Taxi fleet owners sued New York City Mayor Michael Bloomberg and the city Wednesday in an effort to block new rules that allow livery cabdrivers to pick up passengers who hail them on the street.

The Metropolitan Taxicab Board of Trade alleges that the city and the Taxi and Limousine Commission, which is expected to approve the rules for so-called borough taxis on Thursday, are depriving owners of the city's 13,000 yellow-cab medallions of their "exclusive right" to accept street hails.

The...