Visual estimation of de-icing salt: Trials at 3500 University Ave, 2/20/26

Purpose

The purpose of this site inspection was to...

• Test Peter Gascoyne's salt distribution photos to determine whether they can provide a quick and easy way to roughly quantify the amount of salt applied to an area. 
• Develop a method, and protocol, that would maximize accuracy, speed, and documentation of amounts of salt.

This link displays all photos, with captions, in order.

Methods

Inspection location 

This is the location of the University of Wisconsin Extension, a large building with numerous sidewalks parallel to streets and leading from parking to the building entrances.  All sidewalks had been salted this morning, but there was no evidence that the parking pavement had been salted.  Sampling lasted from about 1:00 to 5:00 pm on Feb. 20, 2026.  I had sampled the site earlier, so I knew today's salting was normal, and that rain had removed all previous salt.

The sidewalk concrete at this location is relatively new, light in tone, and uniform in texture, making it excellent for comparing photos to pavement (except that the light tone minimizes contrast with salt).  Foot traffic is light (about one person every two hours), reducing any pulverizing or dispersal of salt by feet.

I spoke to the Building Manager, Ms. Stevie Seltman, stevie.seltman@wisc.edu., whom I met while sampling.  She knows the site is oversalted and has complained.  She said she would file a complaint with building inspection. 

The contractor salting the sidewalks is Maple Leaf Landscaping, 608-845-2203. The parking areas are salted by a different contractor.  The contracts for salting are managed by U.W. Groundskeeping, which does snow removal for the central campus.  Private contractors, rather than Groundskeeping, spread salt at 3500 because this location is separated from the university, but U.W. Groundskeeping still controls the contracts for work at 3500.  If there's ongoing snow or some other problem, the Custodian at 3500 may become involved.  So, there are 4 entities who may become involved with snow and ice removal at 3500.  The onsite Building Manager has control of only the Custodian.

Weather

Conditions for sampling at this site and time were near ideal because...

• Foot traffic is very low.
• Concrete sidewalks are smooth, uniform, and relatively new.
• Prior salting was removed entirely by rain the previous night. 
• Light snow triggered the salting, but all snow melted before sampling.
• Meltwater mostly dried before sampling.
• There was probably too little wind to blow salt off the pavement.

Moderate rain fell for several hours on the evening of 2/19, followed by temperatures dropping below freezing, then about half an inch (or less) of snow.  Salt stains I had noticed on previous days were now gone.

When I arrived at 1:09 pm, all snow on the pavement had melted, although there were a few small patches of snow on the grass.  The areas of pavement with more than light salt were still damp (dark in tone) but quickly dried within an hour or two during sampling.  Wind prior to and during sampling was 10-15 mph, probably not enough to blow salt from the pavement, and about 1/3 of the salt was lightly adhering to the pavement anyway.

Since this was my first test of PG's photo standards in the field, myimethods changed from one sample to the next as I gained insights.

Observations and Results

Overall distribution trends

Salt distribution along the sidewalks was highly non-random or clumped.  Some squares had barely any salt, while others had much more salt.  I took many photos showing half or more of all the pedestrian walks.  There was even one substantial salt spill near the back entrance containing multiple small piles.

A distinctive pattern of salt distribution (right) suggests "sowing" by hand or from a scoop.  The pattern resembles a "comet" with a blurry head, connected to a longer tapering tail

Besides clumping, another visible trend was for salt application to be heavier towards the entrances, on the one stair, and on other areas of concentrated traffic, such as where sidewalks meet the streets.

I could see numerous places where salt had scattered onto the lawn or shrub beds, within a few inches of the pavement.  It's probable this wasn't caused by wind, but by bouncing/scattering when applied.  I took a few photos (right) of the spillover but made no attempt to quantify how much or how far the salt had strayed.

How much salt was dissolved by meltwater?

I don't believe there had been enough snow--with resulting meltwater--to significantly reduce the amount of salt I could see or collect.  There were just a few places where significant dissolution of salt may have occurred. This combination of clues--no salt areas with sharp borders, plus salty footprints nearby--indicates the no-salt areas had been shallow puddles, with some flow-through, that were now dry. Link to photo.

