Design Life-Cycle

Kyle Lee

Professor Cogdell, Daniel Simpson

DES 40A A07

December 2, 2021

Materials of Traffic Cones

The traffic cone is one of the most mundane objects people encounter on a common basis. Although simple in design, the extraction of materials, manufacturing, transport, and disposal of the traffic cone is a convoluted process. The materials that compose a traffic cone are part of a broader industrial production of excess toxic materials, attributable to the insufficient waste cycle of this product. This insufficient recycling process ultimately leads to needs of higher rates of raw material extraction, subsequently supplying more waste in the future. It is crucial that these toxic materials and waste are not released into the environment. This must be achieved through the innovation and implementation of green alternatives to petroleum-based plastic products, as well as the governmental policy to enact these changes for the sake of our planet.

Traffic Cones produced via PVC injection moulds are simple in their material make up. The primary base material is PVC. The two most basic materials that comprise PVC derive from salt and oil. Salt undergoes the process of electrolysis to create chlorine. While oil or natural gas is refined to create ethylene. These two secondary materials are then combined to form monomer vinyl chloride. Finally, the product undergoes polymerization to create Polyvinyl Chloride (PVC) (Patrick, 2005). The second major component of a traffic cone is the reflector band around the middle of the body. This tape is composed from polyester, acrylic, adhesive, aluminum film, and glass beads. Polyester is synthesized when polymer chips are melted and spun into filaments, which are then woven to create a strip of synthetic fabric used in the reflector tape. The production of acrylic fibers is similar to that of polyester, in which acrylic is melted down and spun into fibers (Heleno, 2002). Adhesives derive from fossil fuel resources, mainly polymers from petroleum (Packham, 2009). The two materials that attribute the traffic cone’s reflectivity are the aluminum film and the glass beads. The processing of aluminum from alumina is a simple process in which the material undergoes electrolysis and recycling (Tabereaux, 2014). Glass Beads are derived from soda, lime, and silica. That glass is then formed into small beads to reflect light (Stern, 2009). The orange pigment that gives traffic cones their distinct orange color is derived from chemicals like benzimidazolone, diketo pyrrolo pyrrole (DPP), and isoindolinone, which are commonly used in polymers like PVC (Specialchem.com, 2020). 

These materials are extracted from varying sources in order to become synthesized into one product, the traffic cone. The components of PVC are salt and oil. Although salt can be mined, the vast majority of salt production is generated through evaporation of salt water. This is done through the process of using solar heat to concentrate the seawater brine into salt crystals (Akridge, 2008). {oil part} Once the PVC is synthesized, this new material acts as a dangerous pollutant. Wastewater from the production process acts as a major threat to the aquatic environment by releasing microplastics into the oceans, while solid waste in landfills contaminate the soils with microplastics. These microplastics proliferate via the processes of weathering, UV photodegradation, and biodegradation (Meng et al., 2021). This demonstrates the volatility that an inconspicuous object like a traffic cone can play in destroying our environment. This is due to plastic products having a low recycling rate, leading much of the waste to end up in the water and soil. The toxic nature of plastic materials like PVC indicates that products derived from these components cannot create sustainable products. In order to protect the waterways and soil, innovation of sustainable alternatives must be implemented before the detriments of plastic production become unmanageable. 

The main components of the traffic cone’s reflector band are also culprits for major environmental contaminants. The base materials of the reflector bands are polyester and acrylic. The processing of polyester introduces toxic contaminants into the wastewater. Wastewater is then released into waterways, polluting the environment. Workers in these plants have also been struggling to deal with the issues with disposing of the solid sludge from these plants (Caffaro-Filho, 2009). Not only are the chemical makeup of products like polyester toxic themselves, but also the production and waste process, contaminating waterways and soil with microplastics and chemical sludge. To aid this issue, innovations of an alternative product must address both the product, but also the waste process. The dying of these plastic products also demands a lot of energy and materials, and subsequently generate a substantial amount of waste. Coloring and dying require large amounts of water, energy, and chemical dyes. Therefore, generating waste in the form of wastewater, solid waste, and gaseous emissions (Ozturk et al., 2015). This release of toxic dying chemicals further degrades the environment along with the microplastics from the PVC, polyester, and acrylic productions. 

