Given the current state of transportation funding in the United States, in many jurisdictions the only capital projects under consideration are those that apply toll charges to offset part or much of the capital or operating costs of potential new roads. Such projects are best evaluated with robust analysis findings given the extra stakeholder attention that accrues to tolled projects and the financial stakes involved. While regional demand models can treat many types of tolled facilities in a general sense they lack the temporal (and sometimes the network) fidelity necessary for thorough managed lane analysis. The Express Lane Time-of-Day (“ELToD”) model was developed to add a robust and rapid-response managed lane analysis capability to studies where the demand estimation can be carried out in a regional model.
ELToD estimates traffic, dynamic toll rates, and revenues in one-hour intervals across an entire day for a subarea network extracted from the regional model. It is sensitive to managed lane travel time savings, the toll charged, and the unreliability of travel time in the alternate general-purpose-lane path choices. ELToD has been used to quickly test different network configurations for preliminary design purposes, to compare and evaluate potential managed lane alternatives in planning studies, and to inform further analysis in investment-grade studies. This paper will examine the current structure of the ELToD tool (how it estimates unreliability, tolls, and network performance) in light of its recent validation against observed data in a base year. Validation criteria included managed lane volumes, managed lane toll rates, and managed lane share of overall traffic. The paper will discuss some of the validation challenges and solutions, and will also remark potential future directions for further tool enhancement.