UPDATED 2021

Inspection and Emissions Tests Guide

By Caity Tarbert, Tests.com Contributing Writer

Automobile inspections are tests conducted on motor vehicles to determine their safety and adherence to emissions guidelines set by state governments. Requirements and specifications vary from state to state, but most states require registered vehicles to pass inspection tests at least every two years.

Types of Vehicle Inspections and How They Work

Safety inspections are the most common type of vehicle inspection in the United States. Some states require safety inspections on a yearly basis, while others do not require inspections at all. Maryland only requires safety inspections prior to sale or transfer of a vehicle. In states that do require periodic safety inspections, drivers must take their car to a mechanic or automotive dealership in order to have it examined by a qualified individual. Drivers will leave their car in the care of the professional for a period of a few hours while the inspection is performed. A preset appointment may be required by the mechanic or dealership in order to prioritize customers' needs. The cost of an inspection varies on a state-by-state basis but typically costs upwards of $15.

Emissions inspections are another type of vehicle inspection that some states require in addition to a safety inspection or on its own. Emissions inspections help to improve air quality by identifying vehicles in need of repair or alteration to lower their pollutant emissions into the environment. The Environmental Protection Agency, in an effort to reduce pollution and encourage clean air, began a mandatory emissions-inspection program for some areas of the country in 1990. Again, drivers must take their vehicle to a licensed mechanic or dealership to have the inspection performed, and an advance appointment may be required. Cost of the inspection varies, but is close to $30 in most states.

Aspects of Vehicle Inspections:

Because inspection requirements are decided by state departments of motor vehicles, there are many differing procedures depending on where you live. Pennsylvania requires drivers to complete a safety inspection on a yearly basis, so its requirements and stipulations will serve as an example. According to the Pennsylvania Department of Transportation's website, the following items must be checked in a safety inspection of a passenger car:

  • Suspension
  • Steering, including steering components and steering wheel
  • Braking systems
  • Tires and wheels
  • Lighting and electrical systems
  • Glazing
  • Mirrors
  • Windshield defrosters
  • Windshield washers
  • Windshield wipers
  • Fuel systems
  • Speedometers
  • Odometers
  • Exhaust systems
  • Horns and warning devices
  • Body
  • Chassis

Each category has specific guidelines that must be met in order for a vehicle to pass inspection.

For an emissions inspection, there are a variety of ways to test a vehicle's emissions depending on when it was manufactured. According to Maryland's Motor Vehicle Administration’s website, cars weighing less than 8,500 pounds that were manufactured in 1996 or later and are equipped with a computer-controlled engine and fuel system undergo an on-board diagnostics test. The test involves scanning the automobile's computer for emissions malfunctions. Other tests for earlier-model cars include a treadmill test or an idle test. Also, all cars undergoing an emissions test will have a gas cap leak check.

Vehicle Inspection Results

The results of a vehicle inspection are determined by a licensed mechanic and usually go on a pass/fail basis. For instance, if a car's brakes are not up to state standards, it will receive a passing grade on the inspection until repairs are made. Inspection results are available immediately after the inspection is performed in almost all cases. If the vehicle passes, many states will provide a dated windshield sticker or certificate for proof of successful and current inspection outcomes.

Preparation for Vehicle Inspections

Keeping a vehicle in good shape is a definite prerequisite to having a successful state inspection. Following manufacturer's guidelines on oil changes and other preventative maintenance may help a vehicle owner to avoid costly repairs at the time of inspection.

Furthermore, be sure to stay up-to-date on a state's requirements on periodic inspections. Some states will send reminder cards to drivers, while others require drivers to be responsible for remembering their inspections on their own.

Special Considerations:

While all states have varying requirements for inspections, there are also a range of requirements depending on the type of vehicle you drive. For instance, motorcycles have different inspection guidelines than 18-wheelers. Visit your state's Department of Transportation website for specific information.