Be sure your vehicle is properly warmed to operating temperature before you’re tested.  “Cold” vehicles emit higher levels of pollution than those at operating temperature. In general, 10-15 minutes of drive time will ensure proper warm-up.

Air Care Colorado Consumer Information

Wait Time Note: Please keep in mind that the wait times include an average test time of 20 minutes, so if the wait time for a station says "30 minutes," the actual wait prior to the test is about 10 minutes.  The wait times are updated approximately every 15 minutes.