**Exhibit 8.1**

 

**List of Main Subsidiaries**

 
| **Subsidiaries**                                                                                                  | ** ** | **Jurisdiction** |
|-------------------------------------------------------------------------------------------------------------------|------------|------------------|
| *Grupo   Concesionario de México S.A. de C.V.*                                                               | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Promotora   y Administradora de Carreteras, S.A. de C.V.*                                                        | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Promotora   de Autopistas del Pacífico, S.A. de C.V.*                                                       | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Concesionaria   Pac, S.A. de C.V.*                                                                               | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Autopista   Tenenago-Ixtapan de la Sal, S.A. de C.V.*                                                            | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Concesionaria   Monarca, S.A. de C.V.*                                                                           | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Infraestructura   Portuaria Mexicana, S.A. de C.V.*                                                              | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Concesionaria   Zonalta, S.A. de C.V.*                                                                           | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Tribasa   Sector Materiales e Insumos de la Construcción S.A. de C.V.*                                      | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Grupo   Corporativo Interestatal, S.A. de C.V.*                                                                  | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Tribasa   Construcciones, S.A. de C.V.*                                                                          | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Pinfra   Sector Construcción S.A. de C.V.*                                                                  | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Experconstructores   Zacatecana, S.A. de C.V. (formerly Triturados Basálticos y Derivados, S.A. de   C.V.)* | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Adepay,   S.A. de C.V.*                                                                                          | * *   | Mexico           |
| * *                                                                                                          | * *   |             |
| *Equivent,   S.A. de C.V.*                                                                                        | * *   | Mexico           |

 

----