The Tlaquepaque Underpass – The “Real Story”

By Steve Segner

Residents deserve an accurate understanding of why the underpass was built, who controls the crosswalk, and how decisions are made.

Why the Underpass Was Built

The SR-179 approach into the “Y” has long been one of the most constrained traffic corridors in the region. Thousands of visitors, employees, and residents cross a high-traffic state highway between the two sides of Tlaquepaque. The at-grade crosswalk — while essential to the property’s operation — has been a significant point of conflict for pedestrian safety and traffic flow.

The City of Sedona and ADOT jointly developed the underpass to address three long-standing issues:

1    Safety: Separating pedestrians from traffic reduces risk in a high-volume corridor.

2    Traffic Flow: A few pedestrians crossing at peak times can halt northbound movement.

3    Connectivity: The new ADA-compliant shared-use path offers continuous access under SR-179 and along Oak Creek.

This project became part of the city’s master plan to address traffic and infrastructure issues, referred to as “Sedona in Motion” (SIM), a 10-year, expensive, but necessary set of initiatives to make Sedona a better place to live, visit, and enjoy.

Project Cost

The underpass was approved in April 2023 at $3.46 million. After normal adjustments and change orders, the final cost was approximately $3.50 million, with construction completed in October 2024.

Not a Silver Bullet — Staff Told Us That From Day One

City staff consistently stated that closing the crosswalk would not “fix” congestion at the “Y”. A small number of residents — and even some council members — pushed the idea that crosswalk removal would dramatically speed traffic. But engineering analysis showed the opposite: while the crosswalk contributes to delay, it is only one of many small factors affecting the corridor.

In fact, the crosswalk can help by spacing vehicles as they approach the Y, thereby increasing throughput during compression.

Sedona’s traffic issues stem from layered pinch points, visitor surges, time-of-day patterns, and limited roadway capacity. Every improvement we make is incremental, not transformational. The underpass is an important tool — but it was never presented as a cure-all.

Who Controls the Crosswalk? (Hint: Not the City)

Another misconception is that the City can remove the crosswalk. It cannot.

SR-179 is a state highway. The crosswalk is under ADOT jurisdiction, and any change requires their approval.

How Temporary Closures Actually Work

To keep traffic from collapsing into gridlock, the City uses a data-driven system monitoring real-time travel times on:

• SR-179 northbound from Bell Rock
• SR-89A northbound down Cook’s Hill
• SR-89A southbound from Trout Farm

When travel time on SR-179 reaches:

• 14 minutes added to normal drive times on peak days
• 18 minutes added to normal drive times on off-peak days

…the at-grade ST179 crosswalk, which connects both sides of Tlaquepaque and the Center for New Age, is temporarily restricted to maintain flow. When congestion eases, it reopens. These thresholds are continuously refined to balance two priorities:

1    Keeping northbound traffic moving

2    Minimizing impacts on Tlaquepaque businesses and visitors

This is not guesswork — it is data and engineering.

A Practical, Evidence-Based Improvement — Not a Magic Wand

The underpass enhances safety, improves reliability, and reduces conflict. It was never intended to “solve” traffic, because no single project can. Sedona’s transportation system is strained by periodic, extraordinary visitor demand and its constrained geography. Only a long-term series of incremental measures can improve the situation.

What this project demonstrates is simple:

We are better off listening to trained engineers and city staff than to those who believed — and continue to insist — that a $3 million infrastructure project would magically “fix” traffic at the Y. It didn’t, and it won’t. That was never its purpose.

The City made the right decision by weighing safety, mobility, jurisdiction, business needs, and long-term planning — not wishful thinking