Ride With Respect Noise Letter to Grand County and Moab City

This letter is being reprinted here with permission from Ride with Respect (RwR).

This letter was written by RwR to Grand County and Moab City regarding sound regulations. In the attached PDF there are letters from RwR and Grand County’s Motorized Trails Committee as well as copies of the City of Moab Utah approved noise ordinance and Grand County approved noise pollution ordinance at the end.


RwR Letter to Grand County and Moab City

Grand County Commission
125 E. Center Street
Moab, UT 84532

Moab City Council
217 E. Center Street
Moab, UT 84532

Dear Grand County Commissioners & Moab City Council Members:

Ride with Respect (RwR) applauds you for starting to take a serious look at sound regulations, and we appreciate the discussion you’ve had thus far, but the approved county ordinance and draft city ordinance need several adjustments before noise concerns can be resolved in a practical and lasting manner. RwR is addressing the county and city together because you are both addressing the same issue, both consulting with the firm Noise Pollution Clearinghouse, and both attempting to make your policies compatible.


First let me explain why RwR didn’t submit detailed comments prior to the commission meeting last Tuesday. In fact I was producing comments based on the April 16th draft that was posted on Grand County’s agenda center. After planning and hosting the third sound-testing demonstration on April 19th, the county attorney kindly sent me an updated draft, although it was not posted on the agenda center. I continued producing comments that evening and the following morning, only to receive an April 20th draft. Again, I appreciate receiving it from the county attorney, but it was not posted on the agenda center. In fact, at present the only draft posted on the agenda center is the original one from April 16th. Anyway the April 20th draft fundamentally changed how motorcycles would be regulated (from sound measurements to EPA labels only), further setting back my comment progress to the point that I couldn’t submit comments in time for your meeting.

Fortunately, unlike the ATV business-license ordinance and LUC that involved a moratorium deadline, the noise ordinance had no such deadline. I figured that I could explain the need for more time on the new draft of the noise ordinance but, during Citizens to Be Heard, comments on the noise ordinance were prohibited with the rationale that a public hearing on the matter already took place. In fact the drafts had changed so significantly since the public hearing that I think the county should allow and in fact encourage comment on the new direction. Instead of going into details, I simply emailed the commission and staff that I have serious concerns about the latest draft, and would appreciate more time to discuss it before voting on the matter. The commission voted anyway, and said that they can amend the ordinance anytime.

Also during the meeting, the county attorney said that the latest version isn’t in the agenda packet, but that I forwarded it to the ATV businesses and members of the Motorized Trails Committee (MTC). I did forward the ATV business-license ordinance and LUC drafts to ATV businesses 12 hours prior to the April 15th meeting in which the commission voted on them. I did it as a courtesy to the county attorney for emailing me the drafts 14 hours prior to the meeting, as no drafts had been posted on the agenda center at that point. However I didn’t forward the ATV business-license ordinance and LUC drafts to the MTC. Further I didn’t forward the draft noise ordinance to the ATV businesses or the MTC, and I hadn’t said that I would do so, just for the record. The process and decisions could be more thorough if given more time which, given the subject’s technical and consequential nature, is warranted in my opinion.


Second let’s recognize the progress made. RwR has promoted regulating sound for many years and, while the following points were initially challenged by local officials and people on both sides of the issue, we seem to be reaching agreement that:

  1. Education (e.g. Throttle Down) is critical but cannot fix the problem on its own,
  2. Engineering solutions (including alternate routes) are limited by private property in Spanish Valley,
  3. Lowering speed limits is likewise limited (primarily by side effects like reduced efficiency),
  4. Local government should utilize resources like sound testing before expecting industry reform,
  5. Local government shouldn’t count on the state granting permission to restrict the street use of UTVs,
  6. Quieter mufflers can bring the most popular UTV models in line with other sport models,
  7. Regulating sound should involve actually measuring sound in order to be objective,
  8. Measuring motor vehicles in use would be ideal but has major limitations for enforcement,
  9. Measuring motor vehicles while stationary can feasibly catch excessively-loud vehicles,
  10. Stationary sound testing can be done by pulling over vehicles rather than relying on a check point,
  11. Sound meter features (e.g. decibel averaging, tach synching, wireless comm.) aid enforcement, and
  12. Local government should consult an OHV sound expert for its noise ordinance and enforcement.

