The debts of two public corporations that operate major bridge and road systems are snowballing as traffic continues to fall far short of initial estimates, a government inspection report warned Tuesday.

The Honshu-Shikoku Bridge Authority, which operates three roads and bridges linking Honshu and Shikoku, is saddled with 4.37 trillion yen in debt, but has assets of only 3.53 trillion yen, the Management and Coordination Agency said. As of the end of March 1999, it had 837.7 billion yen in negative net worth.

Likewise, Japan Highway Public Corp., which operates the Aqualine expressway that runs beneath Tokyo Bay to connect Kawasaki and Kisarazu, Chiba, has been spending 316 yen to make 100 yen in revenue, the agency said. Traffic volume on the Aqualine is 31 percent of what the public corporation had estimated, the agency said.