The sensors will need to be mounted so that the beam is about two feet above the roadway, which usually requires installing posts (or small cabinets) on each side of the lane or roadway. The largest problem with IR sensor installations is maintaining alignment, newly installed posts are prone to twisting or tipping as the ground settles and the sensors can go out of alignment, also, posts are subject to accidental or deliberate vandalism which can knock them out of alignment. The reflective type of sensors use a plastic retro-reflector on the opposite side of the gap from the sensor unit, which is highly visible, and as a result subject to increased vandalism. Both types of sensors need to keep the optics cleared of dust, the dust will cause gradual degradation of the signal until the unit finally fails. The reflector, due to it's relatively large size is most sensitive to dust buildup.

Both types of sensors would work well in toll booth installations for instance, where there are suitable mounting frames on both sides of each lane, the reflector type would be easier to install, since no wiring would need to run under (over) the road to the other side. If the sensor must sense across more than one lane, the transmissive type of sensor is the one to use. Transmissive sensors can be very effective as a method of vehicle detection on forest service roads, where other types of sensing schemes just won't work. To minimize dust problems in the dry seasons, the transmissive sensor could be mounted a long distance from the roadway, with suitable dust hoods over the optics.

DAI's counters will directly interface to the outputs of these sensors, and depending on the application, we can supply the IR sensors already pre-wired for a "plug and go" installation. We have supplied counters connected to IR sensors used in stores and at trailheads for pedestrian traffic counting, as well as for vehicle detection on roadways. If you have a specific need, we can probably tailor one of our counters to your application. Give us a call.