We are giving up on exclusive fullscreen mode in Streetdeck with the next patch. This will mean windows dialogs can be shown over streetdeck and should fix the lockup issues.
The volume module will be safe while driving. There is already an EQ under the music settings, it will remain locked while driving.
A high contrast map view as well as gamma control have been implemented, they will probably make it in the next patch.
The DigitalMods are still a work in progress and wont' be released until the SDK is finalized. They default to being unsafe, but can be written to use while driving, it just hasn't happened yet though.