Customs Relevance Check 
To determine whether a business document is relevant for a customs process (for example, export or transit), the system runs the customs relevance check that is assigned to the customs activity. The customs relevance check determines, for example, whether goods are to be transported into a country that is in a different customs union and an export declaration is therefore required.
The following are examples of the available standard customs relevance checks:
EXP_EU
This check is used for export processes in freight documents (see Export Declarations by Shippers).
It checks whether the source and destination countries belong to the European Union. The goods are customs-relevant if the destination country is different from the source country, that is, one of the countries is not in the European Union. The relevance check identifies whether a country belongs to the European Union by checking the relevant setting in Customizing for SAP NetWeaver under .
Note that if you are transporting goods between two countries outside the European Union, the EXP_EU check cannot identify whether the countries belong to different customs unions. If you want to check customs relevance in this case, you can implement the Business Add-In (BAdI) BAdI: Change Result of Customs Relevance Check. For more information, see Customizing for Transportation Management under .
TRA_T1
This check is used for opening the transit procedure in a freight document (see Transit Procedure for Freight Documents).
It checks the following:
Automatic customs handling has been specified for the corresponding forwarding order in Customizing for the forwarding order type.
The transit procedure has been selected as the inbound customs activity for at least one of the items.
The transit procedure has been specified for at least one stage in the actual route.
There is at least one item without a movement reference number.
If these requirements are met, the freight document is relevant for the transit procedure.
For information about all standard customs relevance checks, see the documentation of the Customizing activity Define Customs Relevance Check.
You make the following settings in Customizing for Transportation Management under :
You define customs relevance checks in the Customizing activity Define Customs Relevance Check.
You assign customs relevance checks to customs activities in the Customizing activity Define Customs Activities and Profiles.