New instruments are quantitatively measuring vehicle emissions under real-world conditions. Hughes has fielded a cost-effective, real-time remote emissions sensor (RES) employing infrared technology to determine emission levels of CO, HC, and NO. Separate processors within the RES capture license plate and speed/acceleration data within the same 0.8 - second window as emissions data. Field tests have shown excellent correlation between high emitters identified by the RES and by IM240 measurements. Similar technology is being employed on miniaturized high-temperature units for vehicular on-board emissions monitoring. An on-vehicle prototype will be demonstrated this year.