The invention relates to a modular heavy transport vehicle (1), particularly for use in ports, comprising means (2) for running along the ground designed capable of being driven by drive means (3). It is characterized in that said modular vehicle (1) comprises accepting means designed capable of engaging with complementing means to accept functional modules with which to equip it, as required, making it into a self-propelled vehicle or a trailer according to whether or not said running means (2) comprise drive means.