From the Apple Maps web site:

Apple is driving vehicles around the world to collect data which will be used to improve Apple Maps. Some of this data will be published in future Apple Maps updates.

We are committed to protecting your privacy while collecting this data. For example, we will blur faces and license plates on collected images prior to publication. If you have comments or questions about this process, please contact us.

See below for where we’re driving our vehicles next.

Interesting. [HT to Joe Caiati]