Scott Dixon posted the fastest lap during practice at Indianapolis on Thursday. (INDY photo by Matt Fraver)

NTT IndyCar Series point-leader Scott Dixon moved to the top of the speed chart at Indianapolis Motor Speedway Thursday, the second day of practice for the 104th running of the Indianapolis 500.

The 2008 race champion, Dixon toured the 2.5-mile oval in 39.8050-seconds/226.102 mph in the No. 9 Chip Ganassi Racing Honda. His fast lap came with the benefit of an aerodynamic tow, as drivers continued to refine race setups in traffic.

Dixon, who opened the 2020 season with three straight victories, jumped into P1 after recording the third-fastest speed Wednesday at 224.047 mph. A five-time series champion, Dixon looms as a prime contender for both pole position during Armed Forces Qualifying Weekend this Saturday and Sunday and for his second Indy 500 victory on Sunday, Aug. 23. NBC’s live Indy 500 broadcast is scheduled to begin at 1 p.m. (EDT), with the green flag set for 2:30 p.m.

“Today, we made some minor changes and tried to figure out some different balances,” Dixon said. “We’re also focusing on how the car feels. The No. 8 car had some changes yesterday that (teammate Marcus Ericsson) liked and we tried them, but I’m on the fence. We’re just running through those variations and trying to run in as much traffic as possible and get the car as comfortable as possible for the race.

“We’re really just working hard on race setup. We’ve had a lot of options to work through, and we also wanted to run some of the things the other two cars have tried. We also worked on finding traffic today to see how the car would respond.”

Takuma Sato, the 2017 Indy 500 champ, was second overall at 225.693 mph in the No. 30 Honda fielded by Rahal Letterman Lanigan Racing. Marco Andretti ranked third at 225.249 mph in the No. 98 U.S. Concrete/Curb Honda entered by Andretti Herta Autosport with Marco & Curb-Agajanian.

Conor Daly was the fastest Chevrolet-powered driver, fourth overall at 225.106 mph in the No. 47 entry fielded by Ed Carpenter Racing. Rookie Alex Palou rounded out the top five and another strong day for Honda-powered teams at 224.971 mph in the No. 55 Dale Coyne Racing with Team Goh Honda.

“Today was another step forward for us,” said Daly, who is working with former NASCAR championship-winning crew chief Cole Pearn. “Cole (Daly’s engineer) and I are figuring out what I need and what he wants to do. We’re definitely close to where we want to be, but that becomes a difficult area to work in. Cole doesn’t have the experience yet and I really don’t have the experience to know exactly what we need. We’re trying to mess around with some things and figure out what we can do next to make it even better. I like where the U.S. Air Force Chevy is at. It’s fast. We don’t want to out-engineer ourselves; we’re going to keep our heads on straight and keep on trucking.”

Jack Harvey was the fastest driver without an aerodynamic tow, with a top solo lap of 222.124 mph in the No. 60 Honda fielded by Meyer Shank Racing.

Meanwhile, two-time Formula One World Driving Champion Fernando Alonso was uninjured in the week’s first accident at 4:40 p.m. _ 50 minutes before the end of practice. Alonso made right-side contact with the SAFER Barrier exiting Turn 4 after clipping the concrete apron with the left front wheel of his No. 66 Arrow McLaren SP Chevrolet. The car completed a half-spin to the left at pit entry and slid into the inside pit wall, making secondary right-front contact. The car suffered moderate damage.

Alonso, who also crashed in practice last year and subsequently was bumped from the 33-car field, was eighth-fastest at 224.363 mph before his accident.

“It was the car, the grip of the car,” said Alonso, the 2017 Indy 500 Rookie of the Year. “This place, the walls are coming very close. This is the way it is. Unfortunately, it happened again today. Hopefully it happens today instead of Sunday the 23rd.

“You learn every lap you do around here, and we learned from this. Tomorrow we start again. I think everything is going to be OK. Let’s keep up the good work, and hopefully no more issues.”

Ben Hanley completed the first phase of his refresher test after practice in the No. 81 DragonSpeed USA Chevrolet. Hanley will attempt to finish the final phase Friday.

Practice is scheduled to continue from 11 a.m.-5:30 p.m. (EDT) Friday for all drivers, with live coverage on INDYCAR Pass on NBC Sports Gold. Cars will receive increased turbocharger boost _ generating approximately 50 horsepower and higher speeds _ on “Fast Friday” in preparation for time trials on Saturday and Sunday.

“It’s going to be cool,” said Dixon, whose 46 career victories are most among active series drivers and third all-time. “It’s a big jump (in power). We’re pretty low speeds (Thursday). I expect to see some pretty big speeds tomorrow, especially in tows. Everybody will be trying to get a clear track, but that’s going to be tough to get. I’m excited for tomorrow _ Fast Friday.”