Upon Mr. Dahl’s request, LexisNexis sent him a 258-page “consumer disclosure report,” which it must provide per the Fair Credit Reporting Act.

What it contained stunned him: more than 130 pages detailing each time he or his wife had driven the Bolt over the previous six months. It included the dates of 640 trips, their start and end times, the distance driven and an accounting of any speeding, hard braking or sharp accelerations. The only thing it didn’t have is where they had driven the car.

According to the report, the trip details had been provided by General Motors — the manufacturer of the Chevy Bolt. LexisNexis analyzed that driving data to create a risk score “for insurers to use as one factor of many to create more personalized insurance coverage,” according to a LexisNexis spokesman, Dean Carney. Eight insurance companies had requested information about Mr. Dahl from LexisNexis over the previous month.

“It felt like a betrayal,” Mr. Dahl said. “They’re taking information that I didn’t realize was going to be shared and screwing with our insurance.”

Automakers and data brokers that have partnered to collect detailed driving data from millions of Americans say they have drivers’ permission to do so. But the existence of these partnerships is nearly invisible to drivers, whose consent is obtained in fine print and murky privacy policies that few read.

Especially troubling is that some drivers with vehicles made by G.M. say they were tracked even when they did not turn on the feature — called OnStar Smart Driver — and that their insurance rates went up as a result.

“I don’t know the definition of hard brake. My passenger’s head isn’t hitting the dash,” he said. “Same with acceleration. I’m not peeling out. I’m not sure how the car defines that. I don’t feel I’m driving aggressively or dangerously.”

In response to questions from The New York Times, G.M. confirmed that it shares “select insights” about hard braking, hard accelerating, speeding over 80 miles an hour and drive time of Smart Driver enrollees with LexisNexis and another data broker that works with the insurance industry called Verisk.

Customers turn on Smart Driver, said Ms. Lucich, the G.M. spokeswoman, “at the time of purchase or through their vehicle mobile app.” It is possible that G.M. drivers who insisted they didn’t opt in were unknowingly signed up at the dealership, where salespeople can receive bonuses for successful enrollment of customers in OnStar services, including Smart Driver, according to a company manual.

After LexisNexis and Verisk get data from consumers’ cars, they sell information about how people are driving to insurance companies. To access it, the insurance companies must get consent from the drivers — say, when they go out shopping for car insurance and sign off on boilerplate language that gives insurance companies the right to pull third-party reports.

This summary contains 489 words. I'm neither a bot nor open source, but the bot summary was poo.

As usual, lack of transparency is of key concern. Digital opt-in where other people have physical control of the device and have a profit motivation should not be acceptable.

The quote about what is a hard brake exactly or heavy acceleration is most relevant to my thoughts. Without any context, are you hard braking to avoid dangers? How many hard brakes are acceptable? What is the penalty for hard braking, etc?

My girlfriend tried the OBD reader for her insurance for a bit, and it didn't anything one way or the other to her insurance. For something as random as driving, I dont see who would want to volunteer for it. We know the only direction prices ever move is up, so what does the consumer have to gain?