Once the microplastic contaminated wastewater makes its way into the ocean, the plastic particles undergo a degradation process. The spread of microplastics in the ocean is a rapid one, as oceanographic models show that plastic can spread from the Eastern United States to the North Atlantic European waters in less than 60 days. The plastic industry in the US has had continuous growth for over 50 years. The global production of plastics in 2013 was 299 million tons. Landfills are the intended disposal location for plastic waste; however, a surprisingly large amount makes its way to the ocean via littering, illegal dumping, and human activity near coastal regions. In the marine environment, the material makeup of plastic particles changes the physical properties of beach sediments, and concentrate the area with concentrated contaminants like PCBs, PAHs, and organochlorine pesticides (Wang et al., 2016). This demonstrates how the plastic materials that make up traffic cones and various other plastic products is a dangerous one for the environment, and must be replaced by greener, less harmful materials.

Since the Earth cannot tolerate such pollution indefinitely, greener alternative materials for these plastics must be implemented. In terms of PVC, polyvinyl chloride’s component of DEHP has been discovered to be a possible carcinogen, disrupting the human endocrine system. Multiple more environmentally friendly alternatives have been created. One of those being aliphatic ester-derived plasticizers, which have lower cytotoxicity, are biodegradable, and are renewable (Pan et al., 2019). The search for alternative materials like aliphatic ester-derived plasticizers must be prioritized, given that a large proportion of the toxic waste generated from synthesizing these plastics are greatly dependent on the type of materials comprising the final product. Given so, by focusing on the input of green renewable materials into the production process, the output of such a system will benefit in less toxic waste emitted. Green biobased-polymers have been discovered to perform comparably to their petroleum-based counterparts, in terms of heat tolerance and elongation. Furthermore, green unsaturated polyester resins (UPRs) derived from renewable resources were found to be feasibly produced on a competitive commercial scale, as well as showing comparable or better performances in usage (Andjelkovic et al., 2009). These research studies demonstrate that the green technology is feasible and may exceed that of our current petroleum-based polymers. Given so, we should focus on prioritizing production of these more environmentally friendly materials, as so yield the rate of waste pollution from our current plastic material production processes.

Without the innovation and implementation of renewable or recyclable materials for traffic cones and other plastic based products, a feedback loop that negatively affects the environment will continue to degrade the Earth. Our current system of extracting toxic and nonrenewable materials for plastic-based products is destroying the environment via microplastics and toxic chemical waste byproducts, polluting our waterways and soils. These non-renewables will continue to pollute the environment as long as the contributing corporations do not face any penalty or consequence for doing so.  It is crucial that we urge our representatives in government to enact change and policy to regulate corporations and companies’ waste disposal, as well as incentivize the innovation and implementation of green renewable materials and products.  It is imperative that we prioritize these renewable measures before the detriment of the environment is irreversible. The traffic cone is just one of hundreds of thousands of plastic products that are quickly polluting the environment. Now that we have the practical technology through viable green renewable alternatives, we just need the policy set in place to ensure that these technologies overtake the current petroleum-based plastic production.

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Gabe Tonnos

Professor Cogdell

DES 040A

2 December 2021

Energy Relating to the Life Cycle of a Traffic Cone

Along construction zones all around the world exist traffic cones.  Everyone has seen them, but how did they get there?  Where did they come from?  How are they placed along miles of roadway seemingly overnight?  Turns out, there’s a lot more to these orange pieces of PVC than meets the eye.  Their journey from factory to footway and beyond is a lengthy one, a process that demands a fair bit of materials and energy, while leaving surprising amounts of waste behind.  Examining the life cycle of traffic cones reveals many interesting twists relating to materials, energy, and waste; however, this paper will be focusing exclusively on the energy involved in the raw materials, production, transportation, use, recycling, and disposal of the humble traffic cone.  Although the majority of traffic cones consume no energy sitting on the sidewalk, the manufacturing, shipping, and assembling of the bodies and bases of traffic cones requires lots of dirty energy, reflecting the fact that these cones are orange, not green.

