Most states have titling and registration laws that require residents to title and register their cars in the state—and for new residents of the state to do so within some period of time, such as 30 days. Some states require titled cars to pass a comprehensive safety inspection. And some states also require cars owned by residents of certain counties to pass an emissions test/inspection designed to improve air quality in more densely populated counties.
In Texas, residents are required to title and register their vehicles with the Texas Department of Motor Vehicles (TxDMV). New residents must title and register their vehicles within 30 days of moving to the state. Texas also mandates a comprehensive safety inspection for all registered vehicles. Additionally, vehicles in certain counties must pass an emissions test as part of the state's effort to improve air quality. These counties are typically more densely populated and include areas such as Dallas-Fort Worth, Houston, Austin, and El Paso. The emissions test is part of the annual safety inspection, and vehicles must pass both to receive a valid inspection sticker, which is necessary for registration renewal.
