An electric or hybrid traction vehicle, comprising: - a passenger compartment; - an air conditioning system for conditioning said passenger compartment by means of at least one air flow; - at least one electrical and/or electronic component which tends to heat up during normal operating conditions; the air conditioning system comprising: - a waste heat dissipation and recovery system comprising: a) a first circuit, in which a heat transfer fluid flows, in use; b) a first heat exchanger for removing heat from said electrical and/or electronic component; and c) at least one second heat exchanger for transferring the heat removed by said first heat exchanger to said air flow; - an aeraulic duct conveying said air flow towards said passenger compartment; - a refrigerating assembly comprising a third heat exchanger or evaporator, arranged along said aeraulic duct and configured to remove heat from said air flow; said second heat exchanger being arranged along said aeraulic duct in series with, and downstream of, said third heat exchanger or evaporator; the waste heat dissipation and recovery system further comprising: - a further heat exchanger for transferring, to a fluid, at least a part of the heat which has been removed by said first heat exchanger; - moving means for forcedly making said fluid circulate through said further exchanger; - a bypass pipe arranged in parallel to said second exchanger; and - a three-way regulating valve controlled so as to adjust the heat exchanged by said second exchanger by splitting the flow rate of said heat transfer fluid between said second exchanger and said bypass pipe; characterized in that said further exchanger is arranged in series with, and downstream of, said second exchanger and said bypass pipe and upstream of said first exchanger. - a passenger compartment; - an air conditioning system for conditioning said passenger compartment by means of at least one air flow; - at least one electrical and/or electronic component which tends to heat up during normal operating conditions; - a waste heat dissipation and recovery system comprising: a) a first circuit, in which a heat transfer fluid flows, in use; b) a first heat exchanger for removing heat from said electrical and/or electronic component; and c) at least one second heat exchanger for transferring the heat removed by said first heat exchanger to said air flow; a) a first circuit, in which a heat transfer fluid flows, in use; b) a first heat exchanger for removing heat from said electrical and/or electronic component; and c) at least one second heat exchanger for transferring the heat removed by said first heat exchanger to said air flow; - an aeraulic duct conveying said air flow towards said passenger compartment; - a refrigerating assembly comprising a third heat exchanger or evaporator, arranged along said aeraulic duct and configured to remove heat from said air flow; said second heat exchanger being arranged along said aeraulic duct in series with, and downstream of, said third heat exchanger or evaporator; the waste heat dissipation and recovery system further comprising: - a further heat exchanger for transferring, to a fluid, at least a part of the heat which has been removed by said first heat exchanger; - moving means for forcedly making said fluid circulate through said further exchanger; - a bypass pipe arranged in parallel to said second exchanger; and - a three-way regulating valve controlled so as to adjust the heat exchanged by said second exchanger by splitting the flow rate of said heat transfer fluid between said second exchanger and said bypass pipe; - a further heat exchanger for transferring, to a fluid, at least a part of the heat which has been removed by said first heat exchanger; - moving means for forcedly making said fluid circulate through said further exchanger; - a bypass pipe arranged in parallel to said second exchanger; and - a three-way regulating valve controlled so as to adjust the heat exchanged by said second exchanger by splitting the flow rate of said heat transfer fluid between said second exchanger and said bypass pipe; characterized in that said further exchanger is arranged in series with, and downstream of, said second exchanger and said bypass pipe and upstream of said first exchanger.