Except for where the footprints originated, there were no salt stains on the pavement to suggest significant dissolution or aqueous transport of salt off the pavement.                                   

However, the salted areas remained slightly damp (wet) for an hour or so after I arrived, so a small amount of salt could be distributed in a fine solid film on the concrete surface or have been absorbed a short distance into the concrete.

In two places where I collected salt, about 1/3 of the salt particles were lightly adhering to the pavement, but I was still able to use the dust bin to easily scrape all particles towards the center for final collection with a fine brush.  This "adhesion" suggests a small amount of water surrounded some particles, then dried--indicating partial solution of these particles. But it was probably not enough to substantially reduce the salt collected.

How can salt disappear before samples are collected and weighed?

• Dissolution by rain, meltwater, or adsorption of humidity. See above.
• Wind. After a windy day, nearly all of the salt at 3500 Univ. Ave disappeared.
• Bouncing and scattering during application.
• Disturbance by foot traffic grinds to smaller particles, disperses salt, and can track out salty footprints.
• Collecting is incomplete, because some particles scatter or adhere, or wet salt binds to surface.
• Accidental loss at all stages, including weighing.  Salt is slightly sticky; small amounts (1%?) tend to stay behind during each transfer (from brush to dust bin to transport container to scale.)
• Salt before application may contain rocky material as a contaminant. I did find a rocky particle about 1/8 in diameter in sample #9.  I know it was rocky because it didn't dissolve in water.  But I don't know if it was in the salt applied, or was introduced later.

Quantification of salt at 10 sample sites

To estimate salt on a site, I used PG's photos (Draft 1, calibrated by volume or weight, right), trying to match the pattern I saw on the pavement to the pattern displayed in the photos.

I call the collage of photos on the right the "field standard."  It's used to estimate salt on a "field sample." The "field sample" may be a patch of sidewalk visually observed, or a photo of that spot.

The weights listed for each photo on PG's field standard represent the total weight of salt, scattered at various rates, on 250 square feet (or 10 sidewalk squares measuring 5 x 5 feet).  Therefore, to calculate how much salt you could ideally collect in the field from a 1 sq ft patch of sidewalk: Multiply its "weight in lbs" printed by the photo on the field standard, x 16 oz, all divided by 250 sq ft.

Photos stored on Flickr show the context of all sample sites, plus verticals and closeups of each site.  Obviously, sampling only the heaviest spots will bias results towards "oversalting."  These context photos allow an observer to judge how representative the sampling locations are.

When selecting sample locations, I selected places of heavier salting-- the head of the "comet" described above, which were found on all walkways.  Sites were selected in part because they were close to my vehicle (as you might expect an inspector to do).  But I did not seek out the very heaviest clumps of salt.  So I feel the sample locations are broadly representative of the many spots where a handful of salt landed.  But not representative of salt in between these "landing spots."

Having picked a sidewalk square with fairly heavy salt, I then focused on a smaller area, roughly 18" square, that had the heaviest concentration.

For each spot, I picked a square (or photo) on PT's "field standard" representing a "weight" of salt that I thought matched best.  Then I picked an adjacent square on the standard I thought matched second best. 

I found myself using how many particles touched one another as a helpful cue.  The apparent nonrandom distribution of the particles in the "field standard" made it a little harder to compare photos to pavement.  

The photos below show each sample spot.  For scale, use the width of the clip board, which is 9 in.  Sites #8 and #9 where I swept a salt sample have a blue template 12 inches square.  The salt was collected by sweeping with a soft brush towards the center, then using a plastic dust bin to scrape sticking particles towards the center. Finally, I removed all gathered particles with the brush by sweeping repeatedly into the bin, taking care not to scatter any.

Each estimate below is the weight of salt given on PG's chart (after making the conversion calculations described above).  The bold number is my best match of one of PG's photos to the field sample.  The non-bold number is my second best match.  Click on an image to enlarge it.

