Abstract: The truck operation monitoring system is mounted in a truck cab and comprises: a plurality of sensors each positioned to sense an operating parameter of the truck; at least one primary instrumentation module mounted in the truck cab and including a data processing apparatus, means for coupling the sensors to the processing apparatus, memory means coupled to the data processing apparatus for storing data picked up from the sensors, and display means coupled to the data processing apparatus; means for manually calling up information on the display means and/or for inputting information into the processing apparatus; and means for communicating the memory means with a larger data processing apparatus. The system can also include a secondary instrumentation module mounted in the truck cab and having second display means for displaying truck operating parameters. The means for calling up or inputting information can be realized by a keyboard on the secondary instrumentation module.