Every journey has a beginning.  To find the true origin of the humble traffic cone, one must look deep into its raw materials.  The life of a traffic pylon starts several hundred feet underground in a halite mine or in the ocean.  Why?  Put simply, we need salt.  The same compound used to season food at the dinner table is absolutely essential to the fabrication of a traffic cone.  Sodium chloride (salt) is obtained either from seawater or mined halite (also known as rock salt).  Retrieving salt from seawater is quite simple, often requiring no manual energy input.  To separate the salt from the water, energy must be added to the seawater in order to convert it into a gas, leaving the salt behind.  Usually, this is accomplished through evaporation, in which all the required energy is obtained from the sun (“Salt Production”).  In halite mines, the sodium chloride is blasted or sheared straight from the earth.  The world’s largest halite mine, located eighteen hundred feet below the city of Goderich, Ontario, employs a “continuous mining” method which uses human-operated excavators (such as those used on construction sites) to scrape the salt from the rock’s face (“Our Salt Production”).  These machines typically use diesel fuel for energy, which corresponds to approximately 40 kWh of energy per gallon (Gable and Gable).  Collecting salt may not require substantial use of energy, but the next step in the life cycle of a traffic cone does.  Traffic cones are made from Polyvinyl chloride (PVC), a polymer which typically consists of fifty seven percent chlorine.  Chlorine production is “the main electricity consuming process in the chemical industry,” accomplished via electrolysis of sodium chloride, separating the chlorine gas from its molecular mate (Worrell et al.; “Polyvinyl Chloride PVC”).  The chlorine required for a single 28’’ traffic cone (7lb cone, about 4lbs chlorine) consumes on average 16.34 kWh of energy, which is the equivalent of leaving a 10W light bulb on 24/7 for over 2 months (“Welcome to JBC”; Worrell et al.)!  The remainder of the PVC is comprised of ethylene, a gas obtained by steam cracking natural gas, crude oil, or a similar hydrocarbon (all requiring significant energy to obtain), which releases a variety of gasses including ethylene.  This process requires energy-intensive heating and refrigeration efforts in order to produce and separate the ethylene gas.  Unfortunately, this means that producing one just one kilogram of ethylene (approximately the amount which is required for a standard traffic cone) requires at least 20 megajoules or 5.56 kWh of energy, which is like leaving the aforementioned light bulb on for over three weeks (“PTF: Manufacturing”)!  With the base ingredients gathered, the polymer that gives traffic cones their signature pliability and longevity is ready to be synthesized.

While gathering the raw materials for traffic cone acquisition consists of a fair bit of energy usage, creating the actual PVC and cone is a much more energy intensive task.  It is surprisingly easy to recognize how a traffic cone is manufactured solely by looking at it.  If the cone looks to be one smooth piece, it is likely manufactured using one hundred percent new PVC.  However, if the cone has a black-colored base connected to the conical section of the pylon, it is likely manufactured with new PVC for the conical section and recycled PVC for the base (“Welcome to JBC”).  Creating new PVC, which can also be found in electrical cables, window frames, packaging, and most famously, pipes, requires significant energy input (“Polyvinyl Chloride PVC”).  Just a 3-meter section of PVC sanitation pipe requires 223.4 kWh of energy to produce, which is like leaving that lightbulb on for two and a half years (Alsabri and Al-Ghamdi).  To create a traffic cone, flexible PVC pellets or powder (the form PVC is in after polymerization) is heated to up to 500 degrees fahrenheit and injection molded into the cone shape (Losek).  This is most commonly done overseas in countries such as Taiwan, where Caltrans supplier JBC Safety Plastic, Inc manufactures their cones (Wang).  Energy sources in Taiwan are skewed towards nonrenewables, with nearly half of the country’s energy derived from oil, a third from coal, and fifteen percent from natural gas.  Less than two percent of energy consumed in Taiwan is renewable, so it’s a near certainty that traffic cone production utilizes large amounts of non-renewable energy (“Bureau of Energy”).  After being synthesized and injection molded, the next stage in a traffic cone’s life cycle is shipping, an industry that uses more energy and produces more carbon than most nations (Piesing).  This will be fun.