#1:  30 oz-----40 oz   per 250 sq ft

#2   15 oz-----20 oz   per 250 sq ft

#3    30 oz-----40 oz   per 250 sq ft

#4   10.5 lb-----13.5 lb   per 250 sq ft

#5     13.5 lb-----16.5 lb   per 250 sq ft

#6     13.5 lb-----16.5 lb   per 250 sq ft

#7    20 0z-----30 0z   per 250 sq ft

#8     9.0 lb-----10.5 lb   per 250 sq ft     Salt swept up=0.4 0z.  Note the large 2 white spots surrounded by a dark halo are likely bird excrement.  On close inspection, about 4 additional smaller spots of excrement can be seen.  I don't think these spots significantly affect the salt estimate.  The blue template was cut from poster paper.

#9     13.5 lb-----16.5 lb   per 250 sq ft   Salt swept up=0.9 oz.

#10     16.5 lb-----19.5 lb   per 250 sq ft  The image blow was enhanced to increase exposure, contrast, and sharpness.

All samples above, except #8 and #9, have no length scale, plus the precise area measured is not clearly defined.  Hence, they are not very useful.

Some dissolution by water must have occurred when the snow melted, before I arrived. Dissolution may be indicated by roundness of salt particles, seen close up, which I observed in some samples.  But I don't think a large amount of dissolution occurred, because the snowfall was light and I don't think enough meltwater accumulated to flow and remove salt from the pavement--that would be visible in a salt staining pattern.  I did see one place (photo right) where water clearly dissolved and removed most salt, leaving sharp boundaries where salt was dissolved.

Manipulation of images can improve visual comparisons

Using Photoshop or iPhone utilities can easily improve photos for visual comparisons.  To enhance, I increase the exposure a little, increase contrast a lot, and sharpen.  Most of the photos shown here (or linked to) have not been enhanced. Below is Sample #9, as taken on left, and enhanced on the right.

ImageQ presents more opportunities for image manipulation.

Comparing visual estimates to salt collected

To validate visual estimates, I collected salt at two sample locations:

• At #8, I collected 0.4 oz, or 60.0% of the amount of salt indicated by the first-choice visual estimate.
• At #9, I collected 0.9 oz. This actual salt was 105% of the salt indicated by my first-choice estimate, or 85% of the amount of salt indicated by the second-choice estimate.  Measuring more salt than estimated indicates a bad estimate.  Therefore, the second-choice estimate must be the more accurate one. This indicates of a small degree of inaccuracy in the first-choice estimate at #9--a one-step overestimation.

Given some loss of salt during collection from scattering, salt sticking to the pavement, or loss during transfers, we expect collections to weigh a bit less than visual estimations.  How much less is unknown.  The scale used for weighing samples wasn't very accurate.

Discussion

This report highlights important factors to consider when selecting sampling locations for salt.  It also provides a first test of how to visually estimate in the field (and document) the amount of salt spread.

Sampling conditions and locations

It's important to select the right location and weather when sampling.  The more that dissolution of salt by rain or meltwater has occurred, the less accurate this method will be.  Likewise, wind or traffic can disperse or entirely remove the salt before sampling.

If rain (or sufficient time) does not assure prior salt was removed, then we cannot assume we are sampling the salt applied during the last application.  However, City inspectors might only care about total salt residues, regardless of when applied.

Other factors that affect the image quality (or observing conditions and background) will have a strong but unknown effect on accuracy.  Variables likely to affect accuracy of estimation are...

1. Degree of unevenness in tone, or mottling, of the background concrete.
2. Degree of roughness.  Depressions can trap salt or create shadows.
3. Contrast of the photo.  Easily manipulated after the photo is taken.
4. Lightness/darkness of the concrete background. The darker the background, the easier it is to perceive the bright salt particles.
5. Moisture makes the concrete darker, but if the salt also appears darker, then moisture provides no visual benefit.
6. Lighting, whether diffuse or bright sun.  I don't know whether bright sun would promote more accurate estimates.  It's possible that the observer might perceive the long shadow of a salt particle as a second particle.
7. Foot or vehicle traffic grinds down particles, leading to fewer (or smaller) distinct particles, plus a lighter background (where salt dust has accumulated).

Of these variables, I suspect that #1 is the most fundamental.  All concrete is mottled.  The effect of background on accuracy of visual/photographic estimates must be tested.  Over time, as we measure the effect of each variable on accuracy, confidence in our technique of "visual estimation" of salt weights will increase.

Weight vs volume?

Any significant debris needs to be removed before measurement, especially rocks, which may appear dark.

