Autosport can reveal more details on how the halo passed its first significant test in a live race situation last weekend at Barcelona.
Formula 2 driver Tadasuke Makino said the device - which was a controversial addition to F1 and F2 cars for this year because of its aesthetics - saved his life in his accident with Nirei Fukuzumi during Sunday's sprint race.
Autosport has now obtained images clearly showing how close the rear wheel of Fukuzumi's car came to Makino's head, illustrating how the halo did its job of protecting the driver inside the cockpit when they collided at Barcelona's Turn 4.
Makino said: "The first time I tested this car I didn't think the halo was good, because it's difficult to see anything, but today the halo helped me.
"It's really important. I understand how the halo works now.
"I don't know what happened, but without the halo I think the tyre would have hit my helmet.
"It was a big surprise, the halo was a big help for me."
F1 and F2 race director Charlie Whiting added: "Even if it didn't actually save his life it could have been nasty without the halo, judging by the [tyre] tracks."