A boom breakaway assembly for a spray boom used by a vehicle. The boom breakaway assembly includes a reciprocating system having a first position and a second position, a retention system, and a bias system. In the first position, the bias system applies a maximum effective bias rate to the reciprocating system and the retention system applies a holding force upon the spray boom to maintain the spray boom in a desired outward position. In the second position, the bias system applies a minimal effective bias rate to the reciprocating system and the retention system reduces or disengages the holding force upon the spray boom, thereby allowing the spray boom to move from the outward position to a breakaway position when the spray boom encounters an obstacle. The bias system returns the reciprocating system to the first position once the spray boom clears the obstacle.