| << 2017 | 2019 >> |

| # | pic | Versenyző | Nemz. | Autó | Csapat | Chassis/motor |
| 1 | Josef Newgarden | USA |
| Team Penske | Dallara IR18 - Chevrolet | |
| 4 | Matheus Leist (R) | Brazil |
| A.J. Foyt Enterprises | Dallara IR18 - Chevrolet | |
| 5 | James Hinchcliffe | Kanada |
| Schmidt Peterson Motorsports | Dallara IR18 - Honda | |
| 6 | Robert Wickens (R) | Kanada |
| Schmidt Peterson Motorsports | Dallara IR18 - Honda | |
| 9 | Scott Dixon | Új-Zéland |
| Chip Ganassi Racing | Dallara IR18 - Honda | |
| 10 | Ed Jones | Dubai |
| Chip Ganassi Racing | Dallara IR18 - Honda | |
| 12 | Will Power | Ausztrál |
| Team Penske | Dallara IR18 - Chevrolet | |
| 14 | Tony Kanaan | Kolumbia |
| A.J. Foyt Enterprises | Dallara IR18 - Chevrolet | |
| 15 | Graham Rahal | USA |
| Rahal Letterman Lanigan Racing | Dallara IR18 - Honda | |
| 18 | Sebastien Bourdais | Francia |
| Dale Coyne Racing with Vasser-Sullivan | Dallara IR18 - Honda | |
| 19 | Zachary Claman DeMelo (R) | Kanada |
| Dale Coyne Racing | Dallara IR18 - Honda | |
| 19 | Pietro Fittipaldi (R) | Brazil |
| Dale Coyne Racing | Dallara IR18 - Honda | |
| 19 | Santino Ferrucci (R) | USA |
| Dale Coyne Racing | Dallara IR18 - Honda | |
| 20 | Jordan King (R) | Angol |
| Ed Carpenter Racing | Dallara IR18 - Chevrolet | |
| 20 | Ed Carpenter | USA |
| Ed Carpenter Racing | Dallara IR18 - Chevrolet | |
| 21 | Spencer Pigot | USA |
| Ed Carpenter Racing | Dallara IR18 - Chevrolet | |
| 22 | Simon Pagenaud | Francia |
| Team Penske | Dallara IR18 - Chevrolet | |
| 23 | Charlie Kimball | USA |
| Carlin | Dallara IR18 - Chevrolet | |
| 26 | Zach Veach (R) | USA |
| Andretti Autosport | Dallara IR18 - Honda | |
| 27 | Alexander Rossi | USA |
| Andretti Autosport | Dallara IR18 - Honda | |
| 28 | Ryan Hunter-Reay | USA |
| Andretti Autosport | Dallara IR18 - Honda | |
| 30 | Takuma Sato | Japán |
| Rahal Letterman Lanigan Racing | Dallara IR18 - Honda | |
| 32 | Rene Binder (R) | Ausztria |
| Juncos Racing | Dallara IR18 - Chevrolet | |
| 32 | Kyle Kaiser (R) | USA |
| Juncos Racing | Dallara IR18 - Chevrolet | |
| 32 | Alfonso Celis Jr. (R) | Mexikó |
| Juncos Racing | Dallara IR18 - Chevrolet | |
| 59 | Max Chilton | Angol |
| Carlin | Dallara IR18 - Chevrolet | |
| 88 | Gabby Chaves | Kolumbia |
| Harding Racing | Dallara IR18 - Chevrolet | |
| 88 | Colton Herta (R) | USA |
| Harding Racing | Dallara IR18 - Chevrolet | |
| 98 | Marco Andretti | USA |
| Andretti Herta Autosport w/ Curb-Agajanian | Dallara IR18 - Honda |
| # | pic | Versenyző | Nemz. | Autó | Csapat | Chassis/motor |
| 3 | Helio Castroneves | Brazil |
| Team Penske | Dallara IR18 - Chevrolet | |
| 7 | Jay Howard | USA |
| SPM / AFS Racing | Dallara IR18 - Honda | |
| 8 | Patricio O'Ward (R) | Mexikó |
| Harding Racing | Dallara IR18 - Chevrolet | |
| 13 | Danica Patrick | USA |
| GoDaddy/Ed Carpenter Racing/DRR | Dallara IR18 - Chevrolet | |
17 88 |
Conor Daly | USA | ![]()
| Dale Coyne Racing dba Tom Burns Racing Harding Racing |
Dallara IR18 - Honda Dallara IR18 - Chevrolet |
|
| 24 | Sage Karam | USA |
| Dreyer & Reinbold Racing | Dallara IR18 - Chevrolet | |
| 25 | Stefan Wilson (R) | Angol |
| Andretti Autosport | Dallara IR18 - Honda | |
29 6 |
Carlos Munoz | Kolumbia | ![]()
| Andretti Autosport Schmidt Peterson Motorsports |
Dallara IR18 - Honda Dallara IR18 - Honda |
|
| 33 | James Davison | Ausztrál |
| Foyt with Byrd/Hollinger/Belardi | Dallara IR18 - Chevrolet | |
| 39 | Santino Ferrucci (R) | USA |
| Dale Coyne Racing | Dallara IR18 - Honda | |
60 |
Jack Harvey (R) | Angol |
| Meyer Shank Racing with SPM | Dallara IR18 - Honda | |
63 |
Pippa Mann | Angol |
| Dale Coyne Racing | Dallara IR18 - Honda | |
64 |
Oriol Servia | Katalán |
| Scuderia Corsa with RLL Racing | Dallara IR18 - Honda | |
66 |
JR Hildebrand | USA |
| Dreyer & Reinbold Racing | Dallara IR18 - Chevrolet |