(CNN) -- A speeding vehicle struck and killed three girls Friday night, including twins, who were trick-or-treating in southern California, authorities said.
The girls, all 13, were in costume and carrying bags of candy in a residential area in Santa Ana.
They had the right of way at a crosswalk near an elementary school when a car hit them Friday night and sped off, according to the Santa Ana Police Department.
They were hit about 6:45 p.m., the Orange County Fire Authority said, according to CNN affiliate KTLA.
All the girls were declared dead at the scene, CNN affiliate KABC reported. Authorities have not identified them pending notification of next of kin.
Witnesses said the driver was speeding, and police are searching for two male suspects who fled on foot, the affiliate said. The vehicle, a Honda CRV, was found nearby.
"We do have a witness that followed the vehicle for a short period of time and eventually led us to where the vehicle is parked now," Santa Ana Police Chief Carlos Rojas told KABC.
KTLA said investigations indicated the vehicle was going at least 50 mph -- twice the listed speed limit of 25 mph.
The girls were thrown more than 100 feet, authorities said.
One of deadliest nights of the year
Halloween is one of the deadliest nights of the year because of the high number of drunken drivers and pedestrians on the road, according to the National Highway Traffic Safety Administration.
Two years ago, 48% of all crash fatalities during Halloween involved a drunken driver, compared with 31% on an average day in the same year, according to the agency's most recent data.
The deaths in California were just some of the tragic incidents that happened Friday.
In Lake Wales, Florida, in central Florida's Polk County, a 2-year-old boy was killed along U.S. Highway 27 by a bus transporting a work crew home, CNN affiliate WFLA reported.
According to a Polk County Sheriff's Office report, the boy was out with two adults and two children when one of the adults dropped his cell phone. The adult left the children in the median of the highway and told them to stay there while he went back to retrieve his phone. The other adult waited on the highway's shoulder.
The 2-year-old climbed out of his stroller and walked back to the highway, where he was struck by the bus. According to WFLA, the bus driver was unable to see the child and couldn't stop the vehicle in time.
The highway's northbound lanes were shut down for four hours.
In Greece, New York, near Rochester, two minors were hit by a car, CNN affiliate WHAM reported.
One person, a 16-year-old, was seriously injured. The other minor, a 3-year-old, was killed.
The car stopped, and police are investigating.
Injuries in Illinois, Arizona
In Winnetka, Illinois, just north of Chicago, a 3-year-old boy was struck and dragged by a car, CNN affiliate WLS reported.
The boy was trick-or-treating when he ran into the street and was hit by the car and allegedly dragged 40 feet before the driver stopped. She is cooperating with authorities, the station reported.
The boy is recovering from his injuries and is listed in good condition at a local hospital.
Five people were struck in Phoenix while out trick-or-treating as a group, according to CNN affiliate KPHO.
The trick-or-treaters -- three adults and two children -- were crossing a local street when a car hit them. One adult suffered minor injuries. The others -- a 23-year-old woman in a wheelchair, a 25-year-old man, a 10-year-old girl and a 2-year-old boy -- all were in critical condition.
The driver did stop and authorities are looking into the incident.
CNN's Holly Yan, JR Nichols and Greg Morrison contributed to this report.