MANILA, Philippines — North Luzon Expressway (NLEX) Corporation warned motorists to expect heavy traffic in Bocaue, Bulacan as K-pop boy group Seventeen holds its world tour stop at the Philippine Sports Stadium on Saturday, March 21.The tollway operator said traffic buildup is expected in the venue area and along NLEX-covered roads leading to Ciudad de Victoria.NLEX Corporation advised concertgoers to take the Ciudad de Victoria exit and urged …