The financial shock of adding a teenager to a family auto insurance policy is getting less shocking — at least somewhat.

An annual analysis by insuranceQuotes.com, a rate comparison site, found that adding a teenager still increased annual premiums substantially, but the magnitude of the increase has been falling over the past few years.

Adding a single teenager to a policy caused annual premiums to increase an average of 78 percent, or $671. But rate increases have been decreasing since 2013, when the average increase was 85 percent.

Laura Adams, senior insurance analyst with insuranceQuotes, said that factors in the trend may include safer automobile technology, a dip in the number of teenagers getting driver’s licenses and the continued impact of “graduated” driving programs, which place restrictions on new drivers until they gain more experience on the road.

But the impact of adding teenagers to a policy is still a jolt to families, especially those adding boys. Putting a male teenager on your insurance policy increased rates an average of 89 percent, compared with 66 percent for a female teenager, the analysis found.

Ms. Adams said premiums increased when a teenager was added because, statistically, younger drivers — particularly boys — have more accidents than older, more experienced drivers, and file more insurance claims.

Nearly 1,900 drivers aged 15 to 20 died in car crashes in 2015, according to the National Highway Traffic Safety Administration, up 9 percent from 2014.

Motor vehicle crashes are the leading cause of death among teenagers, according to the Centers for Disease Control and Prevention.

As with most insurance costs, the impact of adding a teenager varies by state. Adding a teenager in Rhode Island bumps up premiums by more than 150 percent, while parents in Hawaii get about an 8 percent increase.

For the analysis, insuranceQuotes.com hired Quadrant Information Services, an insurance data firm, to calculate the price increase of adding a driver aged 16 to 19 to a family’s auto insurance policy. The averages are based on a hypothetical couple — a man and a woman, both 45 years old, married and employed — who each drive 12,000 miles each year and have good credit and driving records. The policy tested included $100,000 for injury liability, $300,000 for all injuries, a $500 deductible on collision and comprehensive coverage, and uninsured motorist coverage.

Here are some questions and answers about teenagers and auto insurance:

How can I reduce the cost of having a teenage driver on my policy?

Kathy Bernstein Harris, senior manager for teenage driving initiatives at the National Safety Council, a nonprofit, said that some insurers offered discounts for students who get good grades (even though it’s not necessarily clear that being a good student correlates with safer driving). Discounts are also often available for new drivers who take driver’s education classes.

Ms. Harris said the best way to reduce claims and hold costs down — and keep your child safe — was to set rules and spend time driving with teenagers and coaching them along, even after they pass their driver’s license tests. “Just getting a piece of plastic doesn’t mean they are totally prepared for the open road,” she said. “The first year of independent driving is the riskiest.”

Many state programs set restrictions on teenage drivers, such as curfews for night driving and limiting the number of other people, particularly other teenagers, who can ride in the car with them. Ms. Harris urges parents to follow such rules. “With every teen passenger you put in the car,” she said, the risk of a crash increases.

The council’s DriveitHome website offers resources for parents and teenage drivers, including interactive safety tests.

Are some cars safer than others for teenagers to drive?

The Insurance Institute for Highway Safety each year publishes a list of safe, affordable cars for teenagers. In general, larger, heavier vehicles are best.

Ms. Harris suggests that parents not buy a new car specifically for their new teenage driver — or, if they do, that they make it clear that the car is the family’s car, rather than the teenage driver’s personal vehicle. By making the car a “family” car, she said, parents can better set rules for its use and talk about where their child is headed and who is expected to go along.

Also, she advises getting teenagers involved in researching the safety and price of a new car, as a way of teaching them lessons about budgeting, and emphasizing the need for safe driving habits.

Are there apps that can help reduce distracted driving?

Technology is emerging that can disable texting and social media on cellphones while the car is in motion. One system, Cellcontrol, recently was favorably reviewed by Consumer Reports.

The organization also offers other tips for reducing distracted driving and increasing safety for teenage drivers on its website.

Credited to The New York Times