Is commuter life in Manhattan coming back? Taking a leap of faith that it is, members of the American Symphony Orchestra are offering a springtime bouquet of rush-hour programs at Bryant Park Fountain Terrace or 34th Street Herald Square Plaza. Beginning at five-thirty P.M., the 60-minute performances feature string quartets by Mexican masters Carlos Chávez and Silvetre Revultas (May 3 and 4, Bryant Bark), a percussion-intense tribute to Javier Diaz (May 5 and 12, Herald Square), jazz from Gershwin to Mingus (May 10 and 11, Bryant Park), early 20th-century woodwind trios (May 18, Bryant Park), and an international potpourri for horn quartet, the outdoorsiest of ensembles (May 17 and 19, Herald Square). —M.G.