Stationary Sound Limits

For years RwR has advocated utilizing stationary sound tests for the specific vehicle types that the Society of Automotive Engineers (SAE) intended when developing them. Matching the intended test to the given type of vehicle makes enforcement more straightforward. For example, it’s important not to subject Type III ATVs (which are typically Jeeps with larger tires) to a test designed for dirt bikes (J1287), which the county’s approved ordinance does. Please refer to the Motorized Trails Committee’s March 15th letter:

“All-Terrain Type I Vehicle and All-Terrain Type II vehicle SAE J1287
92 dB

All-Terrain Type III Vehicle, automobile, and truck up to 14,000 pounds GVWR SAE J1492
95 dB

Off-Highway Motorcycle (any motorcycle that is designed for use on trails or natural terrain, regardless of whether or not it is also designed for on-highway use)
SAE J1287
96 dB

On-Highway Motorcycle
SAE J2825
96 dB for engine with less than 3 cylinders or more than 4 cylinders
/ 100 dB for engine with 3 or 4 cylinders

SAE J2567
82 dB”

Note that the MTC’s exemption for trucks over 14,000 pounds GVWR was simply based on the observation that 14,000 pounds correlated with other regulations, and it matched the GVWR of the most capable version of one-ton truck available. However after the lengthy discussion on GVWR on April 20th, it’s clear that the commission is not taking GVWR lightly, so I presume that the MTC would defer to your decision. After all, the MTC’s November 12th letter stated “Because the MTC represents enthusiasts of off-highway motorcycle, ATV, UTV, 4WD, and snowmobile recreation, we support requiring sound standards for those vehicle types (based on SAE J1287, J1492, and J2567 respectively). We encourage Grand County to approach enthusiasts of on-highway motorcycle, car, and heavy-truck use before requiring sound standards for those vehicle types.”

In February RwR facilitated a UTV sound-testing demonstration for county and city officials. We are glad to see that the approved county ordinance and draft city ordinance don’t limit UTVs to 88 dB by SAE J1287 for model years 2024 and later because it is unrealistic for manufacturers to achieve, especially when it comes their sport models, which are more suitable than utility models for 4WD trails in Moab. A 92 dB limit is justified given the higher levels of non-muffler sound when compared to off-highway motorcycles (aka dirt bikes) for which the J1287 procedure and 96 dB standard were developed (including UTVs’ greater sound from tires, drivelines, and the engine’s typical operating speed as well as its duty cycle due to the continuously-variable transmission (CVT) or even just the higher payload for models that lack a CVT). A 92 dB limit is attainable for all kinds of UTV, although it may require an aftermarket muffler like the HMF Twin Loop, but the additional cost will significantly help resolve noise concerns. This arrangement is similar to “closed course” models of motorcycle that should have an aftermarket muffler like the FMF Q series installed to bring them below a 96 dB limit.

On April 16th, RwR invited county and city officials to a demonstration with other vehicle types on April 19th, and we appreciate all five county officials who attended especially considering the short notice. In response, the county’s April 19th draft adjusted the automobile limit (from 88 dB to 92 dB by J1492), the dirt bike limit (from 90 dB to 92 dB by J1287), and the on-highway motorcycle (aka street bike) limit (from 90 dB by J1287 to 92 dB by J2825) before doing away with stationary sound testing in the April 20th draft. There is a lot more work that went into the MTC’s suggested limits (which are endorsed by their respective industry groups, enthusiast groups, and codified by many states).

