Last year's winner Helio Castroneves set the pace as practice for the 2010 Indianapolis 500 began this afternoon.
Under the truncated 2010 schedule, the opening day started with two hours for experienced drivers, before the remainder of the afternoon was given over to rookies and drivers eligible for "refresher" testing.
It was Ganassi duo Dario Franchitti and Scott Dixon who set the early pace, and started producing laps in excess of 226mph -- some 2mph below the 2009 pole speed -- almost immediately. That looked set to keep them comfortably on top of the timing screens, until Penske driver Castroneves averaged 226.603mph on a late run.
Dan Wheldon showed good early form for Panther Racing in fourth, ahead of Tony Kanaan. The Brazilian had a busy afternoon - shaking down the cars of his Andretti Autosport teammates Ryan Hunter-Reay, Danica Patrick, Marco Andretti and John Andretti to establish a baseline for all five entries before getting his own program under way.
The 12 drivers in the rookie and refresher category now have the track to themselves until 6 p.m. local time. Sunday's practice follows the same format, before the full field takes to the track together on Monday.