Why is hook_forms form callback not reached?
Instead of:

return $forms[$form_id] = array(
            'callback' =&gt; 'driver_route_form',
            'callback arguments' =&gt; array($form_id, $args),
        );


You should have:

$forms[$form_id] = array(
            'callback' =&gt; 'driver_route_form',
            'callback arguments' =&gt; array($form_id, $args),
        );
return $forms;