INDYCAR president of operations Brian Barnhart cited team owners' concerns over costs, as well as the DW12's stellar performance on the track, as reasons for the decision.
"We listened to the owners talk about the need to reduce the cost of participation, and one of the ways of doing that is to examine the testing rules that were allowed and necessary in 2012 and revising them for 2013," Barnhart said in a league statement.
"With the car performing as well as it did and the competition at a high level, there simply isn't the need for as much testing. Teams will benefit from a sizable cost reduction through this more restrictive testing plan."
Manufacturers will be limited to two days of private testing in both the offseason (before Dec. 31) and pre-season (Jan. 4, 2013 to the Honda Grand Prix of St. Petersburg on March 24, 2013) periods. In-season manufacturer test days have been cut from six to four, with a rule of two manufacturer days per team.
As for teams, they'll only get two days of private testing across all periods -- off-season, pre-season, and in-season -- as well as four total engine manufacturer test days each. In addition, full-season programs will receive 16 sets of tires (half as much as they got in 2012) for private test days. Teams and drivers that are new to the series shall have a handful of additional days and sets of tires to work with.
Four Open Tests are slated to take place during the season at Indianapolis Motor Speedway (April), Barber Motorsports Park (race week in early April), Mid-Ohio Sports Car Course (early August), and Sonoma Raceway (late August). A pre-season Open Test site has yet to be determined.
Finally, full-size wind tunnel testing will be restricted to two days per team and four days per engine manufacturer; model wind tunnel testing is permitted.