For automobiles, all five states that codify a stationary sound limit by J1492 (or older methods that are equivalent) have chosen 95 dB. If Grand County regulates automobile equipment more strictly than these states, our own state legislature may intervene. Fortunately a 95 dB limit would be effective (especially in combination with other provisions of the draft noise ordinance like the one against throttle jockeying in addition to traditional tools like citations for speeding or reckless driving). The demo 4WD rig (a 2006 Wrangler TJ Unlimited) that measured 95 dB by J1492 did have an aftermarket muffler, but it is actually of a higher quality and lower sound than most other aftermarket mufflers, and the vehicle was not excessively loud when in use (i.e. passing by). It is one of many automobiles that measures over 92 dB by J1492 yet is not contributing to our noise problem. Even the demo sports car (2016 Ford Mustang GT with ROUSH Stage 3 conversion) that measured 93 dB J1492 is a lot quieter than the street racers that cause a nuisance downtown, which tend to have a rattle at certain RPMs that is captured by J1492 due to an RPM sweep (from idle up to the target engine speed, with the test result being at whichever RPM was loudest). Many car-show vehicles exceed 100 dB by J1492, and they could be exempted (based on time of day
/ location / manner of use) if you so choose. The 95 dB standard by J1492 is accepted by the Specialty Equipment Market Association (SEMA).

For dirt bikes, a limit of 96 dB by J1492 is the law in a dozen states including the surrounding states of NM, CO, WY, and ID. Your consulting firm used a small study from 2005 in California to justify a 90 dB limit. As mentioned in your workshop, the study’s actual recommendation is to allow at least 94 dB, and a lot of research has been done since then that finds some dirt bikes with mufflers labeled as EPA compliant measuring up to 96 dB in unmodified condition. The April 19th demo dirt bikes (2012 KTM 350 EXC-F and 2005 Honda CRF250X) with EPA-labeled mufflers measured about 92 dB by J1287, which the April 19th draft ordinance used as justification to set the limit at 92 dB. I have told the county and city that RwR has measured dirt bikes with unmodified EPA-labeled mufflers at well-over 92 dB, and this point has been confirmed by sound professionals who have measured thousands of vehicles. Yet on April 20th the county attorney continued claiming that all motorcycles can meet a 92 dB limit, and the city continues to propose this limit. A 92 dB limit requires exempting EPA-labeled dirt bikes, which creates a huge loophole for people to exploit by removing baffles or drilling out their stock mufflers. The solution is to adopt the 96 dB standard that can be required of every muffler regardless of its label. Further, a 96 dB limit would compel motorcyclists who have noisy mufflers to buy a quieter one because they know it would achieve compliance. However many of them would fail to find a replacement muffler that reliably measures under 92 dB so, if the limit is set at 92 dB, they would be less likely to get a quieter muffler and more likely to just try to evade enforcement.

A final note on dirt bikes is that the county’s April 19th draft proposed to subject street-legal dirt bikes to J2825, which was not designed for any kind of dirt bike, and in fact would be too lenient for dirt bikes given that J2825 tests single-cylinder motorcycles at just 2,000 RPM (which is justified for street bikes because they tend to have more torque to essentially idle through town). Therefore we encourage using the MTC’s suggested definition of an off-highway motorcycle “any motorcycle that is designed for use on trails or natural terrain, regardless of whether or not it is also designed for on-highway use.” This will capture dirt bikes, dual-sport bikes (i.e. street legal dirt bikes), and adventure bikes (which are larger and more street-oriented but still somewhat capable on dirt). All of these models are listed in the J1287 supplement (that shows the test RPM for each model), so they should be subject to J1287. Then the ordinance could regard all motorcycles not designed for use on trails or natural terrain as “on-highway motorcycles” subject to J2825.

