In August, federal safety regulators outlined minimum requirements for "black boxes" in vehicles, but stopped short of mandating them, Detroit News reports.

The National Highway Traffic Safety Administration (NHTSA) issued a new rule to take effect in September 2010 that says the devices, officially known as "event data recorders," must be made more durable, that all automakers must collect the same type of data from them and must notify consumers in owners’ manuals if their vehicles are equipped with the devices.

NHTSA said the rule will enhance the value of automatic crash notification systems, including an enhanced 911 emergency response system under development, by making it easier for vehicles equipped with rapid crash notification features to provide information to emergency personnel.

NHTSA said 64 percent of all 2005 vehicles had event data recorders, but that number has risen significantly. Unlike airplane black boxes, black boxes in cars don't record voices. They typically record the short period before an air bag deploys and then the crash itself. Without a crash being severe enough to prompt an air bag deployment, no data is recorded, according to Detroit News.

Five states have adopted disclosure regulations to clarify when law enforcement may retrieve data. States are split on whether police need to obtain a warrant to get the data. Some privacy advocates have voiced concern about the data falling into the wrong hands or about "spying" on drivers.

Cars can also be tracked through E-ZPass or other automatic toll payment systems. A Connecticut rental car agency used GPS devices to monitor customers' driving habits and fined them if they sped. Mindful of the concern of some drivers, some states are considering banning the practice.

On July 1, a new law took effect in New Hampshire that prohibits state "surveillance" of vehicles "through the use of a camera or other imaging device or any other device, including but not limited to a transponder, cellular telephone, global positioning satellite, or radio frequency identification device."