Method for automatically assessing performance of a driver of a current vehicle for a particular current trip, wherein updated current-trip driving data sets are repeatedly read from the vehicle, which current-trip driving data sets each comprises data from at least a predetermined set of basic driving data parameters, wherein new such current-trip driving data sets are read from the vehicle at consecutive observation time points separated by at the most a predetermined observation time period, charac-terised in that each of said current-trip driving data sets is read as an instantaneous value or as an average value read across a certain averaging time period of at the most 5 seconds of length, and in that the method comprises calculating the value of a first energy-based trip performance parameter by the steps, performed by server (150,160), of a) collecting previous-trip driving data sets, observed at a plurality of different observation time points, for a plurality of different previous trips made by a plurality of different drivers and a plurality of different vehicles, which previous-trip driving data sets each comprises parameter values for at least a certain predetermined set of qualified driving data parameters in turn comprising the said basic parameter set and in particular instantaneous vehicle energy consumption, and which parameter values are each read either as a respective instantaneous value or a respective average value read across a certain respective time period of at the most 5 seconds of length; b) classifying said previous-trip driving data sets into one of a plurality of different predetermined basic historic groups based upon a basic similarity measure, arranged to measure similarity between driving data sets based on respective numerical parameter values of the previous-trip driving data sets in question; c) for each of said current-trip driving data sets, mapping the current-trip driving data set in question to at the most one of said basic historic groups based upon a basic group conformity measure arranged to measure conformity for a current-trip driving data set to a basic historic group of previous-trip driving data sets, said group conformity measure being based upon numerical parameter values of the current-trip driving data set in question and upon a definition of the basic historic group in question; d) calculating a relative instantaneous vehicle energy consumption value for the respective previous-trip driving data sets in the basic historic group to which the current-trip driving data set in question is mapped, which relative energy consumption is relative to a total energy consumption for a respective trip during which the previous-trip driving data set in question was observed; e) calculating a value of the said first trip performance parameter based upon an average value of said calculated relative instantaneous energy consumptions; and f) storing the value of the first trip performance parameter in a database, communicating the value of the first trip performance parameter value to the server and/or presenting the value of the first trip performance parameter value to the driver. a) collecting previous-trip driving data sets, observed at a plurality of different observation time points, for a plurality of different previous trips made by a plurality of different drivers and a plurality of different vehicles, which previous-trip driving data sets each comprises parameter values for at least a certain predetermined set of qualified driving data parameters in turn comprising the said basic parameter set and in particular instantaneous vehicle energy consumption, and which parameter values are each read either as a respective instantaneous value or a respective average value read across a certain respective time period of at the most 5 seconds of length; b) classifying said previous-trip driving data sets into one of a plurality of different predetermined basic historic groups based upon a basic similarity measure, arranged to measure similarity between driving data sets based on respective numerical parameter values of the previous-trip driving data sets in question; c) for each of said current-trip driving data sets, mapping the current-trip driving data set in question to at the most one of said basic historic groups based upon a basic group conformity measure arranged to measure conformity for a current-trip driving data set to a basic historic group of previous-trip driving data sets, said group conformity measure being based upon numerical parameter values of the current-trip driving data set in question and upon a definition of the basic historic group in question; d) calculating a relative instantaneous vehicle energy consumption value for the respective previous-trip driving data sets in the basic historic group to which the current-trip driving data set in question is mapped, which relative energy consumption is relative to a total energy consumption for a respective trip during which the previous-trip driving data set in question was observed; e) calculating a value of the said first trip performance parameter based upon an average value of said calculated relative instantaneous energy consumptions; and f) storing the value of the first trip performance parameter in a database, communicating the value of the first trip performance parameter value to the server and/or presenting the value of the first trip performance parameter value to the driver.