Four-Quadrant Gate

Train-activated warning gates that, when lowered, fully block highway traffic from entering the highway-rail grade crossing. Gates lower across both approach and departure lanes on both sides of the grade crossing. Four Ðquadrant gate systems must conform to standards contained in the Manual on Uniform Traffic Control Devices (MUTCD) and satisfy the requirements of the Final Rule on the Use of Locomotive Horns at Highway-Rail Grade Crossings.

Source: Federal Railroad Administration.