CUSTOMS officers are stepping up inspections to curb car smuggling at the three land border crossings. They fear recent crackdowns on smuggling by sea could force criminals to change tactics. The department's divisional commander, Assistant Superintendent Pang Kui-sum, said: ''We monitor this trend very closely and have progressively increased our inspections at the crossings.'' He said that this year officers had recovered 10 stolen luxury cars, including nine Mercedes-Benz and one BMW worth a total of $14 million, at the checkpoints at Lok Ma Chau and Man Kam To. No cases of car smuggling were discovered at the crossings last year. Every day, customs officers deal with about 21,000 vehicles at the three border checkpoints, which also include Sha Tau Tok. On Saturday they arrested a 41-year-old Hong Kong driver at Lok Ma Chau and seized three stolen luxury cars. The Mercedes, valued at $5 million, were found hidden behind boxes. They were reported missing from Happy Valley, Central and Castle Peak. The case has been handed to the Organised Crime and Triad Bureau for investigation. The driver was still being held last night and will appear in Fanling Court in December.