Regarding street bikes, it was good to see the county’s April 19th draft utilize J2825, but it should distinguish between 3- and 4-cylinder street bikes (which are tested at 5,000 RPM) and all other street bikes (which are tested at 2,000 RPM) for reasons explained in the SAE publication “”Development of the J2825 On-Highway Motorcycle Sound Test”” that I shared at the April 19th demo. The limit for on-highway motorcycles should be 100 dB for engines with 3 or 4 cylinders and 96 dB for engines with less than 3 cylinders or more than 4 cylinders. For one thing, the SAE does not advise using J2825 to enforce limits below those figures. For another thing, those standards are law in NH and other parts of the U.S. as well as Canada. The demo touring-oriented street bike (2008 BMW K1200GT, which has 4 cylinders) measured 95 dB by J2825, and sounded quiet under normal operation because it could pass by at less than 5,000 RPM. Since your consulting firm asked about another unit of the same model, yes, I measured it at 93 dB. Since your consulting firm asked about maintenance, I should point out that most stock mufflers are a mechanical design that doesn’t require repacking like many of the fiberglass-insulated aftermarket mufflers do. The primary way to reduce the sound of a K1200GT would be to replace the muffler, which BMW sells for over $1,500. The 96/100 dB standard by J2825 and 96 dB standard by J1287 are accepted by the American Motorcyclist Association (AMA) and Motorcycle Industry Council (MIC). Only by adopting these standards (or more lenient ones) can stationary sound limits be enforced on all motorcycles regardless of the labels on their mufflers. In other words, if you set limits stricter than 96 dB, you won’t close the enormous loophole that allows mufflers to be extremely loud so long as they have EPA labels.

On April 20th, the county attorney urged abandoning stationary sound testing for motorcycles, stating “The other issue is that there are two different SAE tests that are applied to motorcycles. And again we’re just getting into more complication. So now we’re asking law enforcement; it would be three total tests. Off-road would be the J1287 test. You’d have vehicles at J1492. And then you’d have street bikes at 2825. And again it’s an additional test, an additional complication for law enforcement for probably very little to zero increased enforcement effect.” While officers should be trained to conduct stationary sound testing properly, once you know how to conduct one test, it’s easy to learn a second one. They typically vary in just a few ways, and it becomes routine with practice. The complication of learning three tests is far exceeded by the complication of applying a test to different vehicle types than what the SAE intended. The notion that, compared to requiring EPA labels, enforcing J1287 and J2825 offers very little to zero increased effect on curtailing noise is completely wrong.

Data Sources

Your consulting firm insisted that all motorcycles with unmodified mufflers in decent working order will measure under 90 dB by J1287. The April 19th demo disproved this assertion, and really it should’ve been common knowledge for anyone who has worked in sound regulation for that past quarter century, not to mention the common knowledge that J1287 is not the appropriate stationary test for street bikes. Yet on April 20th the county attorney appeared to be unconcerned, and recommended that the commission hire your consulting firm to help the city police and the county sheriff create a data management plan. Likewise the consulting firm has made poor suggestions to the city, such as prohibiting heavy trucks from idling for more than one minute, which the MTC addressed with the city attorney before she extended it to five minutes.

In contrast, I tried to understand more about the consulting firm. The final report of “Noisy Motorcycles—An Environmental Quality-of-Life Issue,” a roundtable sponsored by The INCE Foundation and The Noise Control Foundation in 2013, states:
“Representing the public, Les Blomberg from the Noise Pollution Clearinghouse expressed concern that the SAE J2825 is not strict enough. Because the SAE procedure is quite different from the current federal procedure, he stated there are motorcycles that would fail the EPA test, but pass the SAE test. He would prefer to see an alternative test that would fail every vehicle that is failed by the EPA test. He also wants to make sure that any wording change in the regulation would not require a vehicle to pass the EPA test or the J2825 test. His concern is that such language would allow a driver who fails J2825 to claim that his motorcycle passes the EPA test, which an enforcement officer can’t determine. Roundtable participants agreed not to recommend a change in the requirement that motorcycles meet the EPA test standard.”

