About ST Pros — 20+ Years of Mobile Clean Air Check Testing in California's Central Valley
ST Pros has been providing mobile Clean Air Check testing to commercial fleets, semi-trucks, and RV owners throughout California's Central Valley for over 20 years. We're based in Clovis, CA — right in the center of the region we serve — and we've built our business on a straightforward principle: make it as easy as possible for fleet operators and vehicle owners in the Central Valley to complete their required CARB emissions testing without unnecessary disruption to their operation.
We come to you. That's the ST Pros model, and it has been from the beginning. Instead of asking fleet managers to schedule facility visits, pull drivers off routes, or coordinate towing for vehicles that may not be road-ready, we bring our mobile testing equipment directly to the fleet location. It's a simpler process, a more efficient use of everyone's time, and a better fit for the way commercial operations actually run.
Experience & Credentials
With more than two decades of mobile emissions testing experience in the Central Valley, the ST Pros team has seen and tested virtually every type of commercial vehicle that operates in this region. We're licensed and insured, and every Clean Air Check we perform is conducted by a qualified mobile testing professional who knows California's Clean Truck Check requirements and the commercial vehicles subject to them.
We complete and submit all inspection results efficiently, with a 24-hour turnaround on state submission so your compliance records stay current without delay.
Who We Serve
ST Pros works primarily with commercial fleet operators — fleet managers, trucking company owners, and businesses that operate multiple semi-trucks or heavy-duty vehicles in California's Central Valley. For these customers, our ability to test multiple vehicles during a single on-site visit is one of the most valuable aspects of our service: efficient, fleet-scale testing without facility visits or driver downtime.
We also serve individual semi-truck owner-operators and RV owners throughout the Central Valley who need convenient, professional mobile testing without the hassle of traveling to a testing facility. Whether you run one truck or a hundred, ST Pros is equipped to help.
Why Customers Trust ST Pros
20+ Years Experience
Two decades of mobile emissions testing experience serving California's Central Valley. We know CARB requirements and we know commercial vehicles.
Mobile — We Come to You
Our testing team comes directly to your fleet location. No facility visits, no towing, no wasted driver time getting to a test station.
Multiple Trucks in One Visit
Test your entire on-site fleet during a single scheduled visit. Efficient, streamlined, and designed for commercial operations.
Licensed & Insured
ST Pros is fully licensed and insured. Every Clean Air Check is completed by a qualified mobile testing professional.
24-Hour Turnaround
Inspections are completed and results submitted efficiently — with a 24-hour turnaround so your compliance records stay current.
Fleet Pricing Available
Special pricing when multiple vehicles are tested in a single visit. Military discounts also available for eligible customers.
Call Anytime
559-824-4291. We're available for calls and texts to answer questions, schedule appointments, and support your fleet's compliance needs.
Our Service Area
From our base in Clovis, we serve the full Central Valley within approximately a 75-mile radius — Fresno, Madera, Selma, Bakersfield, and surrounding communities. We're available for calls and texts anytime at
559-824-4291.
Questions About ST Pros? Call or Text 559-824-4291 — We're Available Anytime.