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Sunday Jams

This Sounds and Smells Fishy – More Noise Ordinance Follies

By Robert Canning

Almost a year ago, City of Davis staff attempted to slip a change to the City’s sound ordinance through the city council with little discussion and no commission input. The proposal was pulled back by staff after questions immediately arose about the intent and substance of the change, and how they related to a controversial (and noisy) piece of playground equipment in Arroyo Park.

Now, the staff are bringing a new proposal to the Recreation and Park Commission and asking the commission to review the report of a sound consultant and give “feedback” on new locations for the Sky Track equipment based on the staff report and a survey of Davis residents who live within 1,000 feet of the equipment. The staff report quotes at length from and discusses the sound consultant’s report. But basically, the sound consultant parrots the line from a year ago that the city should use the average of sound over time rather than the maximum allowable sound as the basis to evaluate whether the Sky Track produces is too noisy. 

It is puzzling why the consultants continue to use the Leq metric since that does not appear anywhere in the Davis Municipal Code section on sound (Sec. 24.020). In fact the ordinance specifically states that “Noise Level means the maximum continuous sound level or repetitive peak level produced by a sound source or group of sources…” It’s unclear why the staff report states on page 2 of the report that the consultants “determine that the “City Standard is a Leq”. Isn’t it the city’s job to tell the consultants what the code says? We shouldn’t be asking noise consultants to give a legal interpretation of the city code – to the city. And there is no timeframe referenced in the city code, which would be required if an average measurement is to be used. A change in the language of the ordinance regarding maximum allowable sound levels, as has been pointed out before, has ramifications beyond the issue of Arroyo Park and are akin to last year’s fiasco should not be contemplated without more public input.

In addition, the staff report directly conflicts with the municipal code. Below is the table displayed in the staff report under question 7 of the staff to consultants.


Yet the city’s code section 24.02.020 Noise Limits, shows the following table:


For comparison, a vacuum cleaner is about 75 dBA, a refrigerator 55 dBA, and city traffic 85 dBA (see https://ehs.yale.edu/sites/default/files/files/decibel-level-chart.pdf).

Another point: the staff report misrepresents “precision” and “accuracy.” An instrument’s precision is usually the range (plus or minus some value) around the target value to be measured which gives the observer confidence that “most” of the time (say 95 out of 100 times) the instrument is accurate.  Precision is independent of the source of sound to be measured and is often based on a control measure (like a standard tone). Accuracy is how close to the “target” the measurement is. For instance, a measurement of sound from one mile away would be much less accurate than one made within one meter.

Sound impacts at Arroyo Park are predicted – using the unfounded Leq, or average standard – to be within .5 dBA of compliance and the measurements have been made with good Type 1 instruments. Now this is what Wikipedia says about accuracy: "For compliance purposes, readings with an ANSI Type 2 sound level meter and dosimeter are considered to have an accuracy of ±2 dBA, while a Type 1 instrument has an accuracy of ±1 dBA.” (https://en.wikipedia.org/wiki/Sound_level_meter) In confusing precision for accuracy, the city is proposing action by the Rec and Park Commission based on readings not even within the accuracy of the measurements.

And if all this is not enough, staff continue to have problems with simple math. The numbers below the chart on survey page 5/11 do not match the narrative report on page five of the staff report. The commission should ask staff to “show their work.” 

Last year, the staff made statements that sounded fishy. I stated that staff needed commission input and to rethink their proposals for the sound ordinance to justify questionable decisions of a few years ago. This year they are appropriately coming before the Recreation and Park Commission with information. But the information appears flawed, and the staff’s report of their own survey makes no sense based on the numbers provided in the report.

These sorts of shenanigans and poor work on the part of staff have come up more frequently in the last few years. It’s time for the city council to demand better results from staff. Unfortunately, the city manager’s comment that “I think more work needs to be done on this item…” is still true.


Janet Krovoza

Sound measured at 70 dBA is FOUR TIMES as loud as sound measured at 50. City staff is attempting a complete backdoor runaround to change longstanding city standards without ANY public input or council involvement. All so they can justify keeping the Sky Track in Arroyo Park. Without such a change there is no way the Sky Track (aka "zip line") can remain in the park (it clearly violates both established day and night noise limits), and they know it.

Alan C. Miller

Thanks, Robert for posting this and keeping this ERROR in the news. Noise is unlike any other environmental toxin - it permeates the soul. And those who suffer are those closest to the source, and they suffer every day, as the concentrated output of the individual uses of many. No one should have to put up with such shˆt.

