A modular autonomous agricultural vehicle includes a drive module having a frame, a ground-engaging element rotatably coupled to the frame, a power source, and a drive motor receiving power from the power source and coupled to the ground-engaging element for rotating the ground engaging element. At least one toolbar module is detachably coupled to the frame for coupling the drive module to an agricultural implement or another modular toolbar segment. The modular toolbar preferably includes multiple toolbar modules coupled to each other in series to form the modular toolbar.