For traffic cones manufactured overseas, they depend on an extremely cheap and dirty energy source for passage to their destination country.  Shipping uses bunker fuel for energy, which usually takes the form of a thick, black residue leftover from oil refinement.  Due to recent regulations on sulfur emissions, many shipping companies are switching ships to diesel fuel (or a mix of bunker and diesel fuels) to meet regulations (Hills).  Either way, a typical cargo ship will use between 200 and 300 tons of fuel each day (although the exact number depends on many factors such as speed and load) (“Fuel Consumption”).  The sheer amount of energy used in shipping reveals itself when focusing on a specific example.  Using the JBC cones from Taiwan as an example, the energy impact of shipping traffic cones can be evaluated.  Since shipping from Taiwan to the US west coast can take around 3 weeks, that’s approximately 4200 to 6300 tons of fuel for a one-way trip (Gronkvist)!  Based on shipping capacities of modern cargo ships, emissions of bunker fuel, and CO2 impact based on the weight of the items being shipped, it can be calculated that shipping just 4000 cones from Taiwan to Los Angeles (only 10% of what Caltrans alone purchases yearly) uses an equivalent of about 1.6 tons of bunker fuel (OOCL; “CO2 Cost”; Government Claims Program).  This amounts to 17,600 kWh of energy, which is nearly double the amount an average American house uses in a year (Fuel Oils; “Frequently Asked”)!  This amount of energy can power the 10W light bulb nonstop for over two hundred years!  For the 40,000 cones bought by Caltrans each year, shipping them uses enough energy to power the lightbulb for roughly 40% of recorded history.  Wow.  The use of such large amounts of dirty fuel for energy results in high emissions shipping.  Shipping those 4000 cones from Taiwan to California by sea can produce around 5 metric tons of carbon dioxide; that’s more CO2 than the average car pollutes in an entire year (OOCL; “Greenhouse Gas Emissions”).  Since most traffic cones are made overseas and shipped this way, the summation is massive amounts of energy and pollution for a piece of plastic that does not use any energy nor pollute during its normal use… or does it?

Surprisingly, even after gathering raw materials, synthesizing the PVC, and shipping halfway across the world, traffic cones are still using energy.  Finally, they are at the stage in their life cycle which they were created for: being placed along a construction zone, event space, or one of the countless other places traffic cones are used.  However, compared to everything that came before, any energy used from this point onwards is slight in comparison.  Traffic cones are often placed and retrieved by specialized machines or trailers using gasoline or diesel fuel for energy.  Either way, these trucks are often decades old and can have poor fuel efficiency but are faster than setting and picking up cones by hand (“Cone Machine Overview”).  When traffic cones are just sitting down on the pavement, doing their job of directing traffic, for the first time in their life cycle they are using no energy whatsoever!

Despite the durability of PVC and the rugged design of the traffic cone, they will eventually need to be retired from traffic duty.  One potential path for destroyed or worn traffic cones is disposal without recycling.  Since they are made from energy-dense PVC, the pylons are sometimes put through energy recovery processes (which can help offset the energy that was required to produce them, but not by much).  When this happens, the cones are sent to an incineration plant where they are burned with other waste and energy is generated from the heat.  However, many cones either get stolen or go straight to a landfill.  (Yarahmadi et al.; Maykuth).  While if sent to a landfill traffic cone will take centuries to decompose, they can actually offset some of their energy usage depending on how they are disposed.

Another common route for retired traffic cones is recycling.  There are two main methods of recycling materials like PVC: mechanical recycling and chemical recycling.  Due to additives often added to PVC products and its relatively high cost and energy usage, chemical recycling is not a common option for PVC waste such as battered traffic cones.  However, mechanical recycling is both practical and relatively cheap and energy efficient.  PVC can simply be minced up and remolded into a new shape.  While the recycled material is not as pure or durable as new PVC, it is still good for many uses such as for the bases of new traffic cones (Sadat-Shojai and Bakhshandeh).  Recycled PVC takes around half the energy to produce compared to new PVC, so making new cones with bases made out of recycled material is a great way to save energy as well as keep waste out of landfills (“To Recycle”).  

