This bridge, a public works project during the Great Depression, was designed to ease traffic flow on Michigan Avenue and in the Loop.

The delay cost estimated to be one cent per car per minute (60 cents per hour for the value of time or the value of fuel saved) resulted in a savings in vehicle operation of $584,000 per annum; that amount capitalized at 5% would indicate that $23,360,000 could properly be spent to eliminate this delay, in the eyes of the decision makers at the time of the construction.

The operating pinion, with a pitch diameter of 40 inches (100 cm), is mounted on a shaft of the gear train.

The center lock in addition to holding the leaves together in their closed position, also transmits live load shear from one leaf to the other.

The four locks of a leaf are connected by shafting, and operation by means of two 15-horsepower motors set either side of the centerline of the bridge" (April 22, 1937).