Definitions

DTC = Diagnostic Trouble Codes. Most heavy truck engines record speed when a trouble or fault code is set.  

HBR = Hard Brake Record. Usually records speed, engine RPM, engine load, percent throttle, brake switch status, cruise status and MIL (Malfunction Indicator Light) status.  

Calibration Data (generally the same for all manufacturers)  

     • Maximum vehicle and cruise set speed 

     • Engine and transmission calibration 

     • Horsepower rating 

     • Includes fault codes 

     • Trip data (not a set time, but simply usage since the last time trip data was reset 

Incident Data (manufacturer specific, one second intervals unless otherwise specified)  

1. Detroit Diesel/ Mercedes 

     o Hard brake: 1 minute before the event to 14 seconds after the event 

           o Usually a wheelspeed change of 7 miles per hour in one second 

     o Last stop: 1 minute 44 seconds before the event to 15 seconds after the event

2. Cummins 

     o Sudden deceleration: 59 seconds before the event to 15 seconds after the event 

     o Usually a wheelspeed change of 9 miles per hour in one second 

3.Caterpillar 

     o Quick stop: 44 seconds before the event to 15 seconds after the event 

     o Quick stop rate set from factory at 0 (off). Unless 2008 and engine s/n starts with SDP

     o Recommend 7 miles per hour per second if turned on 

     o Fault codes record incident data from 9.12 seconds before the event to 3.36 seconds after the event in 0.24 second intervals 

CNG = Compressed Natural Gas