In 2001, the city's Transportation Department tested a light blue bike lane in Downtown Brooklyn and found that in terms of making the lane sufficiently visible to cyclists and drivers alike, it did the trick. But at the urging of the Federal Highway Administration, the department has forgone blue for the Brooklyn Heights bike lane and decided to experiment with green, echoing a growing national movement to make green the official bike lane color.

Other streets are getting paint jobs, too. Last week, in an experiment in making bus lanes more visible, the city laid down coats of terra-cotta-colored paint on bus lanes along part East 57th Street, and it will soon do the same for lanes on Fordham Road in the Bronx.

After the Second Avenue subway finally rolls, it also may eventually bring a new color. The Web site of the Metropolitan Transportation Authority shows a T - the letter tentatively chosen to denote the new line - sitting in a circle of turquoise. (According to Jeremy Soffin, a spokesman, the agency has not yet chosen a permanent color for the circle.)

The choice is of special interest to Lynne Lambert, whose New York City Subway Line is an official licensed maker of subway-themed merchandise. Whatever color is chosen will make its way onto T-shirts, hats and other items Ms. Lambert produces, and she said she would be happy to see the choice on the transportation authority's Web site become permanent.