A DUI checkpoint in New Canaan last Friday night resulted in three arrests, four marijuana citations and about 20 infractions or verbal warnings issued for minor violations, according to police.

The checkpoint was staged under the Merritt Parkway overpass on Old Stamford Road, near the Talmadge Hill train station, from about 7 p.m. Friday to 3 a.m. Saturday.

At about 8:30 p.m., two Norwalk men were found with heroin, Adderall and drug paraphernalia, police said. James Murphy, 25, of Orlando Road, and Perry V. Landsman, 24, of Nursery Street, were each charged with possession of narcotics and possession of drug paraphernalia. Murphy, the driver, also was charged with possession of a controlled substance.

The third arrest took place at 2 a.m. after police noticed signs of intoxication in a woman driving a 2013 BMW with a flat tire, according to the report. Kathleen F. Isaacs, 50, of Tobacco Road, Weston, was charged with operating under the influence of alcohol and/or drugs after she failed the field sobriety tests. Police said she told them she did not remember what caused the flat tire, but she said she "possibly" hit something on Jelliff Mill Road.

Murphy and Landsman are scheduled to appear in court Dec. 30 and Isaacs on Jan. 8.

Four other people were issued infractions for marijuana violations, according to police.

Ryan C. Kupferschmid, 18, of Capalbo Place, Greenwich, was issued infractions for possession of less than half an ounce of marijuana and possession of drug paraphernalia. A passenger in another car also received an infraction for possession of less than half an ounce of marijuana. She was Krystal L. Gonzalez, 21, of Hope Street, Stamford.

Two other Stamford residents, a driver and a passenger in the same car, were issued infractions for both possession of drug paraphernalia and possession of less than half an ounce of marijuana. They were James A. Roza, 21, of Interlaken Road, and Noelle M. DePonte, 18, of Rockrimmon Drive.