46.2-1078.1 prohibits the use of handheld personal communications devices in certain motor vehicles under certain circumstances. Many uses of cell phones while driving are not prohibited by this statute.
The statute outlaws persons who are 1) operating a motor vehicle on public road in Virginia and 2) using a "handheld personal communication device" to: either A) "Manually enter multiple letters or text in the device as a means of communicating with another person" or B) "Read any email or text message transmitted to
the device or stored within the device," unless you are reading a name or number stored in the phone, or are using caller ID.
There are a number of additional exceptions. Persons operating the vehicle was "engaged in the performance of his official duties" and operators whose vehicles are lawfully parked or stopped are exempted. Notably, using a "factory-installed" or aftermarket GPS is exempted from the statute. The use of the device to report emergencies is also lawful.
A first offense is punishable by a $125 fine and a second offense is a $250 fine. Violation of the statute alone is not a criminal offense, but it is not uncommon to be charged with reckless driving where part of the conduct by the defendant involved the use of a cell phone. Reckless driving is a crime.
It will be difficult for an officer to show that you were using the device for one of the prohibited uses and not for one of the many exceptions, unless of course you told him what you were using the device for. The burden is on the government to prove beyond a reasonable doubt that you were using the device for one of the prohibited uses. Therefore, if you didn't tell the officer what you were using the device for, it is unlikely they will be able to prove their case.