The consulting firm appears to expect perfect enforcement of EPA standards in the field despite obvious limitations that are inherent to all motor vehicles (not just motorcycles). Likewise the consulting firm has advocated banning car alarms and the use of cell phones in public spaces (presumably to talk, not to text). I can relate to the irritation of false alarms and loud phone talkers, but there appears to be a pattern of unrealistic positions. This approach is more characteristic of an advocacy group, and in fact the consulting firm is a 501c3 organization, with past support from Sierra Club and NRDC. The firm’s own website touts the fact that CBS News Sunday Morning declared the firm to be “The nation’s major anti-noise interest group.” How county and city funds are spent is not up to me, but I’d like you to know what you’re getting, and how the work may be perceived by affected vehicle owners, businesses, and legislators.

EPA-Label Requirements

As alluded to in the section on stationary sound limits, thousands upon thousands of EPA-labeled mufflers in use are unacceptably loud, whether through internal modification or decades of deterioration. For example, consider the loudness graph that your consulting firm dramatized by stretching the scale, equating to semi-truck sound levels (even though the 80 dB federal pass-by standard is at hard acceleration, and motorcycles wind up going a lot faster in that test than semi-trucks, so it doesn’t mean that motorcycles are as loud as semi-trucks when following the same flow of traffic), and exploiting the diminishing effect of additional vehicles (e.g. the total sound of 50 semi-trucks simultaneously passing isn’t much more than that of 32 semi-trucks). The consulting firm’s conclusions relied primarily on a single motorcycle that measured 95 dB by J1287 yet 97 dB by the federal pass-by test (i.e. it passed California’s stationary standard yet exceeded the federal pass-by standard by 15 dB). That particular motorcycle, a KTM 525 EXC, had a stock muffler with an EPA label. Even if that motorcycle got louder, it would continue to pass an EPA-label requirement, but would fail to pass a 96 dB limit.

Meanwhile thousands upon thousands of mufflers lacking the EPA label are reasonably quiet, which makes EPA label requirements grossly ineffective at curtailing noise. On April 20th the county attorney stated “100% of motorcycles tested that did not have the EPA stamp required under federal regulation fail 92 dBA at 20″ and 80 dBA at 25′ standards.” First of all, that was a sample size of two motorcycles, where as I have been motorcycling for a quarter of a century, and am keenly familiar with noise culprits, which is a function of the muffler far more than the model of motorcycle. For example, all modern two-stroke dirt bikes lack the EPA label, but most of them have more torque than older versions which allows riders to keep the engine speed low, and the sound dissipates faster than four-strokes. Modern two-strokes are among the quietest dirt bikes despite their lack of EPA labels.

The demo dirt bike with a stock muffler that has no EPA label (2021 KTM 350 XC) measured over 98 dB by J1287. RwR agrees that this is too loud, and the owner is in the process of adding a cap to reach 96 dB or a whole new muffler such as the FMF Q to reach 94 dB. As the bike deteriorates or is accessorized with things like metal skid plates that reflect sound back toward the muffler, this bike will not meet a standard lower than 96 dB. Although RwR encourages EPA compliances, and we walk the walk with our own bikes, there are many reasons why people choose “closed course” models. Skilled youth riders depend on them because they quickly out-grow the entry-level models. Women often prefer the lighter weight of two-stroke engines, all of which are still “closed course” despite major emissions improvements from fuel injection. Racers would rather not spend another ten-thousand dollars on a second bike for non-race riding.