I know a bit about the effects of noise on the human ear, having suffered for 40 years with hyperacusis. PEAK noise, even in short bursts, is much more destructive to the auditory and nervous system than a moderate noise. So averaging out the sound levels, rather than taking into account damaging peak levels, is a crock of shˆt. That's the scientific term for it.

Tear down the zip line! Tear down the zip line! Tear down the zip line!

J.J. Surbeck

What an interesting article. Luckily, I don't live close to Arroyo Park, but I certainly can sympathize with the noise sufferers around it. What this situation illustrates is how noise pollution is not considered seriously by city staff... or pretty much everybody else for that matter. It IS a serious issue and most people suffer from it in lost sleep and increased stress and tension whenever they're hit by excessive noise, even if they don't always quite realize it. It's part of the culture, but that's no excuse, and as a matter of fact the culture needs to change in this respect.

People who make or cause excessive noise show first and foremost a complete disrespect for the right of others to live in a quiet environment. Granted, there are noises that are unavoidable, and we can all live with that. Less excusable is noise caused by people who don't care one bit what impact they have on other people's mental and physical health. To wit, I live three blocks from highway 80, and all I can hear at night is the almost incessant drone of loud motorcycles (and cars) whose owners removed the original pipes to replace them with loud ones (something that is clearly illegal and no one, least of all CHP, seems interested in stopping). Selfishness and pathetic egos is all that matters to them, and I don't see why this should be considered acceptable nuisance.

If we want to be a community of people who care for each other, one of the most obvious and most often forgotten ways to do so is to remain conscious at all times of the noise impact we all have on our environment and do our best to limit it to the lowest possible levels (particularly by playing loud music that no one asked to be forced to listen to). To help us, there are dozens of apps that measure noise levels, making it next to impossible to come up with excuses. Download some of them and start playing with them. You'll be surprised, not only by the noise levels you cause, but also the noise level self-absorbed individuals can make. It goes well beyond acceptable legal limits, and they should be called on it.

Joe Krovoza

Mr. Surbeck. thank you for your comment. You couldn't be more correct. Living day in and day out with the banging and scraping metal noises is exhausting. With the Sky Track disabled now, it's amazing how wonderful our time around the house has come enjoyable again. If anyone doubts your comment, your plight or ours, or thinks it's whining, spend time with this The Atlantic piece from November 2019: https://www.theatlantic.com/magazine/archive/2019/11/the-end-of-silence/598366/

Arroyo Park was wonderful without the Sky Track, and it will be once again when it's gone. Certainly the city is creative enough to find compatible, respectful uses. In fact, the park wasn't broken at all before this mess got added with ZERO public input. That staff -- and by extension the current city council -- don't understand respecting their own citizens is truly discouraging.

Ron O

"To wit, I live three blocks from highway 80, and all I can hear at night is the almost incessant drone of loud motorcycles (and cars) whose owners removed the original pipes to replace them with loud ones (something that is clearly illegal and no one, least of all CHP, seems interested in stopping). Selfishness and pathetic egos is all that matters to them, and I don't see why this should be considered acceptable nuisance."

I don't understand this, either. If you can hear it three blocks away, certainly the Highway Patrol can hear it as well. Easy-to-catch, if they actually wanted to enforce the law. (Same goes for local police.) In fact, it's obvious to anyone with ears.

As far as the zip line is concerned, this appears to be yet another unfortunate manner in which the city treated its own residents. (Essentially trying to "justify" it, after-the-fact.)

Karen L Baker

This is one more instance of city staff hiring consultants when the staff should be doing the research and presenting findings. As a taxpayer, I find the ongoing use of consultants troubling: it's expensive. Why are we paying for staff when they just hire out a consultant to perform the due diligence.

The fact that no input from residents is considered has led to the Mace Mess, the loud zip line and countless other projects. We need better oversight and competent management in our city...! Maybe some City Council leadership change would help?

Robert D Canning

A commenter elsewhere corrected my definition of "precision": Precision pertains to the least-count value of the reported measurement, and generally corresponds with repeatability. It is untethered from accuracy, i.e. an instrument can be very precise and wildly inaccurate at the same time.

Think of shooting a gun at a bullseye target. If you shoot 10 rounds that are grouped close together at the outer edge of the target, you’re precise but not accurate. If you shoot 10 rounds that are distributed evenly around the outer edge of the target, you’re accurate but not precise. If you group all 10 rounds close to the bullseye, you’re both accurate and precise.

Alan C. Miller

"i.e. an instrument can be very precise and wildly inaccurate at the same time."

I tried to follow that whole line of reasoning about the bullseye, and came to the conclusion that my brain isn't precise nor accurate enough to understand that metaphor.

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