There is a way that you can make directional POI for and POI Corridors for speed cameras.
I have successfully done this using Extra POI Editor Version 5.32 by Turboccc. (using circles)
The Poi will only trigger when you are driving inside the circle (similar to Cyclops)
[Only registered and activated users can see links. ]
This is an Example of a POI using Circles using Turboccc EPE This POI Triggers in both directions.
If you only Draw the Circles on One side the POI then becomes directional.
We Also use the 30m system in South African SpeedCam POI (Implemented by Mr F. Viljoen).