The life cycle of a traffic cone is a surprisingly lengthy journey. From chlorine to curbside, traffic cones use energy in nearly every stage of their existence.  With mining halite and drilling oil, energy is consumed.  With making chlorine and producing ethylene, energy is consumed.   Combining it all in an energy-intensive polymerization to synthesize one of the world’s most commonly used plastics, a process that also consumes significant energy.  Transoceanic shipping requires staggering amounts of fuel, with some pollution as a bonus!  Even placing traffic cones uses fuel and energy.  However, disposing of retired cones has the potential to recapture some energy, and recycling can help make new cones more efficient.  Clearly, there’s more to traffic cones than meets the eye in terms of energy usage throughout its life cycle.  While they might not be the most environmentally friendly or energy efficient, traffic cones help us construct the energy solutions of the future.  When we build a new solar farm, traffic cones will be there to help guide construction.  When we build wind turbines, those familiar orange pylons will be there too. Behind every row of cones lies a better world.

Thank you, traffic cones.

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Nadya Verick

Group Members: Gabe Tonnos, Kyle Lee

Professor Cogdell

DES 040A

2 December 2021

Waste and Emissions in the Life Cycle of a Traffic Cone

Traffic cones are a vital piece of road safety equipment. Originally invented in the United States, they are now used worldwide. They are relatively inexpensive to produce, and an estimated 6 million traffic cones are sold yearly in the US, with approximately 140 million in use worldwide (Safe Industrial, 2020). Their large-scale production results from a high demand for them because of their relatively short lifespan. According to Research and Markets, manufacturers claim PVC traffic cones to have a lifespan of two to three years. This isn’t even accounting for the one fifth of the yearly government purchased cones that are lost or stolen (Research and Markets, 2016). Made from Poly Vinyl Chloride thermoplastic, a durable and flexible plastic, traffic cones are injection moulded into a conical shape. PVC injection moulded traffic cones produce waste and emission throughout every stage of their life cycle, including toxic fumes from production and recycling at the end of its two-to-three-year lifespan, emissions from transportation, and waste buildup in outside of their recycling from the percentage of missing cones each year (Creative Mechanisms, 2016). 

It is important to examine the impacts of traffic cone production because they are such a necessary piece of equipment. The cones themselves as a concept are irreplaceable, but the materials and processes used to create them are not. There has been a lot of research into improving traffic cones in their function, such as making them more durable and heat resistant, hence the thermoplastic. It is only relatively recently that people have put thought into making them out of materials that are less toxic and more easily recyclable. The sheer bulk of the plastic that makes up the cones that go missing each year, presumably to end up in a landfill somewhere, is nothing to sneeze at. If one cannot focus on extending the longevity of a product that only has an estimated lifespan of 3 years, it is time to shift in a new direction to save resources and reduce waste. 

One of the most dangerous and alarming byproducts from PVC cones is Hydrogen Chloride gas (HCl) which is produced when the cones are injection moulded. Poly vinyl chloride (PVC) is a type of plastic that is made from chlorine. When used to make traffic cones, additives to make the plastic more flexible and heat resistant are mixed in (Creative Mechanisms, 2016).  That PVC is then injection moulded, which is a process that involves melting plastic and injecting it into a specialized mould. The Moulds are kept at a low temperature to help cool the plastic as fast as possible. When injection moulding, PVC must be heated to a high temperature to melt, usually between 140o to 160o C. At around 150oC, it starts to release HCl gas, a gas that is incredibly toxic to humans. The process produces much higher amounts when it reaches above 180oC, which it sometimes can (Lau, 2019). HCl can erode the cavities of the moulds because of how corrosive it is (Shaw, p. 2). As a result, the moulds must be cleansed frequently, which creates contaminated water (Lau, 2019).  This gas is easily the most dangerous waste byproduct during production.

That isn’t to say that the factory machines themselves don’t create large amounts of waste. When making a product that requires such high temperatures, the machines that make them need to burn a lot of fossil fuels to create that much heat. Even after production, traffic cones metaphorically and literally still have a long way to go in their life cycles. 

