Some advantages of a Michigan Street alignment vs. an Illinois Street alignment of the proposed bridge.
Any potential bridge at the Illinois Street location would be adding to the complexity and confusion of the intersections on either side of the bridge.
On the south side, there is already a confusing and busy intersection where Cargo Way meets 3rd Street and Amador. Trucks trying to get over the Illinois Street bridge will of necessity impact stop light timing at that intersection. Allowing truck traffic only from Amador and Cargo Way doesn't help very much since a second light would still be needed to accommodate south flowing traffic off of the bridge onto Cargo Way across traffic destined for 3rd Street.
On the north side, truck traffic ultimately destined for Cesar Chavez and Highways 280 and 101 must make a left turn onto a very short block of Cesar Chavez, probably only good for 1.5 full size trucks, creating a 2 light bottleneck (Illinois/Cesar Chavez and 3rd/Cesar Chavez). Useful for getting trucks off of 3rd perhaps, but a step backward in terms of pollution caused by idling trucks.
A bridge at Michigan St. would alleviate both problems above.
Truck traffic from the southern waterfront would have less cluttered direct access to the bridge, both from Amador and Cargo Way since both of these intersections are now another block away from the much larger and busier convergence of Cargo Way, Amador and 3rd Street.
On the north side, trucks destined for 101/280 would have an extra block to line up at the 3rd Street./Cesar Chavez light. Since Michigan Street. ends at Cesar Chavez, that left turn would have more efficient light timing (or perhaps just a stop sign) and thus, less waiting of idling diesel trucks.
It's been suggested that the grading problem from bridge height to road height also exists at the Michigan Street location, but there is already a rail grading adjustment to get from the Illinois Street rail spur up to the loading dock height of the channel side of Shed "A". Some of the grade adjustment could also be done on the bridge itself. It appears from my untrained eye that there may exist enough space to tie the rail from the bridge onto this spur with the requisite turning radius. Even if there weren't, it wouldn't require much adjustment of existing rail to accommodate this radius. Grading much of the port yard around this bridge approach would maintain truck access to either side, preventing the road from acting as a barrier to both halves of the port property, although this access would probably be a bit more restricted now that it would be crossing an active road.
Michael Prichard - OQO, Inc. - Head of Product Design - (415) 920-9090 x201