Pennsylvania requires an annual state inspection and emissions testing to ensure that vehicles on the road meet certain safety and environmental standards. The purpose of the inspection is to identify any mechanical or safety issues that may make a vehicle unsafe to operate or cause it to pollute the air excessively.

The inspection helps to keep the roads safe by identifying issues such as faulty brakes, tires, lights, and steering systems. These issues, if left unchecked, could cause accidents and put other drivers and pedestrians at risk.

In addition to the safety inspection, Pennsylvania requires an emissions test to ensure that vehicles are not emitting excessive amounts of pollutants into the air. This helps to reduce air pollution and improve air quality for residents of the state.

During a state inspection in Pennsylvania, a certified mechanic will inspect the following components of a vehicle:

1. Brakes: The brake system is checked for any leaks, wear, or damage to the pads, rotors, and calipers.

2. Steering and Suspension: The steering and suspension system is checked for any wear or damage to the steering column, tie rods, ball joints, and shocks.

3. Lights: All lights, including headlights, taillights, brake lights, and turn signals, are checked to ensure they are functioning properly.

4. Tires and Wheels: The tires are checked for proper tread depth, any cuts, bubbles or other damage, and the wheels are checked for any damage or cracks.

5. Exhaust System: The exhaust system is checked for leaks, proper operation of the catalytic converter, and to ensure that it meets the state's emissions standards.

6. Fuel System: The fuel system is checked for leaks, and to ensure that the gas cap is functioning properly.

7. Body: The body of the vehicle is checked for rust and any other damage that may compromise the structural integrity of the vehicle.

Overall, the state inspection in Pennsylvania is designed to identify any mechanical or safety issues that could make a vehicle unsafe to operate.