Automatic Vehicle Identification Methods

In Features by Raymond Jackson

Speed, security, efficiency, and ease of access are all fundamental components of a gated system. If you reflect on how long it takes to get into your average gated community or access-controlled parking garage, you spend a lot of time waiting to trigger the gate. For locations that see a lot of traffic, automatic vehicle identification (AVI) can prevent traffic jams and potential vulnerabilities at the gate.

RFID is emerging as one of the best solutions to this problem.

RFID tags, stickers, and badges have long been used in commercial settings. They have been recently scoring attention as a method for automatic vehicular identification in parking and residential settings. Whether you need to control the security of a residential complex, parking lot, or parking garage, RFID is the technology you’ll want running the show.

Access Management

RFID systems are easy simple to manage. As opposed to having a remote device or passcode system, an RFID tag uniquely identifies its holder. Tags can also be deactivated within the access control software, or set to automatically expire after a certain time. It all gives you more control over who goes in and out.

Property managers will especially appreciate being able to remotely deactivate credentials without hunting users down to get back their gate clickers.

Set automatic expiration times, mark tags as lost or stolen to immediately deactivate them, and more.

Set automatic expiration times, mark tags as lost or stolen to immediately deactivate them, and more.

Unique Identification

Legacy clicker systems have a major inherent vulnerability. Clicker signals can be easily duplicated or cloned using common, readily available technology. This allows a malicious party to gain unauthorized access, with no ability to track or recognize suspicious activity. RF theft is a much more difficult process easily foiled by signal encryption. Uniquely identifying codes work with your access control software to permit valid users and stop bad guys from getting in without a trace.


Common RFID solutions as used for personnel are transferable – think a keyfob, keycard, employee badge, etc. The problem with these is that they are easy to share or transfer from a valid user to an unauthorized individual. With or without the valid user’s knowledge. Even if a valid user wants to share his or her access, that means you have some sort of guest protocol which is being ignored or bypassed. Probably for a reason. Access sharing is a bad thing, no doubt about it.

In locations that value their security and protocols, transferable credentials like hang tags are not viable for this reason.

As a security measure, externally mounted vehicular RFID tags need to be non-transferable. Upon removal, the transmitter should break, rendering the tag useless for gaining access.

Accuracy is Key

It cannot be understated how important security access accuracy is, otherwise the whole system is useless. When searching for an automatic vehicular identification system on the market, you will notice three major categories: license plate recognition, windshield RFID, and, well, HeadlightStickers.

The most obvious shortcoming of the three comes from license plate recognition (LPR) systems. Trailer hitches, inclement weather, bad sun glare, and etc. can prevent license plate recognition systems from getting a clear positive identification. Because LPR has to deal with such conditions, most LPR systems have an “acceptable” margin of error to speed things up: something like five or six out of seven characters matched can give an access granted. Not acceptable.

License plate recognition is a great security feature, but it has many shortcomings as an access control system.

License plate recognition is a great security feature, but it has many shortcomings as an access control system.

The remaining RFID alternatives break down as follows:

Windshield-Mounted RFID Tags

Probably the most commonly used vehicular RFID solution. This requires a high mounted, conspicuous antenna at the driver’s lane.
Far more problematic is that windshields are often made with a metal oxide, which helps reflect the glare coming from the sun. This metallization can interfere with or entirely block the signal from transmitting.

Lastly, there are battery-powered windshield transponders, which do improve the signal strength enough to pass most metallized windshields. But you’ll pay a premium for those, both upfront and for the life of the transponder via battery replacements.

Headlight RFID Transponders

Lastly, we have headlight RFID. This does all of what windshield RFID stickers can do, without the big obvious barrier of a potentially metallized windshield to contend with. They require no battery, and are passively activated by the signal coming from the antenna. The reader then retrieves the unique ID from the sticker, and grants or denies access.

As an added bonus, you gain 6-7 feet of read range just by virtue of headlights being that much further ahead of the windshield mount point.

Instead of mounting the antenna up high to communicate with windshield stickers, you can now set the antenna down low, at headlight height (as low as 30 inches) for great results. This speeds up installation times significantly – you can flange mount the pole into the sidewalk instead of drilling a deeper hole and doing concrete work to accommodate a six or eight foot pole. And finally, low mounted readers just look better. Aesthetics matter to you and your end users.

If it seems like an obvious choice after reading the technology breakdown, well, that’s because it is.

Don't Use Clickers, Use HeadlightStickers!™Get a quote from a certified HeadlightSticker dealer!

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