Netcare 911 spokesperson Chris Botha said one of the taxi drivers was still trapped in the vehicle by 7.15am.
"He is in a critical condition," Botha said.
The accident happened just before 7am on the corner of Church Street and Garfield Road.
"A total of 17 people were injured. The taxi driver is critical, two people sustained serious injuries and the others all suffered minor injuries.
"Among those are four children, aged about 12 and 13, who were on their way to school," said Botha.
The cause of the accident is not known.
Church Street has been closed off.
Sapa
Ebrahim Moolla and Hadlee Simons debate whether the BRT system is really the best solution.
Rebekah Kendal wonders what it will take before someone stands up to SA's schoolyard bullies…
Do you need a laugh? Then check out our offbeat stories from around the world...