Final answer:
Counties may not require emission inspections due to state autonomy in setting vehicle emissions standards and prioritizing local services over inspection programs. States like California have stricter standards, while emissions taxes offer an alternative to command-and-control regulations.
Step-by-step explanation:
Some counties in the United States are not required to perform emission inspections alongside state inspections due to various reasons including governance autonomy, differing state regulations, and local government focus on immediate community services. States have the authority to set their vehicle emissions standards and inspection requirements, which can lead to variability across the country. California, for instance, has more stringent standards due to its unique environmental challenges and legislative decisions. An emissions tax is another approach, differing from command-and-control regulation, which allows firms to determine the most cost-effective way to reduce emissions, creating an economic incentive for pollution control rather than mandating specific technologies or methods.