Method for determining characteristic parameters of the operation of a vehicle, said vehicle comprising a powerplant provided with at least one motor (21, 22) and a mechanical power transmission means, control means (24, 25, 26) for controlling the movements of said vehicle, a plurality of sensors, at least one calculation means, at least one memory and at least one display means, during which method - various pieces of information relating to the surroundings of said vehicle and/or to the state and the operation of said vehicle and said powerplant, and/or to the state of said control means (24, 25, 26), and/or to the position and to the movements of said vehicle relative to the surroundings thereof are measured, - an available power margin of each motor (21, 22) of said powerplant with respect to a minimum guaranteed power is determined, said available power margin being characteristic of a state of ageing of each motor (21, 22) of said powerplant, - a maximum available power is determined at each motor (21, 22) of said powerplant, taking into account said available power margin, - at least one characteristic power of each motor (21, 22) of said powerplant that corresponds to the implementation of a predetermined manoeuvre X of said vehicle is determined, - at least one first value P i _lim that corresponds to said maximum available power of each motor (21, 22) of said powerplant and to a limit value that a parameter P i may not exceed is determined, P i being a parameter relating to the state or the operation of said vehicle, or to the state or the operation of said powerplant, or to the state of said control means (24, 25, 26), or to the position or to the movements of said vehicle relative to the surroundings thereof, - at least one second value P i _X that corresponds to a characteristic power of each motor (21, 22) for implementing a predetermined manoeuvre X of said vehicle and to which said parameter P i must be equal in order for said vehicle to be able to carry out said predetermined manoeuvre X is determined, and - each first value P i _lim and each second value P i _X are displayed simultaneously on the same graphical representation in order to clearly show the relative position of a first value P i _lim with respect to each second value P i _X for each parameter P i. - various pieces of information relating to the surroundings of said vehicle and/or to the state and the operation of said vehicle and said powerplant, and/or to the state of said control means (24, 25, 26), and/or to the position and to the movements of said vehicle relative to the surroundings thereof are measured, - an available power margin of each motor (21, 22) of said powerplant with respect to a minimum guaranteed power is determined, said available power margin being characteristic of a state of ageing of each motor (21, 22) of said powerplant, - a maximum available power is determined at each motor (21, 22) of said powerplant, taking into account said available power margin, - at least one characteristic power of each motor (21, 22) of said powerplant that corresponds to the implementation of a predetermined manoeuvre X of said vehicle is determined, - at least one first value P i _lim that corresponds to said maximum available power of each motor (21, 22) of said powerplant and to a limit value that a parameter P i may not exceed is determined, P i being a parameter relating to the state or the operation of said vehicle, or to the state or the operation of said powerplant, or to the state of said control means (24, 25, 26), or to the position or to the movements of said vehicle relative to the surroundings thereof, - at least one second value P i _X that corresponds to a characteristic power of each motor (21, 22) for implementing a predetermined manoeuvre X of said vehicle and to which said parameter P i must be equal in order for said vehicle to be able to carry out said predetermined manoeuvre X is determined, and - each first value P i _lim and each second value P i _X are displayed simultaneously on the same graphical representation in order to clearly show the relative position of a first value P i _lim with respect to each second value P i _X for each parameter P i.