To many, the ingredients for New York City’s bike-share program suggested a sort of sadistic alchemy.

Start with notoriously unforgiving traffic. Add thousands of bicycles along the city’s most congested corridors. And see how perhaps the world’s least understanding drivers would cope with the new additions.

And one more thing: Many of the cyclists would be helmetless novices — or worse, tourists — careening into and out of lanes with the whimsy of a youngster pedaling through a suburb.

As of Monday, though, after more than five months and five million trips, none of the program’s riders have been killed on the bikes. About two dozen injuries, most of them minor, have been reported.