An articulated vehicle includes a rear frame and a front frame linked by an articulation associated with the device for removably locking controlled by a pendular member mounted oscillating on the front frame between a median position for unlocking the articulation and a spaced apart position for locking the articulation, at least when the vehicle is stopped. The vehicle comprises elements for controlling the unlocking of the articulation, at least during start-up, including an auxiliary platform integral in rotation with the rear frame and comprising, at least, two footrests arranged at substantially the same level relative to the ground, on either side of the articulation axis and constituting each, on the side towards which the front frame is inclined, a support for the front frame to be set upright by the vehicle driver, the pendular member returning to its median position for unlocking the articulation.