[KuHS]

Код:

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
	if (vehicleid == 531) SendClientMessageToAll(COLOR_ENTERVEH, "%s entered the tractor");
	return 1;
}

public OnPlayerExitVehicle(playerid, vehicleid)
{
	if (vehicleid == 531) SendClientMessageToAll(COLOR_EXITVEH, "%s left the tractor");
	return 1;
}

Here you go.