PrePass sites that are equipped with transponder technology (RFID readers) will signal your transponder with the appropriate decision (green or red light). In this case, the PrePass app will alert you that you are approaching a weigh station and will notify you to “Follow in-cab transponder.” At weigh stations not equipped with transponder technology and offering mobile app bypassing only, you will not be signaled by your transponder, and the PrePass app will provide the appropriate decision on your device screen.