Travelling from Vilnius or Alytus (Lithuania) via Warsaw (Poland) to Rotterdam (Netherlands) quite frequently, it appears that the 'fastest route' sends you via White Russia (Belarus). Indeed it is some 25 km's shorter than via the Lithuanian/Polish border crossing at Lazdijai (Lithuania). But two (!) hours consuming border crossings between Lithuania and White Russia and later between White Russia and Poland will never provide you the 'fastest route'.
Would be challenging to implement those non EU border procedures into the estimated travelling time in order to supply the actual 'fastest route'.