Weight is relatively easy to measure.  Accurate digital scales cost $20-30.  If the salt is wet, that could bias the result.  If you collect salt from light-toned pavement, it's probably dry enough.  Wet salt can likely be recognized because it's probably sticky.  Wet samples could be dried, but I don't know the necessary conditions.  Letting it sit in an open container probably won't dry it, because salt attracts water from humid air.

The biggest problem with measuring volume is voids between salt particles.  The larger the particles, the larger the voids (usually).  Volume avoids the moisture issue, but volume is harder to measure accurately.  One reason is narrow containers measure more accurately, but graduated cylinders aren't usually available.  If salt is wet and sticky, it's going to be hard to transfer to/from a graduated cylinder.  Usually, the amounts of salt to measured will be small-- measures like teaspoons aren't very accurate.

Documentation

Our visual method requires documentation by photos because enforcement may follow.  The photos must be standardized--shot vertically at the same degree of enlargement, with a template to frame the exact spot.  Unfortunately, the light (direct sun or diffuse) will be hard to standardize.  Manipulation of photos in Photoshop may improve their utility.

A standard method is needed to show how each field sample location fits into the larger property, so "bias" can be estimated.  One suggestion--several overview photos of the property, with traffic cones showing where each individual sample will be taken.

As I estimated the salt at successive locations, I realized how variable each location was.  Some were still dark from moisture, others dryer and lighter in tone.  It wasn't sufficient to take a vertical photo from an unknown height.  When I looked at these photos later, I couldn't decide exactly what part of the photo I had used for my comparison to the field standard.  So these non-standard photos were useless as documentation for later analysis.

Placing a 1 square foot template around a sample (#8 & #9) proved extremely helpful for documentation.  When taking the documentation photo, just filling the camera viewfinder with the 1 ft square creates a length scale, while the template frames exactly the spot you are going to estimate, then gather salt from.  Next, the template facilitates accurate removal of the salt by sweeping. 

A template made from thin aluminum sheet would be more durable, but it cannot be allowed to curl.  The aluminum should be painted black, so reflections don't cause incorrect exposure of the photo.

Conclusions and Recommendations

Overall, these trials at 3500 University Ave. suggest that comparing a "field standard" photo of salt distribution to "field sample" plots or photos, can be accurate enough for City inspectors to use. 

These trials are a first step in developing a "protocol" for use by inspectors.  A protocol is more than a method.  It's an agreed-on series of standard steps--including documentation--that everyone must use to obtain reliable and trusted results.

Two samples, #8 and #9, are far fewer than needed to prove reliability of visual estimates.  Yet both showed a reasonably close correspondence between visual estimates and weights.  

  

It seems intuitive that images can be used to estimate salt application rates.  But "seems intuitive" is not the proof required for enforcement of salt ordinances.  The proof needed can only be provided by a series of experiments like the ones described above.

Visual estimation of salt weight/sq ft by comparing images is a form of measurement.  It's a new measurement, so it will take work to make it accurate, reliable and truly useful.  Like any kind of measurement, it must be backed up by standards, protocols, methods, and training.

This report is a firsts step in creating the required validation for a new kind of measurement.

Future Steps for Validation of Visual Estimates

Further experiments are required, because at present confidence in our accuracy is low.

• More trials indoors with salt scattered on plain gray backgrounds.  Measure how accurate comparison of field standards is to field samples.
• Trials indoors with mottled backgrounds similar to concrete.
• Trials indoors assessing how other variables degrade accuracy.
• Trials using ImageQ to create and compare "fingerprints" of salt samples.
• Trials in the field (in good weather any time of year) under varying conditions, comparing visual estimates to known amounts of salt spread.
• Develop protocols for how to handle extreme variability in salt distribution, and how to minimize bias.
• Decide on trigger level of salt for citations.
• Develop agreed on protocols for inspection of sites, and for training and regularly testing inspectors.

Why salt overuse is a persistent probem

 DRAFT        DRAFT        DRAFT        DRAFT        DRAFT

Madison, WI, has been trying to reduce the use of de-icing salt since the 1970s.  Despite many sincere efforts, application of salt by the City, plus private contractors, has continued to climb...along with the levels of salt in our lakes.