The most popular brand of dirt bike is KTM (which sells alternate models under the Husqvarna and Gas Gas brands), and the vast majority of its dirt-bike models are “”closed course,”” which could be outfitted with a quiet- oriented aftermarket muffler to meet a limit of 96 dB but not 92 dB. Note that quiet-oriented dirt bike mufflers almost always have spark arrestors. On April 20th the county’s commission administrator pointed out that you can’t legally ride a closed-course model on federal property because it lacks a spark arrestor. However the lack of a spark arrestor actually compels most riders to replace the muffler or at least the end cap, both of which reduce sound for most models. Further, enforcing the spark-arrestor requirement is a better indication of reasonable sound levels than an EPA-label requirement would be. Spark arrestors are also easier than enforcing an EPA-label requirement (by simply inserting a metal wire in the outlet to ensure that it’s blocked by the presence of a spark arrestor).

Verifying EPA labels is often challenging in the field. The labels are required of manufacturers, not consumers, which anticipates that the setting of an inspection would be a showroom floor or dealership service department rather than roadside after thousands of miles of use. Consequently the EPA labels on brand-new motorcycles:

  1. Lack a contrast with their background on virtually every model,
  2. Are placed in a location that’s subject to grime or rubbing on most models,
  3. Are placed in a location that requires laying down to view on many models,
  4. Are placed in a location that requires minor disassembly (e.g. heat shield) to view on some models,
  5. Are placed in a location that requires major disassembly (e.g. rear wheel) to view on some models, and
  6. May be removed by the consumer without violating EPA regulation

For examples, see this report from motorcycle advocates in New York City:
The lack of contrast is probably due to the fact that the external surface of motorcycle mufflers routinely reach 200F. Extreme heat is the same reason that most EPA labels aren’t “stickers” despite how some people continue to refer to them. When your consulting firm suggested using a glove to wipe mud off of muffler to find an EPA label, I wonder if they know that mud from Mancos Shale and other bentonite clay hardens around mufflers like pottery in a kiln. The EPA labels on mufflers are often worn by tire rubbing, and blocked by accessories like storage boxes. To truly verify a label, officers should match the unique code on the muffler label with the unique code stamped on the headset (separate from the VIN), which indicates that the muffler is EPA compliant for use on that particular model of motorcycle. The EPA label on the headset is often worn by cable rubbing, and blocked by accessories like aftermarket fuel tanks (requiring tools to disassemble).

The county attorney said that finding the EPA label was easy on all of the roughly twelve motorcycles that she has tested and/or inspected. I know that she tested one of my motorcycles that does not have its EPA label visible without removing a storage box, which we did not do. Also, once the storage box is removed, an officer would find that the EPA label is upside down and heavily obscured by grime despite that the label faces outward and is only three years old.

On April 20th the county attorney asked “The stamp is required by federal law, so why not leave it there? Why are we incentivizing by creating this loophole for people like the street-bike that we tested, for an individual to buy an illegal muffler when there are millions of mufflers out there that are legal?” As I’ve said, it’s not required of the consumer, and the real loophole is exempting EPA-labelled mufflers from being sound tested. Mufflers lacking an EPA label is no loophole because they would be sound tested just the same. Further there are not millions of mufflers out there with EPA labels for most closed-course models, models that are roughly 25 years old, or custom builds. EPA-labelled mufflers are not only more expensive, but they’re unattainable for a substantial portion of motorcycles.

Regarding the reach of motorcycle sound limits or EPA-label requirements, on April 19th the county attorney and commission administrator assured me that the latest draft confines such requirements to Class B roads with the intention of being confined to street-legal motorcycles in residential areas. However the county’s approved ordinance makes no such confinement, while it does confine the pass-by sound limits to Class B roads. The ordinance provides a separate definition of street-legal motorcycles from other motorcycles, so it could’ve easily confined the EPA-label requirement to street-legal motorcycles. Although the ordinance identifies residential areas as its primary goal, it also identifies balancing the natural quiet of the surrounding desert landscape as a secondary goal, which could be used to justify enforcing motorcycle sound limits or EPA-label requirements virtually anywhere in the county.

