Racing figures called on Formula One to re-examine safety procedures after Felipe Massa sustained life-threatening skull injuries in a high-speed accident during Hungarian Grand Prix qualifying.
The 28-year-old Ferrari driver was in stable condition in the intensive care unit of a military hospital following surgery on Saturday.
Massa slammed into the protective tire barriers at Hungaroring at a speed of about 120 mph after being struck in the helmet by a loose spring. The common car part had fallen out of the rear suspension of Rubens Barrichello's Brawn GP car.
It was the second accident in six days where track debris struck a driver in the helmet to cause an accident. F2 driver Henry Surtees died in an incident last Sunday.
"Things happen for a reason and I think this is the second message. Imola was a message," said Barrichello in reference to 1994's San Marino GP, where three-time champion Ayrton Senna died from a nearly identical accident as fellow Brazilian Massa.
Barrichello was knocked unconscious at that race after a dramatic crash that flipped his Jordan car.
"It is not a coincidence that something happened right now. In the (drivers' meeting) we talked quite a lot about it (on Friday) and something needs to be done," the 37-year-old Brazilian said. "Yes, absolutely."
Surtees, the son of former F1 champion John Surtees, died after being struck in the head by a tire from another car, causing him to lose consciousness and drive into a barrier.
"From what's been seen last weekend and this weekend we need to have a proper study. There's a need to do something," Brawn GP team principal Ross Brawn said. "We need to digest what's happened and understand it properly."
A worrying concern for F1 medical staff will be that Massa suffered a fracture to the base of his skull as well as the front. The impact ripped out the visor, and left a long dent on its side, while blood was seen above Massa's left brow.
Since 2003, F1 has made it mandatory for drivers to wear the Head and Neck Support system (HANS), a carbon fiber device that is supposed to keep drivers from suffering skull fractures in high speed crashes like Massa's.
For former F1 driver Juan Pablo Montoya, the medical response time was "shocking."
"It was incredible. We always complained when I was there," Montoya told The Associated Press at Indianapolis. "It was kind of shocking."
Criticism emerged last year after the FIA needed nearly 10 minutes to pry Heikki Kovalainen from his McLaren car after it slammed into a tire wall at about 80 mph.
Massa's incident also came while several drivers were critical of Toro Rosso's promotion of Jaime Alguersuari to a race seat for the Hungarian GP, even though the 19-year-old Spaniard had never driven an F1 car before.
Brawn said calm should rule since F1 has always taken safety issues seriously, even as the ban on in-season testing means that more inexperienced drivers would likely be coming into the series in the future.
"If there's a need to react, Formula One will react very promptly. Let's just make sure we don't do something to make the situation worse," Brawn said. "We need to understand what happened and then we can react accordingly tomorrow."
AP Auto Racing Writer Jenna Fryer contributed to this report.