Why is it so hard to control the salt problem?  Let's try to think outside the box, looking for solutions where they may be hiding.

Problems that defy solution

There are some long-term societal problems I call "Intractible Problems," because they have defied solution for centuries.  Now, I hope readers will forgive me for speculating above my pay grade.  I'm just trying to put the salt problem in perspective.  There are some things to learn about why "problems" persist without solutions.

Drug abuse: There is increasing evidence that biology is lurking behind addiction.  Alkaloid substances like nicotine and caffein are known to be attractive to animals like bees.

But then society steps in and makes the problem a lot worse.  The management guru and author, Peter Drucker, once observed that problems like drug abuse are difficult to solve in proportion to the number of societal groups that benefit from the problem:

1. Politicians get votes by taking dramatic positions against drug addicts, peddlers, or smugglers.  This circus recently reached new heights as boats transporting drugs are being blown out of the water by the US military, using aircraft carriers and guided missiles.
2. Journalists and authors boost their careers by writing sensational articles and books.  Lobbyists play a similar role in promoting positions.
3. Law enforcement officials owe their jobs to combating drugs and stoking fear.  They often get to keep expensive assets like vehicles seized in the course of enforcement. This creates more incentives to keep promoting concern about drugs.
4. Fearful or credulous citizens continue to consume the articles, vote for the politicians, and support law enforcement, despite much evidence that current policies aren't working. Citizens may not be benefiting, but they seem to enjoy reading and hearing about the fuss and may "feel" they have benefited by voting for politicians who stoke fear.
5. Drug companies: Purdue Pharma, developed and sold OxyContin beginning in the mid‑1990s, promoting them irresponsibly, leading to widespread addiction.
6. Doctors and pharmacies profited as they continued to make prescriptions available despite obvious signs the drugs were being misused.
7. Farmers in the US benefit from growing cannabis, while Afghans grow poppies to produce heroin and Columbians grow cocaine.  Chemical companies benefit from producing precursors for fentanyl.
8. Drug pushers, smugglers, and trans-national crime gangs.  In many cases, the criminals are protected by politicians or law enforcement.

Following Drucker's lead, we see at least eight groups are in benefiting from the current ineffective approach to drugs.  I'm not saying people in all these groups want the drug problem to continue (except for those who directly profit).  What I am saying is that many groups benefit from all the noise and churn involved, while their actions support those unproductive approaches.  No wonder drugs are such an intractable problem.

Guns 

This issue is similar to drugs in that many of the same groups are involved.  Substitute manufacturers of guns for the groups that produce and push drugs.  One difference from drugs is that guns are more political.  This leads to the rise of advocacy groups like the NRA which have been extremely effective in both promoting guns and backing politicians who protect guns.

One extremely sinister aspect of the guns is that, the more fear grows from gun violence, the more people want to buy guns to protect themselves.  It's a self-reinforcing spiral leading us back to the Middle Ages.

The problem of violent crime has much in common with both drugs and guns.

What's evident when considering these most intractable problems is that fear is a driving force.

Why salt overuse is a persistent problem

I call salt a "persistent problem" because it's not "intractable" to the same degree.  It's not as ancient as drugs or guns, dating mostly from the time when we started walking and driving on pavement that could become icy.

Before salt, people sprinkled sand or "cinders" (from burning coal) on the ice.  Then we switched to salt when the sand began to clog waterway and cloud the water.  Eventually, overuse of salt has become a worldwide problem in northern climates--with reports of corroded bridges collapsing in Italy.

There aren't nearly as many groups benefiting from salt.  But there are some...

• Miners and transporters of salt or other deicers
• Manufacturers of equipment used in spreading salt
• Journalists.  Most are well behaved, excepting a few (below)
• Lobbyists: see below.
• Retailers of salt
• Trial lawyers who sue in slip/fall cases
• Contractors who spread salt on private properties
• Merchants or landlords--want to protect their customers or project a "caring" image
• Citizens benefit when they use salt to clear sidewalks, avoid lawsuits, or prevent slips on their front steps. They "feel" safer when more salt is spread in public places. Public officials are strongly influenced by complaints about slippery roads from the public. 

Note that several key actors from drugs and guns aren't big players in the salt problem.  Politicians and law enforcement are well-behaved here.

