IndyCar president of competition Derrick Walker has resigned, effective at the end of the season.

Walker will stay on for the final three races, which ends Aug. 30 in Sonoma, California. Walker says the timing is right to move on to other opportunities after 2½ seasons on the job.

He helped IndyCar land Boston as a new race in 2016, helped introduce a road course race at Indianapolis Motor Speedway and made contributions in race control and aero kits.

Walker has been in involved in racing in more than 40 years, in several series, including team ownership.

However, Walker had come under fire for problems this year with the aero kits after three Chevrolet cars went airborne before the Indianapolis 500. IndyCar then changed the qualifying rules to help Chevy, which angered rival manufacturer Honda.