Even if it were limited to residential streets, most access roads to the nearby trails are residential. On April 20th the county attorney dismissed the idea that closed-course models are converted to be street legal by stating “There was an admission that they [closed-course models] are not comfortable to drive on the streets.” This refers to a conversation she had with a Marine Corps veteran who certainly couldn’t have been referring to the brief street riding needed to reach trailheads or to connect with other trails and towns. He must have been referring to long-distance highway riding, which isn’t the only reason to make one’s dirt bike street-legal. Not only is riding to the trail easier than trailering, it’s less consumptive, as dirt bikes on the open road get better fuel economy than hybrid cars. Also please keep in mind that rules pertaining to Class B roads that are graded dirt would still affect all dirt bikers. Rides are commonly 50- to 100-miles long, and graded roads are needed to connect trails.

Similarly the city’s draft ordinance states that motorcycle EPA-label requirements, pass-by sound limits, and stationary sound limits (including the much lower ones during restricted hours) would apply to all public roadways. Moab City includes parts of 4WD trails like Hells Revenge and Moab Rim, which are Class D roads. Therefore all of those requirements and sound limits would apply to street-legal and non-street vehicles alike, and justifications like “just trailer to the trailhead” aren’t any consolation. RwR actually encourages making sound regulations reach beyond residential areas to the public lands so long as they’re reasonable. Stationary standards like 96 dB by J1287 for dirt bikes wouldn’t need distinctions (e.g. city/county, residential/non-residential, paved/dirt, road/trail), rather they should protect all of the county all of the time.

Now that our convictions are clear, please stop asking motorcyclists to follow an EPA-label requirement that applies to manufacturers, while telling them not to worry about this aspect of a new noise ordinance being enforced. Instead make prudent rules that can be enforced uniformly, and I promise we’ll help through peer pressure.

Restricted Hours

The county’s approved ordinance and city’s draft ordinance that reduce the pass-by sound limits 2 dB during nighttime might work since the reduced traffic should enable reduced acceleration. However the city’s proposal to limit all vehicles under 10,000 pounds GVWR to 85 dB by a stationary test would effectively place a curfew on a substantial minority of cars/trucks and the vast majority of motorcycles / UTVs. Stationary sound tests are an equipment requirement, and the equipment obviously doesn’t get quieter at night, so it’s essentially a method to exclude certain vehicle types. It would not help the city in earning trust that it would regulate vehicles reasonably, as you’d have some restaurant workers unable to use their only vehicles, not to mention tourists trying to get going before 9am on a Sunday in the summer.

Pass-By Sound Limits

During the April 19th sound demonstration, we made rough measurements of the demo vehicles followed by even rougher measurements of traffic on Mill Creek Drive. Keep in mind that we mostly measured vehicles in the downhill direction, which are several decibels quieter than vehicles in the uphill direction, which are several- decibels quieter than vehicles on a steeper hill or accelerating from a stop. The presentation during the April 20th commission meeting indicates that pass-by limits would be used primarily at intersections for acceleration. Therefore the limit at fifty feet should be raised from 74 to 80 dB, which is the federal standard for on-highway motorcycles (and 2 dB less than the federal standard for off-highway motorcycles or semi-trucks). While these standards involve hard acceleration that can usually be avoided in everyday use, non-stock tires and other common accessories add to the total sound, which makes 80 dB appropriate for enforcement purposes (provided that the ordinance specify a recognized test methodology). If the ordinance specifies that pass-by limits are only for screening, or only for cruising on fairly flat ground, a limit under 80 dB may be appropriate. Just keep in mind that 80 dB at fifty feet is low enough to catch all of the worst offenders.

Perhaps pass-by limits are deliberately strict to compensate for a lack of enforcement. The idea would be that, when people know that they’re in violation, they’ll at least mind their manners. One limitation of this approach is that the “violators” eventually catch on to the empty threat of enforcement. Another limitation is that being labelled a “violator” can breed contempt. It can also be problematic for officers who will be accused of picking on certain “violators” arbitrarily, while being accused of failing to act by other citizens who will expect enforcement to its fullest extent. If you set a low limit now with the intent to provide a cushion, that intent may be lost as the years go by. Let’s retain good officers by giving them reasonable standards to enforce closely and consistently for everyone’s benefit.

