A state Senate committee was scheduled to consider a bill Tuesday that would penalize drivers for failing to show proof of insurance when registering or re-registering their vehicles. The bill also would allow police to impound vehicles whose owners can't prove they're insured.

The issue shows the depth of concern in California over uninsured motorists, who are estimated to represent between 25 percent and 28 percent of the state's 20.1 million licensed drivers.Proponents of tougher measures to force compliance with the state's existing financial responsibility rules say that uninsured motorists and their higher accident rates cost legal drivers between $1 billion and $2.3 billion each year.

They contend that the state's means of enforcing the law are inadequate. The Department of Motor Vehicles is not equipped to check for insurance and police are not allowed to check for active policies when making routine traffic stops, proponents of the measure argue.

They propose to enforce the laws by requiring proof of insurance with all applications to register, renew or transfer a vehicle registration. The proposed law, A.B. 650, would also require drivers to furnish proof of

financial responsibility - which can be a bond, insurance policy, cash deposit or DMV-approved self-insurance - when asked to do so by a law-enforcement officer.

If the driver can't furnish such proof, the law would authorize the vehicle to be impounded until proof of financial responsibility is demonstrated. Knowingly providing false evidence of financial responsibility would be punishable as a misdemeanor.

The measure is opposed by the California insurance industry, which is pushing for comprehensive reform that would make insurance affordable to the thousands of people who currently drive without it.

Without affordable coverage, industry officials say, low-income drivers will continue to drive without insurance and will falsify coverage or ignore registration requirements altogether.

''Low-cost auto reform requires all drivers to purchase the basic policy which, by definition, satisfies the state's minimum financial responsibility laws," Lynnea Olsen, vice president of the Association of California Insurance Companies, wrote in a July 7 letter to Sen. Quentin Kopp, chairman of the Senate Transportation Committee. The committee was scheduled to consider the measure on Tuesday. A similar bill has passed the state Assembly.

Supporters of the bill include the California Trucking Association, which says that a similar standard already is applied to the state's trucking industry and should be applied universally.

''We support this (bill) because it is already the way business is done in the trucking industry," said Jay Van Rein, a CTA spokesman.

The insurance association says the bill leaves certain issues vague, including the requirement for an owner to reclaim a vehicle that has been impounded under the law.