While travelling at approximately 25 km/h on a single lane asphalt road, a vehicle approached and overtook me with an approximate speed differential of 5 km/h. When the vehicle passed me there was approximately 1m separation distance; the road was fairly close to straight, with no appreciable curves and being in the country there were no buildings, fences, towers, power lines, or telephone lines to interfere.
The vehicle was not detected at all and the vehicle was a recently manufactured Renault duster.
I was using the RTL+RDU, and at no stage did the RDU indicate the presence of the vehicle.
This was using v3.00 of the firmware, which claims: "Improved detection of slow moving vehicles and reduced false detections".