The timeline represents the required steps in the development of a roadway or roadway improvement. In addition to establishing a funding source, there is a series of required planning and environmental studies before a roadway is constructed.

Voter Approval
In November 2004, Maricopa County voters approved a 20-year extension of a half-cent sales tax through 2025, to fund a comprehensive package of transportation improvements as part of a Regional Transportation Plan. Funding for the plan, which includes $9 billion in regional freeway improvements in Maricopa County, became effective January 1, 2006.

Planning
Freeway planning to determine potential future corridors and freeway improvements is conducted well in advance of design and construction. Area population growth, future land use, jurisdictional responsibilities and other factors are used to determine the need, feasibility and general location of future freeway improvements.

Study
The study stage establishes the location (alignment) and basic characteristics (number of lanes, type of traffic interchange, etc.) of a roadway. Accompanying this are environmental studies (noise and economic impacts), identification and evaluation of alternatives, general cost estimates, coordination with public and private partners and the determination of feasibility to move to the design phase.

Design
The design of a roadway involves several stages of detailed engineering and technical review and interim levels of approval. Project information is shared and discussed with the public at project milestones and public input is considered in the evaluation of design alternatives, as well as during final design. The final design of the roadway is represented in plans and specifications that construction contractors use to prepare construction bids.

Construction
Road construction is based on detailed plans and specifications provided to the contractor following the approved design. ADOT continually looks for ways to improve the construction process for maximum efficiency and minimal community impact. Once built, a roadway may be improved over time as a result of future studies.

Our Valley Freeway System is part of the 2004 voter-approved Regional Transportation Plan. We are working hard with our transit partners to implement the voters’ vision and are committed to quality, safety, open communication with our neighbors, and minimal inconvenience to the traveling public.