The following new bicycle ordinances will take effect in the city of Cambridge on May 1:

* Bicycles may not be ridden on sidewalks in the Harvard Square and Central Square business districts as well as newly designated banned areas: Inman Square, Huron Village, Massachusetts Avenue from Wendell and Shepard streets to Russell Street and Cogswell, and all of Somerville Avenue.

In all other areas, a bicyclist, while riding on the sidewalk, may not ride at a speed "greater than a normal walk."

A bicyclist should give an audible warning before passing a pedestrian, far enough in advance to allow the pedestrian time to react. Pedestrians have the right of way on all sidewalks, and a bicyclist must yield to pedestrians in all traffic situations.

* In the event of a collision between a bicyclist and a pedestrian or with another bicyclist, both parties shall stop and exchange information required to complete a Cambridge Police bicycle accident report.

* A bicyclist shall not pass to the right of a bus or a minibus stopped at a bus stop.

The following bicycle ordinances are among those already in effect:

* Between dusk and dawn a bicycle is required to have a red light or reflector on the rear and a white headlight on the front, as well as side reflectors.

* Bicyclists must obey all traffic laws of the Commonwealth, including red lights, stop signs, and riding with traffic.

All violations of these laws are punishable by a fine of $20. A person who refuses to state his or her true name and address when stopped by a police officer for violating these laws is subject to arrest and a fine of $50.

For more information, call the city's Bicycle Program at 349-4604.