Sweeping Up Parking Violators
By Simon Mihajlovic
License plate recognition technology is optimizing street-sweeping operations and helping cities catch even more scofflaws.
For most cities, providing municipal services that are both environmentally-friendly and cost-effective are at the top of the agenda. One service that merits particular attention is street sweeping. The use of street sweepers really benefits the environment by removing not only solid debris, but also pollutants such as oil, grease, nitrogen and phosphorus off the roadways.
However, the nemesis of every street sweeper is the illegally parked vehicle.
For every vehicle blocking the sweeper along its route, three parking spaces’ worth of street are kept from being cleaned. Over an entire route, this adds up quickly and causes a high volume of contaminants to be picked up by storm water runoff, making their way into waterways.
Despite the passing of bylaws to prohibit parking during sweeping operations, violators are not easily deterred and the streets are seldom clear of vehicles. To patrol all sweeper routes adequately, cities must resort to increasing the number of parking officers and associated resources, such as parking enforcement vehicles. Faced with compressed budgets, cities need more effective means of keeping the streets clear.
One option is the use of license plate recognition (LPR) technology. Through optical character recognition (OCR) on images taken by specialized cameras, this technology enables automated reading of vehicle license plates. When used on a street sweeper, the LPR solution will scan for and detect parking violators.
Law enforcement and various traffic applications have been leveraging LPR technology for several years, and LPR has proven to be an effective and reliable force-multiplier in the detection and verification of license plates. Today, LPR is becoming more widespread for parking enforcement applications, and it is even being deployed in cities across the U.S. in street-sweeper applications.
How does it work?
Specialized LPR cameras installed on the street sweepers automatically detect and capture images of illegally parked vehicles along their route, as they go around avoiding them. The cameras are very advanced and built for the harsh duty seen on street sweepers. They are capable of reading license plates with high accuracy, at full cruising speed, and in complete darkness as well.
Certain cameras even have built-in computers capable of doing all the LPR processing, translating to a very minimal hardware footprint inside the sweeper. The entire LPR system is designed for ease-of-use and for minimal involvement from the in-vehicle operator. Typically, the operator will need only to pause and resume the camera reading using a small touch-screen computer inside the sweeper cabin.
The LPR system can even be fully automated, automatically activating the cameras when the sweeper brushes are in the down position, for example.
All vehicle LPR captures are silently logged, and include the license plate number, time and location of violation, an image zoomed on the license plate, and a color overview picture for vehicle identification. It’s also possible to include an additional wide-angle shot of the surrounding area, so that the vehicle and parking sign appear in the same view, as some cities require the additional evidence in case of ticket disputes.
The captured records are then transferred to a back-office software application, where they are stored in a central database and made available, as necessary, for review. The transfer can be done with a bulk offload at the end of the sweeper’s shift or even in real-time should wireless connectivity be available.
A sweeper also can be configured to send captures to different offices depending on the zone they are currently sweeping. From that point on, processes are put in place so that back-office reviewers can verify the data, issue the ticket for mailing, and even upload it to a website so that the vehicle owner can view and pay his citation online.
More LPR with sweeping operations
Optionally, additional functionalities can be leveraged from deploying LPR systems on street sweepers. As systems are equipped with a GPS antenna, geo-localization data can be used to track the sweeper’s route. It can then be played back from the back-office software, allowing managers to extract metrics that could help them better manage their street-sweeping crews.
Another possible functionality of the LPR system is real-time hotlist matching. Collaborating with law enforcement agencies, cities can obtain lists of vehicles of interest (also known as hotlists), such as wanted felons, amber alerts and stolen vehicles.
These lists can then be loaded into the sweepers’ LPR systems so that every license plate captured is verified against these lists as a background process. In the event of a positive match, an alarm would silently be sent in real-time to a back-office system operator, or even directly to the responsible law enforcement agency.
Taking a look ahead
Moving forward, cities may be faced with challenges when rolling out LPR technology. On the legislative front, changes may be required to issue tickets by mail, rather than serving them on-site.
There also may be some questions on the validity of the images as evidence of the violation, but LPR systems have proven they can overcome these obstacles with their imaging quality, the precision of their geo-localization data, and the reliability of their chain of custody.
Cities also may face pressure on public privacy issues. However, LPR systems focus mainly on the vehicle and the license plate, and not on vehicle occupants. Furthermore, all non-citation data can be immediately discarded, excluding the “Big Brother” effect.
Overall, license plate recognition technology has proven itself to be an efficient productivity tool and is worth a look for any city with street-sweeping operations.
LPR technology will reduce costs associated with additional patrol staff needed to enforce the sweeper routes and will allow parking officers to focus on higher priority enforcement tasks.
It may also dramatically increase the number of violations detected and enforced, providing a very fast return on investment.
But at the end of the day, LPR technology brings something even more important to the table: empowering cities to be greener by keeping their streets clean and clear of pollutants.
Simon Mihajlovic, an LPR Specialist at Genetec, can be reached at firstname.lastname@example.org.
Article Abstract from February, 2011