The bright yellow bike was locked to a telephone pole at the corner of Main and Tucker streets. The seat was missing. An empty Mountain Dew bottle, a coffee cup and a cigarette pack sat in its basket.

Somewhere out there are 51 other yellow bikes, part of a three-week-old program to promote bike use downtown.

When the program was launched in May, the bikes were clustered conspicuously along busy downtown streets. But today some wonder where all the bikes have gone.

The program has been more popular than expected, organizers said. More bikes will be added throughout the summer, but there are also concerns that people are taking them outside of downtown, storing them at home or stealing them.

A Herald-Leader reporter and photographer drove around downtown and surrounding neighborhoods yesterday for about four hours on a hunt for Yellow Bikes.

The trip turned up 10 bikes, four of which had flat tires or missing seats. Most of the 10 were in residential areas north of the downtown business district, although one bike was locked to a street sign in a neighborhood south of Chevy Chase. One bike with no seat and a flat rear tire had been locked near the corner of North Broadway and West Sixth Street for two weeks, a neighbor said.

Renee Jackson, executive director of the Downtown Lexington Corp. and a Yellow Bikes board member, said a volunteer looked for all the bikes a week ago. After searching most of the city, the volunteer found 42 of the original 52, the most distant one in north Lexington near New Circle Road.

Other than the serial numbers on the bikes, there's no way to track them.