You can personalise your account by linking it to your Facebook account. In that case you will be able to select one of the avatars offered by Facebook.

If you would like to change your Facebook provided avatar, follow these steps:
- open your Facebook account Settings
- go to 'Apps and Websites' settings
- find Traffic Puzzle among apps and websites you've linked to your Facebook and press 'View and Edit'
- on the editing page you can select a new in-game avatar from those offered by Facebook.