A boy of 14 jumped off a bridge spanning the Ostend Brussels Motorway (E40) on Wednesday morning.
The incident happened at Ternat, just outside the Belgian capital.
The boy ended up under the wheels of a lorry and was dead at the scene.
The incident created traffic chaos on the way into and out of Brussels. Two of the three carriageways in the direction of Ostend were closed for a while.
The youngster went to a technical school in Liedekerke (Flemish Brabant). The school is giving a news conference in the