y vehicle does not emit smoke and there isn't a spot of rust, why does it need to be tested?

Many motorists believe that a vehicle which does not emit smoke and has an immaculate paint job is a well-maintained vehicle. Outward appearance of a vehicle is not an accurate indication of how well the vehicles engine has been or is maintained. The pollutants detected by the E-Check test are odorless, nearly colorless and therefore, undetectable by the naked eye. If a vehicle does not pass the E-Check test, the vehicle is not operating "cleanly" with regard to the harmful emissions. If all emissions repairs are made to a vehicle to bring that vehicle into compliance, the motorist generally experiences an improvement in gas mileage. Proper emissions repairs also lengthen vehicle life. Regardless of age or mileage, vehicles that are maintained in accordance with manufacturer's recommendations have a better chance of passing the emissions test. Passing the E-Check test indicates that your vehicles emission control system is operating well, polluting less, and consuming less gas.