Nine drivers were at work on Wednesday, testing the aerodynamic package to be used on the new 2012 Dallara IndyCar safety cell at this year's Indianapolis 500.

Marco Andretti set the fastest time at Indianapolis Motor Speedway on a breezy, overcast day with temperatures in the mid-60s (around 18C), with a lap of 41.1664s equivalent to 218.625mph around the 2.5-mile oval.

"I had a mega tow on that lap," admitted Andretti afterwards. "The best I could by myself was 216," he said, adding that it was hardly setting the world on fire but that it was good for a first day.

While below the hoped-for 220-222mph figure that IndyCar had said they were looking for in advance of the test, it nonetheless suggests that the teams are on course to achieving the final target speed of around 225mph next month.

"That last little bit will come as teams dial the cars in to the track during the week of Indy and 225 is the target," said IndyCar's vice president of technology, Will Phillips.

"The configuration we have now is the one we intend to come back with in May," Phillips added. "We need to look at what comes out of today and see if anything further needs to be changed. We'll get some feedback from teams and drivers [about] what the car is like in traffic and what it's like on their own."

"Like anything else you have to develop it, and right now that's what we're doing," said three-time Indy 500 winner Helio Castroneves. "It's different, no question about it, because we're so used to the other car."

Tony Kanaan's final best laptime of 41.2014s (218.439mph) was not much better than he managed with an early version of the car and aerokit that ran at IMS last November, but he was still happy that it represented an improvement on the much-criticised initial state of affairs.

"They did a good job with the changes, it's 90 percent better to drive,' said Kanaan. "These cars are wider and there's a lot more turbulence," he added.

The organisers of the IZOD IndyCar Series had staged the day-long test at the Indianapolis Motor Speedway to allow teams to input into the development of the new aero kit before the specification is locked down ahead of May's race. Teams were invited to run one car each for the day, with an experienced (non-rookie) driver.

The Honda camp fielded Scott Dixon (Target Chip Ganassi Racing), Takuma Sato (Rahal Letterman Lanigan Racing), Mike Conway (AJ Foyt Racing) and Justin Wilson (Dale Coyne Racing), while Chevrolet was working with Ed Carpenter (Ed Carpenter Racing), Marco Andretti (Andretti Autosport), JR Hildebrand (Panther Racing), Tony Kanaan (KV Racing) and Helio Castroneves (Team Penske).

There were no Lotus drivers present, however. The engine manufacturer was unable to provide a sufficient number of additional engines on top of meeting the number required for forthcoming races in Long Beach and Sao Paulo, after replacement engines were needed by Oriol Servia and Alex Tagliani at Barber Motorsports Park at the weekend.

"It's a bit annoying that we're not going," said HVM's Simona de Silvestro, who has been leading much of the test and development work for Lotus to date. "It is what it is."

The teams were required to use the new-style rear-wheel guards developed especially for the DW12 to use on speedway tracks to reduce drag, but had freedom to experiment with other components and settings.

The speedway version of the oval aerokit will be used at the season finale at Auto Club Speedway, Fontana in September as well as the Indianapolis 500 next month. The original aerokit and rear-wheel guards will still be used at the remaining oval races of the 2012 season.

Practice times

1. #26 Marco Andretti (C) 218.625mph 41.1664s (51 laps)
2. #11 Tony Kanaan (C) 218.439mph 41.2014s (68 laps)
3. #10 Scott Dixon (H) 218.094mph 41.2666s (56 laps)
4. #3 Helio Castroneves (C) 216.942mph 41.4857s (56 laps)
5. #4 JR Hildebrand (C) 216.641mph 41.5434s (45 laps)
6. #18 Justin Wilson (H) 213.753mph 42.1046s (64 laps)
7. #14 Mike Conway (H) 212.767mph 42.2997s (65 laps)
8. #15 Takuma Sato (H) 212.573mph 42.3384s (57 laps)
9. #20 Ed Carpenter (C) 207.518mph 43.3697s (33 laps)

Total Laps for Combined Sessions: 495