Parking Spotter

Sacramento County's mobile license plate recognition system locates scofflaws, eyeballs vehicles that overstay their welcome and helps recover stolen cars.

by / June 27, 2005

Parking enforcement can be a labor-intensive job.

Officers read meters, chalk tires and return to see if the cars moved, scrutinize permit stickers, and drive around looking for vehicles whose owners haven't paid their parking fines.

Sacramento, Calif., is one of the latest cities to streamline these parking enforcement activities with help from license plate recognition (LPR) software, mobile computing and GPS technologies.

Since July 2004, the city has piloted AutoFind, a mobile LPR system from Montreal-based AutoVu Technologies.

In 2004, the city Department of Transportation's (DOT) Parking Services Division installed an AutoFind unit on one of the three-wheeled scooters officers drive when checking for illegally parked cars. It also installed one on its boot truck, which is used to hunt down vehicles with five or more unpaid parking tickets and install boots on their wheels. The city equipped a second scooter this spring and may eventually add more to its 30-scooter fleet.

"We're going to keep adding to the extent that it makes sense to do so," said Howard Chan, the DOT's parking services manager.

AutoFind's onboard equipment includes four digital cameras, a GPS receiver and a mobile computer with touchscreen interface. As the enforcement vehicle drives by, two cameras, mounted on the vehicle's roof and pointed to the right and left, capture images of license plates on parked cars. The system stores these images and uses optical character recognition to translate the numbers into machine-readable characters.

The system also notes when and where it acquires each image. Two other cameras, mounted on the rear of the vehicle, photograph the tires of parked cars.

No More Chalk
In Sacramento's parking enforcement application, an officer drives a scooter through a designated area -- perhaps 10 or 12 blocks in a two-hour parking zone -- capturing vehicle images and data. "We've automated the process of chalking tires," Chan said. Two hours later, the officer drives the same route. The system compares the license plate numbers and geographical positions to the list acquired on the previous drive.

"If there's a match with someone who's stayed there more than two hours, there's an audible beep," Chan said. "Then we're notified that the vehicle's in violation." The enforcement officer loads a picture of the plate onscreen and does a visual check to verify that it's the same vehicle. "If it is, we issue the citation," Chan said.

Along with the license plate image, the screen can display the vehicle's position on a digital map, so the officer can compare its locations at time one and time two, said Tom Keeley, AutoVu's vice president of sales and marketing. The officer can also view pictures of the tires, and if the valve stems are in the same position in both pictures, that's further proof the car hasn't moved.

The DOT installed AutoFind on its boot truck to help find more parking scofflaws. In the past, two officers patrolled the city, carrying a printout with the license plate numbers of hundreds, even thousands, of drivers with five or more unpaid parking fines. To compare vehicles on the street with vehicles on the list, they had nothing but their eyes.

Now the DOT downloads a current database of repeat offenders into the AutoFind unit each morning. When the system locates a plate number that's on the list, it alerts the officer, who verifies the car's identity, and if appropriate, installs a boot.

The technology made a dramatic difference in the boot program, Chan said, noting that in fiscal 2004, before the city implemented AutoFind, the DOT booted 227 vehicles, while in the first nine months of fiscal 2005, through March, the city booted 612 vehicles.

"If we project that out to the end of the year, we're going to do over 800 by the

end of fiscal 2005," he predicted.

Because it helps the city collect more parking fines, the boot application alone has already more than repaid the $150,000 invested in the first two AutoFind units, Chan said.

Sacramento also uses a parking permits database to help officers determine if vehicles are legally parked in certain residential areas. Before, officers patrolling on scooters examined permit stickers visually. Now AutoFind compares the plate it reads to plate numbers in the database.

"Unless the scooter beeps when we drive by, we don't stop," Chan said.

It's harder to quantify the benefits the department has gained from the parking enforcement applications than from the scofflaw application, but AutoFind has helped boost efficiency, Chan said.

"We can patrol a larger area with the same number of officers, or spot more violations in a small, high-traffic area."

Other Uses
This year, the city also started loading a database of stolen vehicles reported throughout California into the AutoFind computer. If the system reads a plate that matches a record in this database, the DOT notifies the Sacramento Police Department. As of early April, police used these reports to recover two stolen cars, Chan said.

Nearly all AutoFind customers upload data to and extract data from the onboard computers via a Wi-Fi local area network. "Sacramento is our only client currently not doing that," Keeley said. "We're just using a jump drive to transfer the data back and forth."

The DOT plans to go wireless eventually, using an access point in its garage to transfer data when an equipped vehicle drives in or out, Chan said.

At the back end of the AutoFind system, an application running on a desktop computer uses data pulled from the mobile computers to produce reports. Managers can learn how many plates were scanned per hour, how much time officers spent patrolling, how many violations they identified, how many apparent violations officers rejected and other facts about enforcement activity.

"The system also keeps a record of all the evidence generated by the system and certified by the officer," Keeley said, adding that the information can be printed out as needed for use at a hearing.

The department uses the management system to trace the routes its equipped vehicles drive, using data from the GPS receivers. This data helps the department fine-tune officer deployment, Chan said.

"If we notice a lot of crossover between officers in the course of the day, we might redefine a beat."

Automating Work
When it started testing AutoFind, the DOT also made a separate move to replace handwritten parking citations with tickets generated on handheld computers. Eventually the department might connect the two systems so when AutoFind detects a violation and the officer confirms it, the handheld will automatically issue a citation, Chan said.

Keeley said AutoVu is working with a handheld computer manufacturer, which he declined to name, to integrate ticket-printing capabilities directly into the onboard computers. "We'll have that available by early summer," he said.

AutoFind has been deployed in more than 30 North American cities, including Chicago and Salt Lake City. One of the first was Monterey, Calif., which has used a single unit to enforce parking regulations and find scofflaws since 2002.

For Monterey, the main incentive was to reduce on-the-job injuries. "We had quite a few workers' comp claims from chalking," said Wayne Dalton, administrative analyst for the city. "We were looking for a way we could do the routes with a light-duty person."

The investment paid off, Dalton said, noting that since implementation, the city hasn't had any workers' compensation claims filed related to tire chalking.

Merrill Douglas Contributing Writer
Platforms & Programs