While the sensors are designed to make it easier for city staff to monitor the parking system, big trucks rolling or cars parked nearby can trip the sensors, resetting the meters and falsely indicating the space was not paid up.
In-ground sensors intended to make parking downtown more efficient have been too-easily tripped since being installed last year, leaving some paying customers with tickets rather than minutes on their meters.
The sensors are supposed to wirelessly tell the meters on the sidewalk when a car is in the spot or not. The meter then resets accordingly.
But apparently those sensors may have been set a touch too sensitive, according to Matt Huffaker, assistant to the city manager.
A big truck rolling by or a car being parked nearby can trip the sensors, resetting the meters to zero and leaving a red light blinking, indicating the car in the space was not paid up.
This happened to one downtown parker, who did not wish to be named but confirmed she paid for parking on Bonanza Street and returned to find a ticket. She was able to call the city to verify the sensor malfunction and her ticket was cleared.
"If the settings are too sensitive they will pick up other metal objects ... and if too low, they won't pick up that a car has pulled into the space, so we discovered the sensors were set too high," Huffaker said. "We have adjusted the sensitivity."
This sensor malfunction seems to have surfaced only in some metered areas downtown and not others, he said. Walnut Creek received about 100 reports of sensor errors over the past several months.
Huffaker said the city has processed nearly 1 million meter payments, so the reports of malfunction involve less than 1 percent of the meter transactions.
"We have worked with the meter manufacturer over the past month to improve the performance. Over the past few weeks, we have received only a few reports," he said.
Huffaker isn't too worried that people who may have been wrongly ticketed and not spoken up and instead paid the $45 fine.
"It's possible, but in my experience when someone receives a parking ticket wrongfully ... they make that known," he said.
This sensor technology is fairly new and is also used in San Francisco. The sensors make it easier for city staff to monitor the parking system and is key in providing information to the free ParkMe app that allows people to see where spaces are open downtown, Huffaker said.
It also allows the city to verify if someone believes they paid for meter time and was erroneously ticketed, he said.
"We take every complaint very seriously, and for every parking space where we receive a complaint or question it is easy for us to look it up in the system and see whether or not someone paid," he said. "In the past, before smart meters, there was no way to look at that information and we would have to go on word alone or physically inspect the meter."
For years, the perception of Walnut Creek parking has been that it's a challenge to find any spaces downtown -- one reason new parking rates and meters were introduced last year. In doing this, officials knew there would be some growing pains.
"As with any new technology, implementation of our new parking meters and parking sensors has had some minor hiccups," said Mayor Kristina Lawson, who said she has received few complaints about sensor-related problems. She thinks the parking system is working well.
"I park downtown almost every day, and speaking from my own personal experience, the system is working as it is intended to -- freeing up metered parking spaces for quick trips and encouraging parking in the garages for longer stays in the downtown area," she said.
"I continue to believe that a comprehensive downtown parking management program, where both public and private meters and garages are integrated into one user-friendly system, will be key to the long term success of our downtown."
©2014 the Contra Costa Times (Walnut Creek, Calif.)