But fear of slipping on ice, and of vehicle accidents, is a real factor.  It has become axiomatic that salt makes us safer, despite evidence that oversalting has created disasters.  When roads are salted, people drive faster, counteracting the safety from salt.

Region-wide snowstorms, or multi-car collisions on highways covered by patches of black ice get a lot of attention in the news.  One of the reasons for so much attention is that pro-salt lobby groups promote stories about the benefits of salt.  

Some years ago shortly after a widespread snowstorm, many news stories appeared about the enormous economic saving to the region because preparations had been made for the storm--preparations, including of course, salt.  These stories originated with a lobby group.  Now, salt is associated with protecting commerce during the winter.

Safety vs harms of salt

This calculation of benefits vs harms is nearly impossible for stakeholders: politicians, officials, merchants, and citizens.  One reason is that the data hardly exists.  

Attempts have been made to calculate the harms from salt.  Most commonly they mention the economic cost for degradation of infrastructure.  These include corrosion of pipes, bridges, vehicles, and other infrastructure.  

It's less common, and harder, to calculate the dollar cost of harm to the environment.  These include lost recreational opportunities, the dollar value of lost fisheries, and many more harms.  These calculations are extremely difficult because of the complex interactions between species, the myriad subtle way that species can be harmed. It's also challenging to translate these harms into dollar values.

For example, recent research shows that pesticides leached into water shorten the lifespan of fish-- but do so without noticeable declines in vigor in the younger fish.  Who would have suspected such a subtle effect?  (Not salt, but it illustrates the unpredictable effects of environmental contaminants.)

Dollar values of harm are abstract and boring--they don't gain traction.  

Visible vs hidden

Everyone can see with their own eyes that a salted sidewalk is less slippery, usually. 

I was working at a heavily salted sidewalk, crouching down beside it, sweeping up salt to measure how much.  A woman came along, walking her dog.  As she approached, she scooped up her dog to protect its paws from the salt.  Preoccupied, she didn't notice me till she was very close.  Then, slowing quickly, she slipped for a moment on the loose salt before regaining her balance.

People struggle to weigh the readily visible benefits of salt against the nearly invisible harms.  Bridges and parking ramps rust from the inside.  Pre-stressed concrete beams cease to function when the steel ropes or wires inside rust.  They are very hard to inspect.  There are metods for reducing corrosion in new structures (like coating the steel elements inside with resins), but these increase costs of construction.

Failure modes of bridges and other corroded structures can be hard to predict.  When the causes of collapse are found, corrosion from salt is often just one of the causes.  When the I35W bridge in Minneapolis collapsed, there were 6 contributing causes--corrosion from salt was one.

The primary cause was a design flaw.  The designer was dead, so he couldn't defend himself.  His "sexy" design flaw was a sensation, while corrosion from salt was ignored by most people.

In Flint, MI, 99,000 people, including 55,000 children, were exposed to potential lead poisoning with overuse of salt as one of the causes.  The same disaster killed 12 of the 100 people who caught Legionnaire's disease.  The causal relationship of this outbreak to salt took so long to uncover that, again, people didn't realize salt was one of the causes.

Slow and invisible corrosion is easy to ignore. It's easy to respond to citizen complaints by spreading more salt.  As salt levels in water increase, animal populations will first lose vigor, then decline gradually.  Eventually, ecological collapse will occur when a keystone species finally succumbs to salt. All these harms take decades to unfold.

The zombie beets

Uncritical journalists sometimes contribute to the salt problem while looking for local stories with an upbeat vibe.  Enter sugar beets, stage left, to much applause.

Sugar is produced from sugar beet in a few states, including Wisconsin.  Sugar is extracted from the juice, which must then be properly disposed of because it's effectively sewage.  If dumped to waterways, juice decomposes in the water, fertilizing it (toxic algae bloom), and creating a deficit of oxygen, which leads to a fish kill.

The story that keeps rising from the grave is how some highway department experimented with beet juice they got for free--spreading it on the highway instead of salt.  And it worked!   Upbeat and clever.

What you don't hear is how the sugar producer got to dispose of sewage for free.  This story was even mentioned by a Senator at the hearings on a salt bill that I recently attended.  You are sure to hear this story at nearly every public meeting on salt.

