Aging thread but...
Normally we would use vehicle detection loops and loop controllers (that provide dry contact output(s) for detect / non) vs. photo eyes but the control is the same.
An entrance / gate will actually require THREE loops (or PEs) to count correctly. When the car pulls up to the gate to enter, it should cover TWO loops. This way, if the car decides to back-out, we can tell by the order of detection falling out whether it goes forward (and crosses the gate's loop) or back out.
20+ years ago, you could do this (back out after pulling a ticket) and give the ticket to a buddy that had been on the lot for a week and he could use it to get out under the grace period (varies by lot as needed) without paying.
NOW; the ticket generated at the spitter (I know that's not a part of this but..) will have a flag set in it's related database if the car backs out. This identifies that the ticket may be in use for fraud; especially if someone uses it to try and get out. Most places will call it an "alarm ticket".
This has also led many larger facilities to do "LPI" every night. That's license plate inventory. This is usually done with a handheld that has the lot's parking order laid out in a framework, so that each plate can be entered (just that data / space data is established) each night. If a customer tries to pass off an alarm ticket, it is seen at the exit and then the car will looked up on LPI to see it's real time spent on the lot. You actually can be charged a bit more as well, as most lots will bill hourly up to a daily max. The LPI is done at night, so they will bill it as full days at both ends.
To add to this... all entrances and exits SHOULD have at least two loops. That way, unintended entries and exits will still increment or decrement the lot count in order to maintain integrity. Decades ago, just out of college, I had a large deck at an airport that consistently "lost count". Video revealed cars driving up the center exit ramp the WRONG WAY (!!) We needed extra loops here (used singles on that exit ramp coming off of each floor) and then we were able to maintain counts/floor.
People do crazy things when they are driving in "unfamiliar" places, and they also seem to have very few scruples over trying to "steal time" that they actually spent on the lot.
Normally we would use vehicle detection loops and loop controllers (that provide dry contact output(s) for detect / non) vs. photo eyes but the control is the same.
An entrance / gate will actually require THREE loops (or PEs) to count correctly. When the car pulls up to the gate to enter, it should cover TWO loops. This way, if the car decides to back-out, we can tell by the order of detection falling out whether it goes forward (and crosses the gate's loop) or back out.
20+ years ago, you could do this (back out after pulling a ticket) and give the ticket to a buddy that had been on the lot for a week and he could use it to get out under the grace period (varies by lot as needed) without paying.
NOW; the ticket generated at the spitter (I know that's not a part of this but..) will have a flag set in it's related database if the car backs out. This identifies that the ticket may be in use for fraud; especially if someone uses it to try and get out. Most places will call it an "alarm ticket".
This has also led many larger facilities to do "LPI" every night. That's license plate inventory. This is usually done with a handheld that has the lot's parking order laid out in a framework, so that each plate can be entered (just that data / space data is established) each night. If a customer tries to pass off an alarm ticket, it is seen at the exit and then the car will looked up on LPI to see it's real time spent on the lot. You actually can be charged a bit more as well, as most lots will bill hourly up to a daily max. The LPI is done at night, so they will bill it as full days at both ends.
To add to this... all entrances and exits SHOULD have at least two loops. That way, unintended entries and exits will still increment or decrement the lot count in order to maintain integrity. Decades ago, just out of college, I had a large deck at an airport that consistently "lost count". Video revealed cars driving up the center exit ramp the WRONG WAY (!!) We needed extra loops here (used singles on that exit ramp coming off of each floor) and then we were able to maintain counts/floor.
People do crazy things when they are driving in "unfamiliar" places, and they also seem to have very few scruples over trying to "steal time" that they actually spent on the lot.
