For the 2015 IndyCar Series season Dallara prepared their first facelift aero kits for the DW12 designed by them, in partnership with Wirth Research for Honda, and Pratt & Miller for Chevrolet. The original fourth generation Dallara IndyCar, the IR12, was introduced in 2012, when Dallara began providing the common monocoque and suspension parts for the new IndyCar formulae – known as the IndyCar Safety Cell – with the intent that the bodywork and aero parts can and will be provided by other manufacturers. 2011 Indianapolis 500 winner Dan Wheldon carried out the first official test of the Dallara IR12 chassis at Mid-Ohio in August 2011. Following Wheldon’s death at the season-ending race in Las Vegas, Dallara renamed the 2012 chassis the DW12 in his honor. The original IR12 (DW12) was later known as MkI, and was used for three seasons – in 2012-2014. The facelift version of DW12 was designated as MkII, and raced in the series another three seasons – in 2015-2017. In the first season of use, especially in its first half, the Chevrolet aerokits proved dominant, with Chevrolet powered teams winning 8 out of first 10 races of the season. Midway through the season, both manufacturers introduced an update to the aerokit with the Honda kit losing its front wing endplates on safety grounds, while Chevrolet introduced an additional winglet. The balance shifted in favor of Honda-powered cars (4 wins in last 6 races of the year).
In 2015 Andretti Autosport fielded a three Honda-powered car full season effort with Marco Andretti, Ryan Hunter-Reay and Carlos Muñoz. Additionally, Simona de Silvestro and Justin Wilson each joined for races throughout the season. The team scored three wins – Muñoz in the first race at Detroit, and Hunter-Reay at Iowa and Pocono speedways. Hunter-Reay, the 2012 IndyCar Series Champion, finished 6th in the final point standings with 436 points.
|Ryan Hunter-Reay||28||Andretti Autosport|
|Dallara DW12 (IR12) Mk. II||Honda||DHL|