The next stage in the traffic cone life cycle is transportation and shipping. Cones are produced in factories and shipped to buyers. They take up a lot of space and are heavy in large quantities. If it is assumed that they are being produced in another country such as China, the transportation to the United States would most likely take place by cargo ship. Cargo ships produce an impressive amount of CO2 and other greenhouse gas emissions. Container ships produce approximately 140 million metric tons of CO2 a year (Statista, 2020). That isn’t even including other greenhouse gases such as nitrous oxide (NOx) and sulphur oxide (SOx), toxic chemicals linked to acid rain. They also create non gas pollution like human waste and spilled oil that damages ocean ecosystems (Heckstall, 2018). Once they reach the shores of their destination, they then have to be shipped over land to buyers. 

Land transportation becomes necessary when production is domestic or to move product from port sites. Freight trucks, usually pulled by semis, are the main way product is transported over land. The amount of emissions depends on how much weight is being hauled and how far it’s being moved. Freight trucks emit 161.8 grams of CO2 per ton-mile on average. The maximum load weight for a freight truck is 80,000 pounds, which is about 36.3 metric tons (Freight Management and Operations, 2015). Shipping from a port like Matson in Oakland, to Davis California, would be about 70 total miles of distance. This results in approximately 411133.8 grams of CO2 or 0.42 tons of CO2. Freight trucks can sometimes travel thousands of miles before delivering products. That is a lot of greenhouse gases. Once organizations receive the cones, more trucks pick up where the freight trucks leave off. 

One of the biggest issues facing government bodies like Caltrans that use traffic cones is the placement and retrieval of said cones at construction sites. One method involves driving slowly in a light duty Caltrans cone body truck and having a worker place cones down by hand as they receive them from a conveyor belt (AHMCT, 2010). Most light duty Caltrans trucks are modified Ford F250s (Caltrans, 2021). These vehicles have a 20 mile per gallon average, which is relatively inefficient and creates a lot of greenhouse emissions. The other method of placement and retrieval is through the Cone Placement and Retrieval Vehicle, a specialized piece of equipment meant to place and retrieve traffic cones automatically (AHMCT, 2010). The equipment is essentially a much heavier modified conventional vehicle such as a Ford or GMC truck and does not achieve any better gas mileage than placing the cones by hand. In fact, the added machinery most likely makes the vehicle less fuel efficient and increases CO2 emissions. The cones will live the rest of their short lives being placed, retrieved, and moved until it is time for them to be recycled.

When taken at face value, the recyclability of flexible PVC seems like a green solution to the plastic waste problem, but minor investigations into the subject prove otherwise. Firstly, PVC as a material is not easy to recycle. All of the additives at the beginning of its creation to make it flexible and thermoresistant are hard to separate from the plastic. Oftentimes when it is recycled, it is turned into inferior products like wire insulation (Ecolife, 2011). While traffic cones can be fully produced from recycled vinyl, they often aren’t entirely composed of such materials (Mikofalvy, p. 162). The thicker, heavier, lower quality plastic bases of traffic cones are often made from recycled material, and the springier orange parts are made from new PVC. Cones not turned into bases find themselves turned into a variety of other low-quality products, but those that escape do not have a much better time. 

According to Markets and Research, up to one fifth of all government purchased cones go missing every year. On average, Caltrans buys about 41,000 traffic cones a year (Caltrans, 2021). That’s an estimated 8,200 cones lost or stolen every year in California. That is about 81,000 pounds of PVC thermoplastic that just disappears. Most likely the cones make their way to landfills, but the average person has probably run into a stray cone littered in an area it shouldn’t be. Litter like that has an impact on the immediately surrounding environment and ecosystem. 

Researching this unfortunately necessary product has revealed a not-so-green truth to those little orange cones. They are made from a plastic that takes centuries to decompose, and producing them creates not only emissions, but toxic fumes. They must be shipped from every production facility, shipping being another necessary evil in the current consumerist culture. They are ultimately difficult to recycle and can only be made into further inferior products. Even if they are fully recycled, the finite resources in fossil fuels and the waste that they create is forced into an already unstable circle. There is also little research into finding an alternative to the current materials and methods used specifically for traffic cones. While there is existing research, it is unlikely that PVC will be replaced anywhere in the near future for their manufacturing. Just as with many other products, if the methods and materials aren’t changed, neither will the eventual waste be reduced. Toxic, wasteful, and inefficient, the life cycle of the traffic cone has little more to offer than the depressing reality depicted in the life cycle analysis of any other plastic products. 

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