Why beet juice will never substitute for salt...

• Pollutes the water and could kill fish by depleting oxygen
• Fertilizes the growth of algae
• Juice won't be free if the idea catches on
• There won't be nearly enough beet juice to replace salt
• Harder to transport and store than salt
• Not as effective as salt on ice

Easy solutions for difficult problems

It's just human nature:  If there's an annoying everyday problem, and someone suggests an easy solution, people are suckers.

You see it all over the internet.  "Deer eating your shrubs?  Sprinkle coyote urine about."  "Danger of collision with dear on the road? Install an ultrasonic whistle on your car.  Mice or chipmunks a problem?  Spread coyote urine, or mothballs, or cayenne pepper, essential oils, and so on.  The latest: rats chewing the electronics under the hood of your car. 

These are real problems, but the solutions aren't.  False remedies persist despite being constantly debunked by real experts.  But neighbors like to offer advice, and merchants like to make money by selling items like urine that cost very little.

People think: "I don't like coyote urine, so I'll bet the mice won't either."  People will try anything once, provided it costs less than $20 or $30.

The salt fix for snow and ice is similar.  It doesn't cost much, it's easy to use and store, everyone believes in it, and it works--sometimes.  Then there's the fear of injury to yourself, and being sued by others. Slips and falls are a real issue--but that doesn't mean salt is the only solution.

To make matters worse, some of the alternatives to salt are counter intuitive.  For example, snow and ice waste away via evaporation, even at temperatures well below freezing.  It's called "sublimation," and it can be used to speed the disappearance of ice.  Almost no one has heard of sublimation.

Because of all the quirks of human nature I've listed, kicking the salt habit is going to be difficult.  It's going to take a lot of public education.  We should focus on the various groups who contribute to the problem.

The Future

Will it be enough to just reduce levels of application of salt?

Modeling salt as we do climate change.

Mitigating the damage from salt in structures will continue.

How fast will salt dissipate if application is reduced.

Societal attitudes towards salt

Salt is considered safe because we put it on food

Salt is a pollutant in Canada but not in the US

It's hard to change human behavior

Stages of a problem (who would have thought salt could build up)?

Alternatives to applying substances to ice (another article)

Think outside of the box

Lobbying groups for salt from CoPilot

The Salt Association

A UK‑based but internationally influential industry group that represents major salt producers and promotes the use of road salt for winter maintenance. 

They publish pro‑salt messaging such as emphasizing that de‑icing salt is “non‑toxic,” “cheap,” and naturally diluted in the environment — classic industrBottom line

There is no single U.S. national “road‑salt lobby” in the way there is for oil or pharmaceuticals.

But the two groups that most clearly promote de‑icing salt use are:

The Salt Association (international, industry‑backed)

National Coalition for Open Roads (NCOR) (U.S., pro‑salt advocacy)

If you want, I can map out the major salt producers and how they influence policy, or contrast these groups with environmental organizations pushing for chloride reduction.y‑advocacy framing. 

In North America, the closest equivalent is:

The National Coalition for Open Roads (NCOR)

This group advocates for increased use of domestic road salt, arguing that salt is essential for winter safety and that up to “90% of winter accidents can be prevented with proper application.”   

Their messaging strongly aligns with industry interests.

Other groups that indirectly promote road‑salt use

These aren’t lobbying groups per se, but they support or standardize salt‑based winter maintenance:

Clear Roads Consortium

A U.S. research consortium of state DOTs that develops best practices for salt and brine use. It does not lobby, but its work supports continued salt use. 

Salt producers and distributors

Large companies in the de‑icing market (e.g., Compass Minerals, Cargill Salt, Morton Salt) often participate in trade groups or fund research, but they do not operate a single unified U.S. lobbying association.

Bottom line

There is no single U.S. national “road‑salt lobby” in the way there is for oil or pharmaceuticals.

But the two groups that most clearly promote de‑icing salt use are:

The Salt Association (international, industry‑backed)

National Coalition for Open Roads (NCOR) (U.S., pro‑salt advocacy)

If you want, I can map out the major salt producers and how they influence policy, or contrast these groups with environmental organizations pushing for chloride reduction.

