Having run simulations and measured the effects of intervention strategies, it becomes possible to examine costs and benefits of implementing ICM. In AMS Phase 1, the Connected Corridors team conducted an initial estimation of costs and benefits.
Constraints
The nature of AMS Phase 1 imposed several constraints on assessing costs and benefits:
- The limited size of the Phase 1 test area meant only a subset of the corridor was simulated.
- The simulation results in this initial phase were, consequently, tentative.
- Useful estimates were not yet available for many of the costs related to either the decision support system or operations and maintenance.
- Discussions with stakeholders about cost assumptions were ongoing.
Given these limitations, the purpose of the cost/benefit assessment in AMS Phase 1 was to test and evaluate the methodology of the analysis, rather than to assess the value of ICM. The Phase 1 cost/benefit analysis should thus be seen as an example illustrating the methodology to be carried forward and refined in Phase 2, where a fair and complete comparison between benefits and costs can be undertaken.
Costs
To understand the costs of implementing ICM strategies, the team assessed the status of existing infrastructure, including freeway, arterial, and support infrastructure. Two risk areas for the I-210 pilot were identified:
- Real-time situational awareness on the arterials
- Ability to disseminate travel information to influence driver route choices
As a result, arterial sensors and changeable message signs (CMS) received the focus of attention in the study. Additional infrastructure requirements, including control functions, communications connectivity, and decision support, will continue to be identified as part of the ongoing systems engineering process.
Benefits
The team estimated benefits by calculating cost savings from:
- Reduction in delay
- Reductions in vehicle operating costs
- Reductions in emissions
- Improved travel time reliability
The benefit assessment was carried out with the help of the corridor version of Cal-B/C, a PC-based spreadsheet model developed by Caltrans’ Economic Analysis Branch and System Metrics Group. Cal-B/C has been widely used to evaluate the life cycle benefit/cost of proposed state highway and public transit projects.
The performance metrics calculated from the simulation results, such as vehicle miles traveled (VMT) and vehicle hours traveled (VHT), are used as input to Cal-B/C. Relative benefits with and without the intervention were calculated for the simulated incident.
For more information on the AMS Phase 1 cost/benefit evaluation, see the AMS Phase 1 Report.