Features:
App detects cars to your left & right, cars stopped, cars going slowly.
If they're near enough, it displays text and plays an audio notification in the style of a spotter.
Installation:
Unzip into your steamapps/common/assettocorsa/ folder, select icon.
Configuration:
audio clips are in apps/python/Spotter/audio/ subfolders and if you add your own folder it will use the clips in there. Include audio.ini to define the specific wav files, or to include multiple clips for one event.
alternate audio is also available in the Assetto Corsa forum thread (see "Alternate Audio" section for multiple options)
text is in apps/python/Spotter/text/, by default it uses english1.txt but you can add others by writing your own messages on the same lines.
Also see Spotter.ini for configuration parameters that didn't make it into the UI (they're just in the 'display' section, the rest is on the UI)
Misc:
A lot of people are slow, you might want to turn that down from 60% to even lower.
Credits:
I wrote the bulk of the script.
Some of the audio code is thanks to Rombik.
Other audio code thanks to rafffel.
The included audio is by Wattie.