Study Overview

The Tampa Hillsborough Expressway Authority (THEA) is conducting a Project Development and Environment (PD&E) Study to evaluate the best way to add additional capacity within the existing Selmon Expressway right-of-way. The study area is from Himes Avenue to the overpass at Whiting Street, approximately 4.5 miles.

Learn more about the study from our video series:

Why Are Improvements Needed?

The South Selmon PD&E Study is exploring options to improve the expressway to reduce congestion while improving safety and better connecting communities and destinations within the Tampa Bay Region. The Purpose & Need of the study is explained below under each of the three topics.

Improve Safety

Within the PD&E Study limits, this southern section of the Selmon Expressway has numerous on and off ramps with short acceleration and deceleration lanes. This creates safety conflict points and bottlenecks where drivers are merging and weaving to get on and off the Expressway.

View Safety Concerns Map

Connect Communities

The Selmon Expressway provides a daily commuter link between downtown Tampa and several densely populated areas and regional attractors. The expressway serves as an important alternative to I-275 during road closures, hurricane evacuations, and regional travel in Tampa Bay.

View Regional Context Map

Reduce Congestion

In the last ten years, traffic on the Selmon Expressway has almost doubled. The southern section of the expressway is currently at capacity. Future traffic models and predicted 38% population growth (700,000 new residents by 2045) show that traffic will continue to grow and therefore congestion will get worse.

How many lanes are needed in the future?

When are 6 lanes needed? When are 8 lanes needed?

What Is Our Process?

The PD&E Study process includes four steps – to develop alternatives, screen alternatives, refine alternatives for additional evaluation, and finally, the selection of a Preferred Alternative. Click through each of the four steps below to see our process, a summary of the alternatives that were considered and eliminated, and how a Preferred Alternative was identified. Please note, we considered a No-Build Alternative throughout this study process for comparison purposes.

Five preliminary alternatives were developed based on the purpose and need for the project and with an understanding of the existing conditions and constraints along the corridor. The alternatives were developed to limit the need to expand out of the existing right-of-way and impact adjacent neighborhoods and CSX railroad while maintaining the same access at existing ramp locations.

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Click on the images below to see the conditions, considerations, and constraints that went into the development of the five preliminary build alternatives.

What Alternatives Were Considered?

Please use the interactive map below to explore the key features, typical section graphics, 3D illustrations, detailed birds-eye view plans, and noise wall locations for the two Preliminary Alternatives that were considered during the study and presented at the Alternatives Update Meeting.

After the Alternatives Update meeting held on September 10, 2020, we identified Alternative 6 as the Preferred Alternative and it has been further refined.

Click on one of the alternatives to activate the map.

+- Legend

3D Illustrations: Click to view 3D renderings

Potential Wall Locations:

Barrier Mounted Noise Walls on Shoulder
(14ft per the noise analysis)

Ground Mounted Noise Walls at Right-of-Way
(16-22ft per the noise analysis)

Barrier Mounted Noise Wall on Retaining Walls or bridge
(8ft per the noise analysis)

Additional commitment by THEA Sound/Safety Walls

+- Alternative 2

8 lanes (adds 2 lanes in each direction, inside and outside widening)

Linear Feet of Noise Walls
1,428 LF per noise analysis

Estimated Total Cost: $211M

Birds-eye View Plans

Typical Sections

+- Alternative 6

Interim - 6 lanes (adds 1 lane in each direction on the outside)
Ultimate (2033) - 8 lanes (adds another lane in each direction on the inside)

Linear Feet of Noise Walls
2,284 LF per noise analysis

Additional commitment by THEA Sound/Safety Walls
43,163 LF

Estimated Total Cost: $244M
Interim: $179M
Ultimate (2033): Additional $65M

Birds-eye View Plans
(Graphics depict interim)

Typical Sections

How Did We Evaluate the Alternatives?

The two build alternatives were compared with the no-build alternative using a set of evaluation criteria to understand environmental impacts, costs and engineering considerations. Also, each alternative was evaluated to ensure that it aligned with the study’s Purpose & Need developed at the beginning of the study.

What is the Preferred Alternative?

THEA chose Alternative 6 as the Preferred Alternative based on data from the study evaluation results and public input. The Preferred Alternative provides additional capacity, addresses congestion through 2033 and beyond, and is the most cost affordable in the short-term. The estimated interim cost is approximately $197 Million. The Ultimate 8-lane configuration would cost an additional $68 Million. Compared to other alternatives that were studied, the Preferred Alternative will limit the amount of construction needed on the outside of the roadway, require minimal reconstruction, and provide walls along the full length of the project on both sides of the roadway.

Explore the Preferred Alternative

Typical Sections

Birds-eye View Plans

Fly-through Animation Video

3D Illustrations

Your Feedback is Important!

The public comment period for the Public Hearing is now closed. THEA welcomes additional comments or questions about the South Selmon PD&E Study. Please send us an email or letter to the contact info below:


Communications Department
Tampa Hillsborough Expressway Authority
1104 East Twiggs Street
Suite 300
Tampa, FL 33602