The Verizon IndyCar Series has followed through on its promise of introducing new measures to address outspoken comments from drivers critical of the championship such as those that followed in the wake last month's event in Fontana, California.

Several drivers spoke out about the high-speed, close-quarters 'pack racing' that broke out at Auto Club Speedway, with reigning series champion Will Power describing the race as "insane" and his Penske team mate Juan Pablo Montoya calling it "crazy".

Veteran Ganassi driver Tony Kanaan concurred, calling Fontana "a crazy race" and "nerve-racking" for the drivers while Marco Andretti afterwards declared that the race had been "extremely dangerous." Several drivers raised the spectre of IndyCar's darkest hour, the race at Las Vegas Motor Speedway in 2011 in which a 13-car wreck ended in the death of Indy 500 champion Dan Wheldon.

"It was pack racing. It was Las Vegas again," said Power immediately after the race on June 27. "We don't need another Vegas incident [but] it's just a matter of time."

All that criticism was too much for Mark Miles, CEO of IndyCar's parent company Hulman & Co., who said a few days after the Fontana race that "Comments can be damaging to the interest of the whole, and I personally think our sport has been probably too lax in that regard."

As a result, the officials have now introduced a new five-part section 9.3.8 to the IndyCar Series rulebook, which reads:

Detrimental Competitor Conduct - Competitors must be respectful, professional, fair and courteous to others. At all times, Competitors must not, attempt to, or engage in conduct or statements that in the judgement of IndyCar:

a) Threatens or denigrates any Official, fellow Competitor or the IndyCar brand;

b) Calls into question the integrity or legitimacy of the Rules or their application, construction or interpretation;

c) Denigrates the IndyCar Series racing schedule or Event(s);

d) Threatens or denigrates any IndyCar business relationship, including those with sponsors or broadcasters;

e) Otherwise threatens the integrity, reputation or public confidence of the sport, IndyCar, or IndyCar Series.

The measures appear to go much further than the previous rules against "conduct detrimental to the sport" but notably do not actually stipulate any specific punishments, penalties or fines for breaches of the expanded rule in the future.

The announcement did not go down well among many fans or the media, with respected motorsports journalist Marshall Pruett writing in that "the series has apparently limited its paddock to answers that are neutral or positive."

Drivers and teams also made various barbed references about the new rule on social media, while being understandably very careful not to be the first to fall foul of the new sanctions in the process.

However Miles was quick to insist that the new rule was not intended to clamp down on all public criticism of the series, and that it "will not be imposed in a Draconian way" by series officials.

"This rule is not a gag order," he said. "We recognise that controversy, tension and drama all have a place in motorsport today. Our drivers are competitors and we have no interest in eliminating the emotion and passion that is an integral part of our sport - or limit the content for media covering IndyCar.

"We feel it's our responsibility to distinguish between irresponsible statements that damage the sport or its competitors and the intense competitive nature of the series. This rule is to ensure we have authority to act when we feel it is required."

Miles pointed out that for example, there would be no action taken over a pit lane confrontation that occurred after Saturday night's race at Iowa Speedway between Ed Carpenter and Sage Karam. Carpenter had blasted the rookie's lack of respect on track for other competitors.

"If it wasn't for guys with experience driving with their heads on he would be hurting himself and other people. I think it's ridiculous," said Carpenter on the night. "I'm just mad because I had a car that was good enough for third or fourth and I do safe driving - slam on the brakes on the straightaway to save Sage's butt and he gets rewarded with a podium for it."

The hot-tempered exchange between the pair had been captured by TV reporters on the scene, but Miles said that this was a good example of the sort of thing that the new Detrimental Competitor Conduct rule would not be used to sanction in the future.

"Some have speculated that the exchange between Ed Carpenter and Sage Karam last Saturday at Iowa Speedway would result in penalty under this new rule," Miles noted. "That is not the case. We feel exchanges of that manner do not cross the line and instead highlight the intensity of Verizon IndyCar Series competition."

Unfortunately Miles' insistence that officials will use "good judgement" over such issues means that competitors and stakeholders will now face a period of uncertainty over exactly where the dividing line between acceptable comments and unacceptable criticism actually lies.

"There's no limits on a driver or competitor disagreeing with our judgement," elaborated IndyCar's president of operations and competition, Derrick Walker in comments to The Indianapolis Star on Tuesday, explaining that the new rule was in place to stop those involved in the sport from spoiling the brand by "degrading it."

"You can't say IndyCar is all screwed up [or that] it doesn't know what it is doing," Walker said. "There's no sport where you can do that."