accuractely predict expected ITS benefits in Texas. The authors concluded 211u001ethat a careful re-examination of selected ITS evaluations may be necessary. The 211u001eauthors also recommend the development of an evaluation plan that could be used 211u001eby TxDOT and the research team to fill gaps in existing ITS benefits knowledge.