Page:Final Report - The Columbia River Interstate Bridge.pdf/66

 acquired this valuable property by making use of their credit and wholly without adding to the burden of general taxation.

Counts of the traffic are taken periodically and in time will afford interesting data of the traffic development. For instance, even at the present time more than ten times as many self-propelled vehicles as horse-drawn vehicles cross the bridge. It is notable also how much freight now goes by motor truck which did not go by that means when the river had to be crossed by ferry.

The number of operations per month of the lift span varies with the state of the river and the boat traffic. In an average month there are from 200 to 225 openings. The average time which traffic is delayed by each opening is from two to two and one-half minutes; many times the delay is only one and one-half minutes. The total time the lift span is open and traffic delayed is about ten hours per month, which includes night operations. The navigation, therefore. does not cause much more delay to the roadway traffic than a busy street intersection.

Parade of band and U.S. troops, crossing the Columbia river, opening the bridge to public travel.