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 Hawaii, residents are required to title and register their vehicles with the county in which they reside. New residents must register their vehicles within 30 days of establishing residency. Hawaii does not have a statewide vehicle safety inspection program; however, all vehicles are required to undergo an annual safety inspection. The safety inspection ensures that vehicles meet minimum safety standards. As for emissions testing, Hawaii does not currently require emissions testing for vehicles. The state's focus is primarily on safety inspections, and there are no additional requirements for vehicles owned by residents of specific counties regarding emissions. It's important for residents to check with their local county vehicle registration office for any specific requirements or procedures.