The grade on the lower level approach up to the heavy teaming deck from the south would be 2½ per cent as compared with the present grade of nearly 5 per cent up to the present Rush Street bridge, and 5 per cent up to the present Dearborn Street bridge. The advantage of the double-deck bridge recommended in this plan is set forth in the statement of general requirements in the report made by the commission of engineers to the Board of Local Improvements on the proposed north-and-south boulevard connection. The engineers say: “The bridges over the river may be of either the bascule or the vertical lift type, and two single bridges may be used, one to accommodate boulevard traffic, the other for team traffic; or one double-deck bridge may be used, the upper deck to accommodate boulevard traffic, the lower deck for team traffic. In the case of two bridges, the present Rush Street bridge may be continued in service during the construction of the new boulevard bridge, and after completion of the latter may be temporarily used as a team traffic bridge. Eventually, however, Rush Street bridge will have to be replaced by a new bridge, and during the construction of the latter it will be necessary to divert the team traffic to other crossings. This will cause some inconvenience to this traffic, which is very heavy. The double-deck bridge avoids this difficulty, as it can be completed and put in service without disturbing Rush Street bridge; so that all the traffic of that bridge, both team and boulevard traffic, can be at once transferred to the new bridge when this is ready.” [Illustration: CXVIII. CHICAGO. MICHIGAN AVENUE, LOOKING TOWARDS THE SOUTH. Proposed double roadway running to a plaza at its intersection with Twelfth Street, and a suggestion for buildings to surround the place, including rearrangement of the Twelfth Street railway station. COPYRIGHT, 1909, BY COMMERCIAL CLUB OF CHICAGO]