47 CFR 90.269 - Use of frequencies for self-powered vehicle detectors.
(a) Frequencies subject to § 90.20(d)(22) may be used for the operation of self-powered vehicle detectors by licensees of base/ mobile stations in the Public Safety Pool in accordance with the following conditions:
(1) All stations are limited to 100 milliwatts carrier power and 20K00F7W, 20K00F7X, 20K00F8W, 20K00F8X, 20K00F9W or 20K00F9X emissions. The frequency deviation shall not exceed 5 kHz. No more than two 30 ms. pulses may be emitted for each vehicle sensed.
(2) The transmitters must be crystal controlled with a frequency tolerance of plus or minus .005% from −20° to plus 50 °C. They must be certificated.
(3) The total length of the transmission line plus antenna may not exceed one-half wavelength and must be integral with the unit.
(4) All operation shall be on a secondary, non-interference basis.