SAN FRANCISCO (KTVU) - San Francisco authorities are investigating a deadly bike collision in the city's South of Market neighborhood.
Witnesses began calling 911 at 8:19 a.m. Friday, moments after the crash.
Binod Singh was across the street as the accident unfolded. He said the woman on the electric Ford Plus bicycle was killed instantly.
"Right away," said Singh. "Then I walked over on the other side to the Subway and I looked at her, and nothing happened to her body, but only in the head."
So far this year five pedestrians have been struck and killed and now a cyclist. Cyclists, activists, concerned citizens, supervisors and the mayor alike are all pushing for change, saying it has to come now or more people will die.
Investigators spent a good portion of the morning photographing the wheels and undercarriage of the white panel truck.
Police said everyone involved in the collision stopped and remained on scene.
"This is all still under investigation. If there were multiple vehicles involved, we haven't completely determined which vehicles are involved and how many people have witnessed this," said Robert Rueca from the San Francisco Police Department.
San Francisco Supervisor Matt Haney was on scene within hours of the deadly collision, saying tragedy struck his district again this week.
"This is the second fatal crash that we've seen on our streets this week. One who was on a bike and one who was walking," said Haney. "And, so this is one of the most urgent crises that we face in our city."
Mayor London Breed spoke out just this week pushing for Vision Zero, the city-wide initiative to have zero fatal crashes in the city by 2024.
The mayor said the city is proceeding with plans to improve safety, "but while we wait for these capital improvements, we need to make short-term safety enhancements, which I have instructed the SFMTA to do without delay." Breed said Friday's collision is an example of why change is needed now.
"If we keep designing streets for fast moving cars and don't acknowledge that there is so many people walking and biking on our streets today, people will die," said Janice Li from SF Bicycle Coalition.
It did appear that the victim, identified by the medical examiner as 30-year-old Tess Rothstein of Berkeley, was riding an electric assist bicycle at the time of the collision.
The Coalition said those bikes have limits to how fast they can go, and that they seem to be getting more people out and riding in the city.
They also point out how dangerous the current bike lane situation is on Howard Street between 5th and 6th streets with cars and bikes right next to one another. They point out that if the victim had made it across the street to Howard between 6th and 7th with protected bike lanes--with parked cars between her and the truck--this collision never would have happened.
By the evening commute, cyclists and advocates with the group People Protected donned yellow t-shirts and formed a human protective barrier as an impromptu bike lane at the scene of the accident.
KTVU's Jana Katsuyama contributed to this report.