We used to do this loop:
http://www.gmap-pedometer.com/?r=5258049
From the start point (top area of map) we'd go to just before the road on the left (0.85 miles it seems). Then we'd do another 1.7 before we got back to the start point (a bus stop complete with little extra parking lane). 100-150 riders, start at 4:30 PM, about 7-8 minutes a lap, finishing about 7 PM. Crazy fast great fun.
Based on the satellite map it appears that the road doesn't go all the way through, or it goes under a lot of building stuff. In the old days we had two "underpasses" but it was open in the middle.