Abstract: A method of constructing a modular bridge across a span (20) is disclosed. A vehicle (1) is positioned next to the span (20). The vehicle has a launching assembly (10) including an A-frame (40) which is moved from a stored position, in the launching assembly, to an upright, deployed position. A modular launching beam (110) is constructed by sequentially attaching modules (90,90') and then booming the launching beam as it is constructed out across the span (20). Once completed, the launching beam is pivoted about the A-frame (40) to lower the far bank end of the launching beam (110) onto the far bank. The A-frame (40) and, consequently, the home bank end of the launching. beam (110) are then raised, with the far bank end of the launching beam (110) remaining on the far bank. Once raised, a modular bridge (220) is suspended from the launching beam (110) and boomed out across the gap, additional modules being sequentially added.