Property Line Sound Limits

The city’s proposed residential property-line sound limits of 55/50 dB for day/night are too low, and even the county’s approved limits of 60/55 dB for day/night are too low considering the Fast sound-meter setting that’s specified. Such limits would be exceeded by a single bounce of the basketball, bark of the dog, or shut of the tailgate. Unless they’re far louder, such fleeting sounds are not the issue, which is why environmental sound readings usually average over the course of minutes or even hours. If this duration is deemed impractical, then at least specify a Slow sound-meter setting, or set limits significantly higher than 60/55 dB. The need to list so many exemptions is an indication that the limit is too strict.

Plainly-Audible Sound Limits

The city’s draft ordinance prohibits vehicle sound that’s plainly audible from a distance of 1,000 feet. “Plainly audible” standards are more appropriate for larger city’s that consistently have a higher ambient sound level. The Moab city limits includes relatively remote settings. Even on Main Street, there are times when normal operation of a normal vehicle is plainly audible from a distance far greater than 1,000 feet. Therefore the “plainly audible” standard should be limited to places and times when the ambient sound is consistently high, or it should be extended to a distance of 2,000 feet.

The city’s draft ordinance also sets limits in terms of dBC, which captures inaudible sounds, and is difficult to get repeated and confirmable results. Fortunately it’s generally needed only for industrial zones involving very low frequency sounds, so it could be removed from the city’s draft to reduce the burden of enforcement.

Vehicle-Owner Liability

The city’s draft ordinance makes vehicle owners liable for the sound produced by their vehicles when operated by another person. This may make sense when it comes to stationary sound limits because they’re an equipment requirement. However it makes no sense for pass-by or plainly-audible sound limits, which measure the manner of use. Vehicle owners should not be held responsible for the behavior of drivers when it comes to noise any more than speed or recklessness.

Sound-Meter Response Setting

“The county’s approved ordinance and city’s draft ordinance define “dBA” as the sound pressure level using the “A” frequency weighting and the fast response setting (unless otherwise noted or required by testing standards established by the county). The Fast setting measures sound in less than two-tenths of a second, often capturing spikes that aren’t detectable by human hearing, and yielding inconsistent results. Recognized test methods that call for a Fast setting either specify a long duration (in the case of environmental sound measurements) or a series of measurements that prove to be consistent (in the case of some vehicle sound measurements). The sound ordinances should define the Slow setting by default (unless otherwise noted or required by testing standards established by the county/city), as this provides a time sample of at least one second.


The city’s draft ordinance prohibits motorboat operation from exceeding “a sound level of (a) 80 dBA at 50 feet; or (b) 70 dBA at any shoreline; or (c) 80 dBC at any shoreline.” The state of Utah already quantified the sound limit for motorboat mufflers in R651-222 (enclosed). For engines manufactured after 1992, the state limits sound to 88 dBA by the SAE J2005 stationary test. This test appears comparable to the city’s proposed limit of ” 80 dBA at 50″ feet,” with the state’s limit being 8 dBA higher. The state also limits sound to 75 dBA by the SAE J1970 pass-by test, which appears to be comparable to the city’s proposed limit of ” 70 dBA at any shoreline,” with the state’s limit being 5 dBA higher. If so, the city shouldn’t set equipment requirements stricter than the state’s, as equipment requirements are primarily set by states. Instead the city could include the state’s motorboat muffler rules if it would aid enforcement.


Although the rationale may be verbose, RwR’s suggested revisions are specific and pragmatic, and I would be happy to answer any questions or concerns in the coming days. Thank you for considering all sides of this critical issue.

Clif Koontz
Executive Director