Florida will become the first state in the nation to deregulate its trucking industry completely on Tuesday.

The Florida truck regulatory code was to expire automatically at midnight tonight under a "sunset" provision. Efforts by the legislature to pass an amended truck regulation code were deadlocked when the session ended June 11.

Some trucking executives claim chaos will follow deregulation. Just before the law expired, lawyers filed suits against the state on behalf of at least 19 trucking firms. They want a declaratory judgment from the state court holding that it is unconstitutional to let the regulation expire.

The truckers say it will deprive them of long-held property rights in their certificates to do business issued by the Florida Public Service Commission, which formerly regulated trucking.

But members of the PSC aren't so sure chaos will ensue.

Billy Mayo, a senior member of the commission, said "I don't really and truly think anybody can say they know what's going to happen, because this situation just hasn't existed now for about 40 or 50 years."

Mayo said he thinks the immediate result may be that some truck routes to small towns will be abandoned and some trucking freight rates will go down. He said small independent truckers probably will begin to provide service to most of the small, out-of-the way towns which the big truck lines abandoned.

Many small independent truckers, unable to get a certificate of public convenience from the PSC, worked as subcontractors for the bigger, certified firms. Now they will be free to haul freight on their own. Typically they paid the bigger firms 18 percent of their gross income for the use of their certificates.