California Department of Transportation

Project Development Workflow Tasks (PDWT)

Part 3 - Identify Project Need and Project Initiation Document

II. Project Initiation Document

B. Develop Initial Alternatives (150.10) - Develop Concept Alternatives (WBS 150.10.15)

P45. Request Delay Index

A Delay Index (DI) is a benefit/cost ratio analysis (calculation) of a proposed improvement. The benefit is the direct result of reduction in traffic delay. A Delay Index calculation is required for traffic operational improvement projects (Category 310 projects or "HB4" projects). Examples of operational improvement projects include: auxiliary lanes, new lanes, HOV lanes, passing or climbing lanes, truck lanes, turnouts, roundabouts, signals and channelization at intersections, ramp metering, interchange modifications, acceleration and deceleration lanes, curve corrections, and roadway widening in some cases. These are projects that will increase the Level of Service, service flow or traffic travel speed. Operational improvement projects can be considered for programming based on the DI alone when the DI is at least 100. Because projects with a DI less than 100 lack sufficient justifications based on travel savings alone, additional means for justification should be developed.

The project engineer obtains and requests a DI calculation from the District Traffic Operations Branch. The project engineer must include with the request: project length before and after proposed improvement, travel speed before and after proposed improvement, present AADT and future design year AADT, and the estimated project construction cost.

Operational Improvement projects require justification based on a Priority Index Number (PIN). A PIN is based on both a Safety Index and a Delay Index. Project engineers must obtain SI and DI calculations from the appropriate offices and should not perform their own calculations.

Projects costing $5 million or more are candidates for “A+B” and Incentive/Disincentive (I/D) contracts. The “D” portion of the contract and the I/D portions of the contract are based on a road user cost (RUC). The DI calculation contains the daily user cost; thus the project engineer can use the DI calculation to evaluate the project for A+B and I/D contracts. The RUC analysis for purpose of A+B or I/D projects shall be requested and obtained from the district Traffic Operations Branch.


Guidelines for Use of A+B Bidding Provisions

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This page last updated October 20, 2010