INDYCAR have implemented an update to Push to Pass usage procedures for the NTT INDYCAR SERIES and INDY NXT by Firestone. This follows a review of the software failure that occurred during the Acura Grand Prix of Long Beach on the 19th April.
The Software Failure
The system is intended to transmit signals to each car individually. These signals deliver telemetry data including running order, lap-gap intervals, time differences to the race leader, and Push to Pass status and availability. It is a driver-controlled system that provides roughly 60 extra horsepower via increased turbocharger boost.
Just before the full-course yellow and immediately after the Lap 61 restart, the INDYCAR software accidentally issued simultaneous CAN (Controller Area Network) signals. These signals went to the receivers installed in the cars on track.
Because the signals were transmitted simultaneously, the Push to Pass system shut down. As a result, the cars never received the signals to deactivate Push to Pass. Therefore, the system remained active during the full-course yellow and the restart that followed.
After reviewing the findings, INDYCAR Officiating determined that neither the teams nor the drivers committed an infraction. Although drivers used the system during the restart, the official results remain unchanged following this decision.
What Has Changed
INDYCAR will introduce the changes during the May 8-9 event on the Indianapolis Motor Speedway road course. The updated and corrected code will be used for the CAN messages. This will include a “lock” around the sequence of events that writes the message to the servers.
The revised code now sends messages one at a time, preventing simultaneous signal transmissions. The “lock” is common in racing systems, and it does not affect the functionality or reliability of the software.
INDYCAR completed internal testing on the updated code, including additional validation during the Indy 500 Open Test on Tuesday and Wednesday, April 28-29. The system operated without issue throughout testing and recorded zero errors.
“The Independent Officiating Board would like to thank INDYCAR’s software and powertrain engineers who have helped us work through this review,” Chairman of the INDYCAR Officiating Board, Raj Nair, commented following the change.
It now also has expanded availability. This now allows Push to Pass use during race restarts, and will give teams and drivers additional opportunities to overtake during one of the most critical phases of a race.
Drivers may activate the system once they pass the alternate start-finish line following the start or after the green flag waves on a restart. The rule prohibiting passing before the restart line will remain in effect.