Carmaker are concerned that new legislation being drafted in the US Congress designed to improve vehicle safety could increase manufacturing costs and lead to more civil lawsuits.

The legislation, unveiled this week by Senate Commerce Committee Chairman John D. Rockefeller, is among several proposals that seeks to address issues raised by Toyota ’s recent recalls for sudden-acceleration problems.

A similar bill being written by Rockefeller’s House counterpart, Rep. Henry Waxman, is the subject of a hearing tomorrow.

The proposals would increase civil penalties imposed on companies found to have hidden or mishandled car defects, removing the current cap of US$16.4m. They would also make it harder for federal safety regulators to become industry lobbyists and would boost funding for the National Highway Traffic Safety Administration, the agency that investigates defects.

The bills would also impose new rules on car design, covering everything from pedal placement to the performance of electronic-throttle-control systems. Every car would be required to have so-called black boxes that record crash data and technology to ensure a car stops when the gas and brake pedals are simultaneously suppressed.

Michael Stanton, president of the Association of International Automobile Manufacturers, which represents Toyota, Honda and Nissan, said the industry wants to work with Congress on a bill but added that the proposals are too detailed in what the new technologies should achieve and would put pressure on federal regulators to implement the new rules too quickly.

Some new standards would apply to vehicles manufactured within two years after the legislation is passed, a timeline that automakers are calling unrealistic and highly costly given that vehicle lineups are planned years in advance.

Many vehicles are already equipped with event-data recorders and brake-override systems, but the new legislation could require more-advanced technology.

The Rockefeller and Waxman bills require that black boxes record data from 60 seconds before a crash, a broader time period than current devices typically record. Car companies say the new rules could add thousands of dollars to the cost of a vehicle.

They said they will argue for less prescriptive requirements and looser deadlines.