The standard pneumatic tube counter counts bicycles with an inaccuracy of approximately five per cent. A drawback is that it is rather vulnerable to vandalism. Yet it is still being used quite often. In the Den Haag metropolitan area pneumatic tube counters will shortly be installed at 12 fixed locations,
The French company Eco Counter has lately sought the limelight with an inductive loop developed specifically for counting bicycles. The loop is installed several centimetres beneath the road surface, in a diamond shape. Thanks to sophisticated algorithms and in combination with some electronics the loops may distinguish between bicycles and cars. Several small-scale studies have been conducted with this type of loop, among other by French authorities. In a - albeit small - random test these found an inaccuracy of 5 per cent in mixed traffic.
In the Netherlands the province of Drenthe is testing the loops in two locations, one a separate bike path, the other a road with mixed traffic. A single recording device will alternate between both locations. The focus will be on whether the counters manage to correctly count individual cyclists in groups. First results appear to be positive. Final results of this experiment will be available in a few months.
Another technique that may be useful for the future is provided by Delft. There fibre-optic cables beneath the bike path are used to operate the counting post. On one side LED light is introduced into the cable, on the other side the light frequencies are measured. Due to the pressure of the bicycle wheels the fibre-optic cable is slightly deformed, thereby changing the reflection within the cable. As a result, the light frequencies measured change as well, and cyclists are detected. The results are still being studied in Delft.