De-Icing & the Environment - The Salt Association

https://saltassociation.co.uk/de-icing/de-icin  .....

www.ncfor.org

American Salt for American Roads - National Coalition for Open Roads

https://www.ncfor.org/american-salt-for-ame   ...........

Materials: Deicers - Clear Roads

https://www.clearroads.org/materials-deicers  ...............

Three disasters caused by overuse of road salt

Testimony on Salt Safety in favor of WI Senate Bill 1019 

By David H. Thompson, Ph.D.  2/17/26 

  

We think of road salt as making us safer.  But its overuse has helped cause major disasters with many lives lost.  Because salt is often only one of several causes of a disaster, salt’s deadly role goes unnoticed.  I’m going to describe how salt helped cause three disasters. 

In 2014, when Flint, MI, switched the source of its water from Lake Huron to the Flint River, salt in the city's water soared eightfold.  Salt in the Flint River came largely from de-icing salt.

 

Despite the increase in salt from the switch, to save money the city did not add a corrosion inhibitor to the water, as required by law. As a result, both iron and lead pipes in Flint corroded, causing leaks and millions of dollars in damage.  Most significantly, the corrosion exposed an estimated 99,000 residents in Flint to lead., including over 25,000 children. 

 

At the home of Lee-Ann Walters and her 3-year-old son, average lead levels were measured at levels sometimes exceeding the EPA criterion for "toxic waste."  

  

Lead poisoning was only the first blow from salt.  When iron pipes corrode, it causes a chemical reaction that destroys chlorine added to the water to kill bacteria. Without enough disinfectant in the water, Legionella bacteria multiplied in the pipes of McLaren Hospital, lining them with bacterial slime.  More than 90 people caught Legionnaire’s disease... Twelve of those people died.  

 

In Flint, excess salt was one link in a chain of cause and effect that led to 2 separate disasters.  Everyone has heard about the lead pipes.  Almost no one heard about salt's central role in the poisoning and the disease outbreak. It took a long time before the connection between Legionnaires disease and salt was demonstrated, so most people never realized salt played a role in the 12 deaths. 

 

In Minneapolis, salt contributed to the deaths of 12 people and injured 100 when the I35W bridge over the Mississippi River collapsed in 2007.  

The primary cause of the collapse was a design error that reduced the strength of the bridge.  Corrosion by salt then further reduced the structure’s strength. Rust added to the load by trapping debris and

moisture.  And rust covered bridge components so the design flaw wasn't noticed.  The final NTSB report noted four other contributing causes.

The lesson here is that millions of structures we depend on, from vehicles to bridges, are being weakened--and their safety margins reduced—because of road salt. 

 

Another salt disaster happened in the Canadian city of Elliot Lake in 2012.  The parking deck on the roof of a shopping mall collapsed, killing 2 and injuring 20.  The building had experienced decades of water and salt infiltration. A key steel beam supporting the parking roof had corroded to only 10% of its original thickness.  

 

An inquiry found systemic negligence, ignored engineering warnings, and long‑term deterioration. 

What seared Canadians was the muffled cries of trapped and dying victims, who could not be rescued for 39 hours. 

Rather than remembering the role of salt, most Canadians remember the negligence. 

 

The lesson from this event is how often salt damage is minimized and ignored.   

Overall, these events show that the damage resulting from salt overuse can be lethal because the damage is... 

• Complex, 
• Unpredictable,  
• Nearly invisible, and 
• Acting over a time scale of decades. 

 

These qualities make salt overuse both dangerous and easy to ignore. 

 

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Sources 

 

How Michigan’s Flint River came to poison a city.  The Guardian, Jan. 18, 2016. 

 

National Transportation Safety Board (NTSB). “Collapse of I‑35W Highway Bridge, Minneapolis, Minnesota, August 1, 2007.” NTSB Highway Accident Report NTSB/HAR‑08/03. Adopted: November 14, 2008. 

 

Kimberly J. Browns. 2018. The I‑35W Bridge Collapse: A Survivor’s Account of America’s Crumbling Infrastructure. Potomac Books / University of Nebraska Press.

 

CBC News, Oct. 15, 2014. Elliot Lake fatal mall collapse comes down to 'human failure,' report says.