Former world champion Nigel Mansell says IndyCar can learn from Formula 1 after the death of Dan Wheldon.
Briton Wheldon, 33, was involved in a 15-car crash in a race in Las Vegas.
Some IndyCar contests take place on oval circuits surrounded by a perimeter wall, while F1 races usually employ barriers well away from the track.
Mansell told BBC Radio 5 live: "In Indy racing there is simply nowhere to go. When an accident happens you are into the wall in a split second."
Mansell, who won the F1 world title in 1992 and the IndyCar equivalent a year later, added: "This is why Formula 1 does an exemplary job. The tarmac runs off so the driver has time to decelerate the car."
Mansell said: "To have 34 cars travelling at at 220mph on a mile-and-a-half long circuit, there are too many cars on the track.
"The trouble is there are no small accidents when accidents happen. There were a number of rookie drivers and others driving in their first race of the season.
"I heard Jody and he said it well. The smallest mistakes turn into catastrophic ones and Dan was on the receiving end of it."
Derek Warwick, president of the British Racing Drivers' Club and a former F1 driver, claims that a host of changes are needed in IndyCar racing.
Warwick echoes Mansell's criticism of the number of cars on the track and feels that F1 is safer because their drivers are better.
He told 5 Live Sport: "They do an enormous amount but they need to understand the quality of the drivers that are in the field as well.
"With Formula 1 the drivers that go into a Formula 1 race are all great drivers who have won championships from working their way up from Formula 3 to GP2 before they get a super licence to be able to race.
"I sometimes question the depth of talent in IndyCar races and that will lead to inexperience and the inexperienced generally end up having accidents. They need to tweak what they're doing a little bit."
