IndyCar drivers will have push-to-pass for the remaining races on road and street courses:
As part of the introduction of push-to-pass, the base turbocharger boost level will decrease to 150 kPa. When the system is engaged, the boost increases to 160 kPa on the 2.2-liter V6 engines supplied by Chevrolet, Honda and Lotus.
http://www.indycar.com/News/2012/06-June/6-27-INDYCAR-to-reintroduce-push-to-pass
I think it’s worth having for the road and street courses but I really don’t think it’s necessary for the ovals. After watching the Barber race, I’m not entirely convinced it’s needed for all the road and street tracks, though Detroit was a bit processional.