An iPhone camera isn't really good enough to OCR vehicles as you move past them in a parking lot. You get skew from rolling shutter effects, plus it's going to be shaking violently when attached to an automobile without proper dampening.
The cameras used for OCR on license plates need to have a fairly high resolution, fast shutter speed, and a number of other little additions which make it more expensive than an iPhone camera. Granted, $10,000 is really expensive for such a device, and the real cost for something like that is probably a few hundred dollars, but after you add in software and radio communication (probably a cell plan if I had to guess), you're looking at an expensive device.
Of course, we could build one ourselves for a fraction of that, but that's why we don't drive tow-trucks or license plate scanner cars for a living.
The cameras used for OCR on license plates need to have a fairly high resolution, fast shutter speed, and a number of other little additions which make it more expensive than an iPhone camera. Granted, $10,000 is really expensive for such a device, and the real cost for something like that is probably a few hundred dollars, but after you add in software and radio communication (probably a cell plan if I had to guess), you're looking at an expensive device.
Of course, we could build one ourselves for a fraction of that, but that's why we don't drive tow-trucks or license plate scanner cars for a living.