It’s like JFK or Princess Diana dying: almost everyone in America old enough remembers where they were the day of the OJ Simpson white Bronco freeway chase.

Twenty years later, it remains an iconic TV moment.

Some 95 million Americans watched the slow-speed chase live on television on June 17, 1994, as the NFL megastar went on the run following the double murder of his ex-wife Nicole Brown and her friend Ronald Goldman.

The anniversary on Tuesday is being marked by a resurgence of memories of the motorcade, and the trial that followed, the first followed by a mass international audience in real time.

The day’s events started with police announcing that OJ was the chief suspect in the murder of his ex-wife and Goldman, whose bloodied bodies had been found four days previously.

Hours later, Simpson was located driving along the 5 freeway outside Los Angeles with his football friend Al Cowlings. The star had a gun which authorities feared he would use to kill himself.

Some TV stations broke into coverage of game five of the NBA finals to transmit the unfolding real-life drama.

“There are some watershed moments in American culture that kind of transform the way we view the world, and I think that chase was certainly one of those moments,” said legal expert Marcellus McRae.

“It was a surreal spectacle. It was almost Shakespearian. It was a reality show,” he told AFP.

TV viewers were hypnotised by the story because “it’s not Hollywood, it’s real life and it’s someone that you actually know”, he added.

“Regardless of who you are, what your socio-economic background is, whether you are male or female, if you are black or white or Latino, you were riveted by what was happening.”

Live TV coverage showed dozens of police cars following Simpson’s white Bronco at slow speed, while thousands of bystanders gathered on bridges and on the side of the freeway to watch the procession.

The chase was ideally suited for real-time, round-the-clock TV coverage, which was still in its infancy two decades ago, said journalist Jim Newton, who covered it for The Los Angeles Times.

The story combined “a double murder with a big name”, creating a “very tense” situation.

“Attention and interest had been growing in the case for several days,” he told AFP.

“It was a precursor of the reality show,” he added.

Moreover, “Simpson really divided people … there were opposing feelings,” he said, comparing it to the Michael Jackson child molestation claims and trial, in terms of public debate and controversy.

“My family admired him. We stayed at home all day to see whether he would commit suicide or surrender,” said 29-year-old Kyra, a waitress in a Hollywood restaurant.

Television news helicopters followed the pursuit all the way to the gates of Simpson’s house, where he gave himself up after hours of negotiations with police.

The blanket media coverage continued during Simpson’s criminal trial, which began in January 1995, lasted for nine months and drew more than 2,000 journalists from around the world.

The trial provided iconic moments itself, including when the former sports star tried on a bloodied glove found at the scene of the crime – which turned out to be too small, undermining a key prosecution claim.

The day of the verdict, October 3 1995, 145 million tuned in to see him declared not guilty on all charges.

His fans took to the streets to celebrate, while critics accused the jury of ignoring DNA evidence, and pointed out that 10 of the deciding panel’s 12 members were African American, like Simpson himself.

Controversy over the case returned two years later, when he was ordered to pay $US33.5 million ($A36.25 million) to the families of the victims following a civil trial in Santa Monica, just outside Los Angeles.

Simpson’s problems with the law did not end there. In 2007 he was arrested for alleged armed robbery and kidnapping in Las Vegas, along with a group of men.

He was eventually found guilty and sentenced to between nine and 33 years behind bars, a jail term he has been serving in Nevada since 2008.