摘要: |
The purpose of this report is to summarize the reported benefits of deployed intelligent transportation systems (ITS) and the evaluation methods used to quantify these ITS benefits. A better understanding of the actual or expected benefits of ITS will allow the Texas Department of Transportation (TxDOT) to make prudent ITS deployment and operating decisions. The authors present several evaluation frameworks that have been used to evaluate and quantify ITS benefits. Many of these frameworks are based on the five primary ITS goals (e.g., system efficiency/capacity, mobility, safety, environmental impacts, and economic productivity) identified in the National ITS Architecture. The authors concluded that the existing National ITS Architecture framework could serve as the basis for TxDOT's ITS evaluation methodology, with some adaptation for TxDOT's statewide goals, deployment strategy, and other considerations. This report also provides a synthesis of the reported benefits for the priority user services identified in TxDOT's ITS Deployment Strategy. The authors found that reported benefits for similar ITS user services ranged widely (e.g., reductions in travel time ranged from 7 to 48% for ramp metering), presumably due to different pre-existing traffic conditions and ITS implementation details. The wide range in reported ITS benefits without accompanying data on pre-existing conditions made it difficult for the research team to accurately predict expected ITS benefits in Texas. The authors concluded that a careful re-examination of selected ITS evaluations may be necessary. The authors also recommend the development of an evaluation plan that could be used by TxDOT and the research team to fill gaps in existing ITS benefits knowledge. |