Print Page | Contact Us | Sign In | Become a Member
Quarterly: Summer 2020 - Lynn Bashaw

Audit of On-Street Parking Meters

By Lynn Bashaw


It’s Just Parking…

The Sacramento City Auditor’s Office completed an Audit of On-Street Parking Meters in February 2019. The audit was requested by Council to determine why there had been a significant spike in dismissed citations issued to motorists that were using the City’s new “smart” parking meters. News articles suggested that the City’s parking enforcement officers were issuing phony citations as a way to bump up fee revenue. Council asked us to investigate and get to the bottom of it.

Approximately 4,500 of the City’s on-street parking meters are now equipped with vehicle-detection sensors, solar rechargeable batteries, wireless capabilities, and multiple payment options. These enhancements are designed to improve the customer experience and provide significantly more data for the City to use in trend analysis. However, even the vendors that manufacture and sell these meters acknowledge that they are not perfect.

The accuracy of parking meter systems can vary based on the meter’s sensitivity settings and the environment the meter is placed in. Parking meters are generally placed outside where they are exposed to all manner of elements, which can impact their effectiveness.

We began our audit by learning all we could about parking meter technology. We wanted to know what made these meters tick and if there were any weak points in the system. To do this, we interviewed the meter shop team that charged and repaired the meters, we talked to our third-party meter vendor, reviewed the schematics for the specific meters we used, walked around and tested hundreds of on-street meters, obtained access to the data management system, went on ride-alongs with parking enforcement officers, and reviewed adjudicated citation data. What we found was that parking is not as simple as it sounds, there is an entire industry devoted to optimizing the way we park.

Accuracy is Everything

The contract with our parking meter vendor states that the sensors shall “provide greater than 95% average accuracy in detecting when the occupancy status of a parking space has changed due to the presence or absence of a motor vehicle that is parked within the delineated boundaries of the parking space.” This simple graphic depicts how a parking meter sends out a signal to detect the presence of a vehicle in each space.

We compared the sensor activity recorded in the system to our observation of hundreds of meters to determine whether the sensors were accurately recording and reporting what we had observed. As shown in figure below, only 83.5% meters passed the test. This fell short of the 95% accuracy rate required in our contract.

During our testing, we also noted that 4.25% of the meters failed because they ran out of power and went into “sleep” mode.

Watch Out for Meters Taking a Nap

Smart parking meters will shut down and go into sleep mode until they receive enough solar energy to turn back on, or until the depleted battery is replaced with a fully charged battery. We wanted to see how often meters were shutting down and the impact this had on parking operations. In the figure below, the solid line shows the number of individual meters that reported a critical battery and the dotted line represents an overall trendline.

It appears the critical batteries follow a cyclical pattern with more critical batteries occurring during winter months and fewer critical batteries during summer months. This data aligns with the City’s 311 call center data which also indicated a high correlation between non-sunlight hours and the number of broken meters reported to the City’s 311 call center.

The significant increase in the percentage of meters reporting critical batteries during winter months may indicate that the meters are not receiving a sufficient amount of sunlight exposure during these months to compensate for the amount of energy being expended. The percentage of parking meters reporting a “bad” or low battery ranged from 2% to 23% per day, depending on the time of year.

Low-battery meters may not have enough power to accept payments or report occupancy status, which could lead to reduced meter revenue and inaccurate occupancy information. It could also contribute to a poor customer experience as users may not be able to make a payment.

The Wi-Fi is Down Again

In order to evaluate the flow of payment information, we developed the figure below that depicts the steps in the process when a motorist pays to put time on a parking meter using a smartphone app. This process shows how the payment transaction starts at the cell phone and moves via a wireless signal to the payment system. The signal is then routed back to the phone and to the meter, which then both display the amount of time remaining.

Any point of failure in this process could result in a parking meter not receiving the payment signal and failing to turn the meter light from red to green. The meter light is what lets a City parking enforcement officer know if the meter has been paid or not. If a car is parked at a meter and the light is red, they are likely to receive a citation. During our review we found that a number of citations were issued in error when one of the City’s wireless carriers experienced an outage for multiple days.

Case Dismissed!

Contested citations may be dismissed for a variety of reasons. A dismissal does not necessarily mean that the enforcement officer made an error in issuing the citation. Some valid citations are dismissed as “warnings” and others may be dismissed when it is difficult for the hearing officer to make a conclusive determination based on the evidence they have available. In calendar year 2017, the City received over 23,000 parking-related citation disputes.

We used citation data to develop the figure below, which displays the number of dismissed and upheld citations by month. From the beginning of calendar year 2015 through mid-2016, more citations were upheld than were dismissed. However, starting in August 2016, City staff began dismissing more citations than they were upholding.

We found that the increase in the number of dismissed citations beginning in mid-2016 was attributed to citations that were dismissed for issues related to newly installed vehicle-detection sensors that needed to be calibrated. The spike in dismissed citations in October 2017 was attributed to a wireless signal carrier outage that occurred during that month. While there were some significant spikes in the number of citations dismissed during the period we evaluated, the number of upheld citations remained relatively steady indicating that enforcement was not receiving additional revenue from the erroneous citations.

What Did We Learn?

Our audit found the implementation of new smart meter technology came with a learning curve. Vehicle-detection sensor readings were not as accurate as our third-party vendor claimed. Some meters would incorrectly reset to zero, making it look like the motorist had not paid the meter. Low batteries were causing meters to go into “sleep mode” and shutting down when they ran out of power. The audit was able to quantify the extent and impact of these issues. It also put to rest the debate over whether parking enforcement officers were issuing erroneous citations on purpose; surprise! they were not. We recommended the Parking Services Division work with our third-party vendor to improve sensor accuracy rates, battery life, and communication issues, with the goal of improving the customer service experience and reducing the number of incoming disputed citations.

About the Author

Lynn Bashaw joined the Sacramento City Auditor’s Office in May 2013 where she leads a talented team of auditors who are passionate about improving City operations. Prior to joining the City of Sacramento, she worked as an auditor for the California Earthquake Authority, Golden 1 Credit Union, Alaska USA Federal Credit Union, and National Credit Union Administration where she performed operational and compliance audits. Ms. Bashaw holds a Master of Business Administration degree from Western International University and a Bachelor of Arts in Economics from California State University, Sacramento. Ms. Bashaw is a Certified Internal Auditor (CIA) and a Certified Information Systems Auditor (CISA). Ms. Bashaw currently serves as President of the Sacramento Chapter of The Institute of Internal A