Set the display status of the Toolbar for the front side of your website (you cannot turn off the toolbar on the WordPress dashboard).
<?php show_admin_bar( $bool ); ?>
This function can be called immediately upon plugin load or placed in the theme's functions.php file.
This function will also affect the display of the Toolbar in the dashboard for WordPress versions prior to Version 3.3.
show_admin_bar( false );
Placing the above line of code in theme's function.php file will prevent the Toolbar from rendering on the front end of your site.
show_admin_bar() is located in