Starting last month, New York City began tracking about 400 people's driving habits, including how much gas they use, when they drive, where they are, and how fast their cars go. The program, called "Drive Smart," promises drivers discounts of up to 30 percent on their Allstate auto insurance, as well as "incentive rewards valued at $25," according to the program website.

The pilot program runs a year — until August 2016 — using a device that plugs into a car's on-board diagnostic port, or OBD-II, which is standard in any vehicle made after 1996. The device transits data directly both to the driver's smartphone and also to the Drive Smart cloud server. The program doesn't yet support hybrid or electric vehicles.

Some privacy advocates have warned about the possibility the device can be compromised. "Anything is hackable as we’ve already seen," security expert Manny Gomez told CBS New York. "Sony was hacked; the US government was hacked, so clearly the City of New York could be hacked and this information could easily become public."