Hunter Stuart, writing in the HuffPost »

“There’s not always much public information on the algorithms that the insurance companies use to create your score,” said Thorin Klosowski with the Electronic Frontier Foundation.

“We might know that a full start or a slam brake or a too-fast acceleration is a certain number, but we don’t always know how that affects your overall score,” Klosowski said. “It can be hard to suss out how individual behaviors like this actually affect you, other than just opting into the program and looking at how your premiums change or don’t change over the course of a certain number of months.”

Privacy experts also say insurance companies lack the full, real-world context required to know whether a driver is behaving safely or not in a given moment.

“It’s all based on probabilities,” said Helen Nissenbaum, a professor of information science at Cornell Tech who’s authored research on digital privacy, location tracking and similar topics. “The insurance companies are talking as if they can reliably infer safe driving from whatever the sensors in our phones happen to generate without consideration for context. In many cases, fast acceleration is a sign of a good driver. Needing to accelerate quickly to avoid getting rear-ended is exactly a case of that.”