One of the most important rites of passage for teenagers--obtaining a driver's license--will become more difficult in Maryland as new limitations on first-time drivers take effect today.

The regulations governing driver's licenses are among hundreds of new laws that take effect in Maryland and Virginia today. Cigarettes, for instance, now will cost more in Maryland. Virginia residents will receive the protections of a new "Patient's Bill of Rights" in dealing with health insurance companies. And both states will begin preparing consumers for the day when they can choose their own utility providers.

New drivers in Maryland--those who have just turned 16 and older people who have never driven--now will have to use more restrictive learner's permits for four months instead of the previous two weeks. After that, teenagers will receive 18-month provisional licenses that can be revoked for offenses that ordinarily might warrant just a ticket. They will not qualify for unrestricted licenses until they turn at least 17 and seven months.

The changes are the result of legislation passed last year as Maryland joined a national movement to toughen laws for teenage drivers in a bid to boost safety on the road.

In recent months, parents and teenagers throughout Maryland have been badgering driving schools for information and signing up for classes to try to beat today's change in the law.

"When they call us, the first question is the new law," said Dan Jimenez, manager of Montgomery Driving School in Rockville. He estimated that his spring enrollment was as much as 20 percent higher in large part because of the changes.

The earliest age that a young driver can get a learner's permit remains 15 years and 9 months, which means those youths can receive a provisional license when they turn 16 and 1 month. That's because a new law requires all first-time drivers, regardless of age, to have a learner's permit for four months. Previously, after turning 16, a person had to have a learner's permit for only two weeks.

The new law extends the minimum time that new drivers must have a more restricted "provisional license" from one year to 18 months. All Maryland drivers under 18 are forbidden to drive between midnight and 5 a.m. Neither Virginia nor the District imposes such a curfew.

The law also establishes a requirement that drivers with a learner's permit log at least 40 hours of practice time with an adult. And there are harsher penalties for new drivers who commit infractions while driving under their provisional license.

Moving violations, including driving without a seat belt, force new drivers to begin their 18-month provisional period over and take a driver improvement course. Second and third infractions can lead to suspension or revocation of licenses. Last year, Virginia passed similar harsher penalties for drivers under 18, but it did not include driving without a seat belt.

Maryland lawmakers passed the law after hearing statistics from safety experts who said that people ages 15 to 20 make up about 7 percent of the nation's drivers but account for 15 percent of all traffic fatalities.

"We don't think this is the be-all and end-all," said Richard M. Scher, spokesman for the Maryland Motor Vehicle Administration. "But we have seen enough accidents over the years that could have been avoided if the drivers had been more confident and competent behind the wheel."

Maryland lawmakers also targeted teenagers for another health reason this year, voting to increase the tax on a pack of cigarettes from 36 cents to 66 cents. Gov. Parris N. Glendening (D) had pushed for a $1-a-pack increase, arguing that the increased cost would drive down the number of young people who smoke. A reluctant legislature, however, approved only a 30-cent increase.

The electrical utility industries in Maryland and Virginia begin to deregulate as of today. In Maryland, mandated rate reductions of 3 percent to 7.5 percent scheduled to last four years won't kick in for another year for consumers. But power companies already have begun a media blitz in anticipation of the day when customers can choose their own utility much as they do phone service now.

As in Maryland, dozens of Virginia laws take effect today, from major reforms in health insurance to obscure measures that include a prohibition on the sale of bear meat and cash bounties on the ever-growing coyote population.

Most important of the health measures is a "Patient's Bill of Rights," which gives people easier access to medical specialists and encourages health maintenance organizations to cover experimental drugs for dangerously ill patients.

In education, the governing bodies of state colleges and universities will now be directed to reduce tuition and mandatory fees by 20 percent in the coming academic year, though several of those institutions appear ready to circumvent that directive by raising a series of non-academic fees.

A tougher Freedom of Information Act takes effect, clarifying requirements on public officials to release records to the public. And there are nearly 30 new categories of license plates, including one celebrating the history of Fairfax County and another commemorating the 300th anniversary of the City of Falls Church.

There will also be other plates for groups as diverse as the Sons of Confederate Veterans, Eagle Scouts and one marked for the Internet Commerce Industry, which may appeal to Northern Virginians working in that field.