Since cyclists are required to stop at signals, it therefore follows that the city council highways department are required to ensure that the sensor(s) is/are sufficiently sensitive to detect the presence of one bicycle.

If the system cannot do this, you should badger your local councillor to insist that they do this.

If your memory is, indeed, correct and you have to wait for a, what, a sensor (new collective noun) of cyclists to arrive, then the regulations are barking