The defending race winner, Kirkwood delivered a flying lap of 1m06.4731s (106.581 mph) in the final seconds to lead the session on a chilly morning at the 11-turn, 1.968-mile temporary street circuit.
Herta, who led the majority of the second half of the session, ended up trailing by 0.0155s behind Kirkwood.
Christian Lundgaard also took advantage of a late run and jumped to third, 0.1100s off the top mark.
Meyer Shank Racing’s Felix Rosenqvist and Team Penske’s Scott McLaughlin came away fourth and fifth, respectively.
The opening 15 minutes saw the top spot rotate between Josef Newgarden and Pato O’Ward before McLaughlin extracted a quick lap of 1m07.2463s.
While McLaughlin and Newgarden were at the top, their Team Penske team-mate Will Power hit trouble after tapping the wall in Turn 8 led to bent suspension on his left-rear corner.
After Chevrolet appeared to own the leaderboard for at the beginning of the session, Honda then took its turn with Andretti Global’s Colton Herta nailing a quick lap of 1m06.4886s to vault to first with roughly 25 minutes to go.
Kirkwood shook off the electrical issues that plagued him in opening practice and jumped to second just 0.1393s behind team-mate Herta.
Reigning and two-time champion Alex Palou elevated his No. 10 Chip Ganassi Racing Honda to third, 0.2779s off the time set by Herta.
Heads up, rookie 😮
— NTT INDYCAR SERIES (@IndyCar) April 20, 2024
Slight contact for @TPourchaire coming out of Turn 4.
📺: Peacock pic.twitter.com/CGA1W1R05p
Theo Pourchaire, making his IndyCar debut this weekend in the No. 6 Arrow McLaren Chevrolet substituting for the injured David Malukas, was already ahead of his opening practice pace out of the gate.
The reigning Formula 2 champion established the improvement with an early run of 1m07.3934s but did go over the limit after tapping the wall in Turn 4 and hit left-rear and then left-front before continuing on with 23 minutes to go. He finished up 19th overall, 1.0203s off the pace.
McLaughlin was able to break up the Honda trifecta at the top with 12 minutes to go, jumping to third and pushing Palou down a spot with a run that was 0.2473s off the top time.
Power was able to return to practice but found trouble in Turn 8 once more to bring out the red flag with less than nine minutes to go. After receiving assistance from the AMR IndyCar Safety Team, the Aussie was able to refire and continue on and return to the pits. Prior to the incident, Power was able to put down a lap 1m06.8099s to run sixth on the timesheets.
The contact with the wall led to Power getting out of the car to put an early end to his session. He would end up eighth overall when the checkered flag fell.
A frustrating session for the No. 12.@12WillPower brings out the red flag following another incident in Turn 8. pic.twitter.com/vPEmzGTNjS
— NTT INDYCAR SERIES (@IndyCar) April 20, 2024
After the session restarted, traffic became a maze for drivers eager to find the maximum pace as everyone stacked up near Turn 11.
However, Lundgaard was able to fire off a quick lap of 1m06.5831s to jump his No. 45 Rahal Letterman Lanigan Racing Honda to second in the final minute.
Kirkwood propelled to the top spot in the final seconds, pushing down Herta to second and Lundgaard to third at the conclusion of practice.
| Cla | Nº | Driver | Car / Engine | Time | Gap | Laps |
| 1 | 27 | Kyle Kirkwood | Dallara/Honda | 1'06.4731 | 24 | |
| 2 | 26 | Colton Herta | Dallara/Honda | 1'06.4886 | 0.0155 | 25 |
| 3 | 45 | C.Lundgaard | Dallara/Honda | 1'06.5831 | 0.1100 | 21 |
| 4 | 60 | Felix Rosenqvist | Dallara/Honda | 1'06.6518 | 0.1787 | 22 |
| 5 | 3 | Scott McLaughlin | Dallara/Chevrolet | 1'06.7359 | 0.2628 | 23 |
| 6 | 10 | Alex Palou | Dallara/Honda | 1'06.7665 | 0.2934 | 26 |
| 7 | 77 | Romain Grosjean | Dallara/Chevrolet | 1'06.7988 | 0.3257 | 22 |
| 8 | 12 | Will Power | Dallara/Chevrolet | 1'06.8099 | 0.3368 | 11 |
| 9 | 78 | Agustín Canapino | Dallara/Chevrolet | 1'06.9552 | 0.4821 | 22 |
| 10 | 7 | Alexander Rossi | Dallara/Chevrolet | 1'07.0128 | 0.5397 | 24 |
| 11 | 11 | Marcus Armstrong | Dallara/Honda | 1'07.0451 | 0.5720 | 23 |
| 12 | 9 | Scott Dixon | Dallara/Honda | 1'07.0713 | 0.5982 | 27 |
| 13 | 2 | Josef Newgarden | Dallara/Chevrolet | 1'07.1578 | 0.6847 | 22 |
| 14 | 15 | Graham Rahal | Dallara/Honda | 1'07.1617 | 0.6886 | 25 |
| 15 | 21 | R.van Kalmthout | Dallara/Chevrolet | 1'07.1635 | 0.6904 | 20 |
| 16 | 20 | C.Rasmussen | Dallara/Chevrolet | 1'07.1792 | 0.7061 | 23 |
| 17 | 28 | Marcus Ericsson | Dallara/Honda | 1'07.2638 | 0.7907 | 25 |
| 18 | 66 | Tom Blomqvist | Dallara/Honda | 1'07.4126 | 0.9395 | 22 |
| 19 | 6 | Théo Pourchaire | Dallara/Chevrolet | 1'07.4934 | 1.0203 | 23 |
| 20 | 30 | P.Fittipaldi | Dallara/Honda | 1'07.5035 | 1.0304 | 22 |
| 21 | 5 | Patricio O'Ward | Dallara/Chevrolet | 1'07.5127 | 1.0396 | 31 |
| 22 | 8 | Linus Lundqvist | Dallara/Honda | 1'07.5232 | 1.0501 | 27 |
| 23 | 51 | Nolan Siegel | Dallara/Honda | 1'07.9285 | 1.4554 | 24 |
| 24 | 18 | Jack Harvey | Dallara/Honda | 1'07.9481 | 1.4750 | 23 |
| 25 | 4 | Kyffin Simpson | Dallara/Honda | 1'08.2015 | 1.7284 | 25 |
| 26 | 41 | Sting Ray Robb | Dallara/Chevrolet | 1'08.7330 | 2.2599 | 21 |
| 27 | 14 | Santino Ferrucci | Dallara/Chevrolet | 1'09.0933 | 2.6202 | 6 |
