The invention features a method and apparatus for remotely characterizing a vehicle's emissions performance. The method features the steps of: i) generating data representative of the vehicle's emissions performance with at least one microcontroller disposed within the vehicle; ii) transferring the data through an OBD, OBD-II or equivalent electrical connector to a data collector/router that includes a microprocessor and an electrically connected wireless transmitter; iii) transmitting a data packet representing the data with the wireless transmitter over an airlink to a wireless communications system and then to a host computer; and iv) analyzing the data packet with the host computer to characterize the vehicle's emissions performance.