Two men were arrested Wednesday night in connection with the crash: Khusen Akhmedov, 23, of Lancaster, and Ahmen Holloman, 30, of the 7000 block of Souder Street in the Castor Gardens section of Northeast Philadelphia. They were charged with homicide by vehicle, third-degree murder, involuntary manslaughter, and related offenses.
Akhmedov was identified as the driver of the Audi.
Police said a witness had observed the Audi drag-racing with a 1994 Honda along the southbound Boulevard.
"It is one of the most unsafe roads in the country," said Dan Hessel, a lawyer who is an authority on the dangers of Roosevelt Boulevard. "And it has that reputation as the most unsafe road in the city because of the interplay between the residential areas, commercial areas, and bus stops."
In the last seven years, the highway has been the focus of detailed studies and improvements. A task force was created to reduce fatalities and injuries, its members including PennDot, the Delaware Valley Regional Planning Commission, the Federal Highway Administration, SEPTA, and the city Streets Department, Police Department, Parking Authority and Planning Commission.
Their work, among other initiatives, included a $2.8 million improvement project completed this year. That work added signals to five so-called mid-block crosswalks and installed 12 pull-off areas in the median. Those pull-offs created spaces where police could provide visual presence and conduct enforcement.
Banks, 27, and her children were killed as they crossed the Boulevard near North Second Street, an odd area of the highway for pedestrians.
Highly visible crossing areas stand well to the east and west. But Second Street, coming in from the north, abuts directly against the Boulevard. The only clue that pedestrians may cross there lies beyond, in the strips of walkway on the Boulevard medians.
Technically, the area is not a mid-block crosswalk, because Second Street runs on both sides of the Boulevard. At the same time, it isn't an intersection, because Second Street does not run through the highway.
The area does not have pedestrian signs or a marked crosswalk. There's no traffic light. But it is legal for walkers to cross at that location, according to Gene Blaum, PennDot spokesman.
That spot has no significant history of accidents, but "we will certainly take a look at it after this tragic crash," he said.
For Banks, a routine walk turned deadly about 10 p.m. Tuesday.
The driver of the Audi stayed at the scene after the crash, and was taken to Police Headquarters to be tested for drugs or alcohol.
At the crash scene Tuesday, a police supervisor stood beside an overturned stroller, the street littered with debris from the Audi's smashed front end.
Killed with Banks were her 9-month-old son, Saa'mir Williams; her 23-month-old son, Saa'sean Williams; and her 4-year-old son, Saa'deem Griffin.
Banks and Saa'sean were pronounced dead at the scene. Saa'mir died at Einstein Medical Center. Saa'deem was taken to St. Christopher's Hospital for Children, where he died at 4:45 a.m. Wednesday.
The lone survivor was Banks' oldest son, 5-year-old Saa'yon Griffin. He was treated at Einstein and released to relatives Wednesday morning.
A family friend said Saa'yon suffered scrapes and bruises. He knew his mother and siblings were gone: when the crash was discussed, he would cover his ears, relatives said.
"I can't believe it. I feel like I'm in a dream," said Janice Lawson, the children's maternal great-grandmother. "They were sweet kids. They loved their mother."
Banks' stepfather, Walter Holmes, 43, said he had raised her since she was 3 - and loved her dearly.
"I'm deeply hurt," he said, surrounded by family and friends at the Banks' household on C Street. "She was a wonderful person, a great mom. She was very dedicated to her family."
Funeral arrangements were underway. Banks would be buried with her children, he said.
Tyeisha Marshall, 27, a close friend, said Banks often talked about the dangers of the Boulevard, and made sure to hold her children tight when they crossed.
"She always had her kids with her wherever she went," said Marshall, godmother to Saa'sean. "I love her and miss her so much."
Hessel, the lawyer, who has handled pedestrian fatality cases, said the city and state must do more to make the road safer.
"It is a 12-lane, confusing and complex road system," he said, noting that pedestrians must hurry to reach a safe median, then race again to a second. "Even in the best scenario pedestrians don't have enough time to cross all 12 lanes. They can only cross six lanes."
Contact Sulaiman Abdur-Rahman at firstname.lastname@example.org, or follow on Twitter @sabdurr.