<xs:complexType name="TunnelStructureAttributeType">
    <xs:sequence>
      <xs:element name="tunnelType" minOccurs="0" type="gml:CodeType"/>
      <xs:element name="tunnelSubtype" minOccurs="0" type="gml:CodeType"/>
      <xs:element name="mouthType" maxOccurs="unbounded" minOccurs="0" type="gml:CodeType"/>
      <xs:element name="length" minOccurs="0" type="gml:LengthType"/>
      <xs:element name="width" minOccurs="0" type="gml:LengthType"/>
      <xs:element name="area" minOccurs="0" type="gml:MeasureType"/>
      <xs:element name="innerHeight" minOccurs="0" type="gml:LengthType"/>
      <xs:element name="effectiveHeight" minOccurs="0" type="gml:LengthType"/>
      <xs:element name="slopeType" minOccurs="0" type="gml:CodeType"/>
    </xs:sequence>
  </xs:complexType>