In Texas, all vehicles registered are required to receive an annual inspection. The inspections include a comprehensive safety inspection and for some vehicles, an emissions test. The cost of the state inspections are determined by the county of registration and type of inspection required.
Harris County requires an emission test for gasoline-powered vehicles two through 24 years old. Vehicles newer than two or older than 24 years are still required to have a safety inspection.
For frequently asked questions, see the Two Steps One Sticker FAQS web page.