Interstate 10 / Baseline Road Traffic Interchange

Overview

The Arizona Department of Transportation (ADOT) is studying potential improvements to traffic flow and safety at the I-10/Baseline Road traffic interchange.

Due to the high traffic volume and congestion in the area, the current interchange design may no longer be adequate to meet the needs of the traveling public. The study will evaluate two design alternatives for the interchange: a Tight Diamond Interchange (TDI) and a Diverging Diamond Interchange (DDI). A previous Baseline Road interchange feasibility study completed in May 2020 by the Maricopa Association of Governments (MAG) identified these design alternatives to enhance regional travel at the interchange and are being carried forward for this study.

The study will develop and evaluate design concepts for the alternatives and identify the preferred design alternative as part of the Design Concept Report (DCR) and environmental clearance, taking into account current and future traffic volumes and existing and new surrounding development.

This project is planned in two phases. Phase I consists of determining the recommended configuration for the Baseline Road interchange. Phase II will consist of final design of the interchange and preparation of construction documents.

Project Area Map

Study Timeline

Public Scoping Meeting - May 9, 2023

Public Meeting for Design Alternatives - August 2024

Completed Study - Late 2024

Construction Funding - The project is not currently funded for construction.

Interchange Designs Being Considered

ADOT is considering three potential interchange design configurations for the I-10/Baseline Road Interchange project: a Modified Diamond Interchange (MDI), a Diverging Diamond Interchange (DDI) and a No Build Alternative - or do nothing option. These alternatives will be discussed in detail during the August 2024 public meeting.

No Build Alternative

This alternative would not make any improvements to the existing interchange or to Baseline Road. The No Build alternative would not reduce congestion along Baseline Road. The existing roadway and traffic signals would remain unaltered and there would not be any property impacts.

(No Build Alternative)

Modified Diamond Interchange (MDI)

The existing I-10/Baseline Road Interchange is a Tight Diamond Interchange, also known as a Compact Diamond Interchange. It is the most commonly used interchange type for freeway connections to local roads, and many of the existing interchanges within Maricopa County use this design.

The MDI alternative would keep the interchange and ramp configuration as they are, while adding some modifications to improve traffic operations, including adding new right turn lanes on Baseline Road at I-10 and additional lanes on the exit and entrance ramps. This alternative also includes the removal of the traffic signal at Wendler Drive and revising access to be right-in, right-out. This will improve the flow of traffic on Baseline Road. This alternative would have a smaller footprint than the DDI alternative, and would impact fewer existing properties. The MDI would also be less expensive than the DDI.

(Modified Diamond Interchange Alternative)

Diverging Diamond Interchange (DDI)

A Diverging Diamond Interchange (DDI) is a relatively new type of interchange that provides efficient traffic movements and reduces conflict points between traffic movements to improve safety. A DDI increases traffic flow by temporarily transitioning traffic to the left side of the road, allowing through-traffic and left-turning traffic to proceed through the interchange simultaneously, eliminating the need for a signalized left-turn. DDIs are particularly effective at locations that have high volumes of left-turn traffic on and off of freeway ramps and left-turn related safety challenges.

(Diverging Diamond Interchange traffic flow diagram)

Of the three alternatives, this alternative would have the largest footprint and would impact more existing properties. This alternative also includes the removal of the traffic signal at Wendler Drive and revising access to be right-in, right-out. The DDI would be more expensive than the MDI.

(Diverging-Diamond Interchange Alternative)

Public Meetings and Input

May 9, 2023 Virtual Public Meeting

Reunión Pública Virtual del 9 de Mayo de 2023 - en Español

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ADOT welcomes your questions and comments. Please contact us in any of these ways:

• By Phone: ADOT Project Information Line: 855.712.8530
• Email: [email protected]
• By Mail: ADOT Communications, 1655 W. Jackson St., MD 126F, Phoenix, AZ 85007