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Litter is one of the more notably neglected and yet obvious forms of environmental blight. Addressing this problem is a challenge because it is not perceived as a crisis issue compared with other environmental problems.

By Steven R. Stein and Kristian C. Ferguson

Historical as well as recent attitude surveys show that many Americans view litter as a minor offense and continue to deliberately toss refuse—including cigarette butts and organic waste (e.g. apple cores)—onto the roadsides. However, data suggest that more than half of the litter observed along roadways may well come from sources other than deliberate litterers.

While some drivers continue to deliberately throw trash out of their vehicles—commonly referred to as intentional litter—others carelessly drive around in improperly secured vehicles with any number of items waiting to fall out when hitting a pothole, taking a curve too fast, or traveling at a high rate of speed, creating unintentional litter.

The consequences of unintentional litter can be dire. More than 25,000 accidents occur in the US each year with unintentional litter and road debris as the primary cause resulting in significant damage to people and property—damage that can be prevented, in part, by properly securing a vehicle’s load.

In California alone last year, traffic accidents caused by road debris were responsible for 155 deaths, according to the California Department of Transportation (CalTrans). Due in part to these statistics, determining the sources of roadside litter and debris has become an important issue for transportation departments and solid waste managers alike.

According to a recent report by the American Automobile Association (AAA) Foundation for Traffic Safety, 77% of state highway departments remove vehicle-related road debris (VRRD) from multilane roads daily. The top five types of VRRD that highway maintenance staff cited when asked which were the most prevalent in their jurisdictions are: tire treads (84%); garbage from waste haulers (50%); lumber and construction materials (39%); gravel, soil, and tree limbs that were being transported (32%); and mufflers and exhaust parts (26%).

Tire treads on the roadside (also known as “road alligators”) account for over three-quarters of VRRD and usually occur when tires are not properly inflated or otherwise maintained improperly, causing a buildup of heat intense enough to separate the tread from the tire. For every loss in air pressure of 2 pounds per square inch, tire temperature will increase five degrees, increasing the probability of a blowout.

Litter Though the Years
Although management issues regarding the efficient collection and disposal of garbage have existed throughout history, the problems with litter as we know it were fueled by the Industrial Revolution and the development of modern cities, resulting in refuse and garbage tossed in the streets.

Litter can become a significant problem downstream. Runoff from roads and highways can block stormwater inlets, filling harbors and bays with floating debris.

City street departments and health officials struggled to deal with the problems caused by this open dumping. Municipal responsibility for street cleaning was in place in 70% of the cities by 1880, but the litter problem, for the most part, continued unabated.

New York City attempted to address this problem in 1899, when city staff recommended curbside collection of refuse and garbage. In 1915, Boston experienced such unrestrained littering in the streets that the street cleaners could not keep up. Cities had adopted anti-littering ordinances, but they were deemed unenforceable, and police were accused of indifference. Various initiatives were tried, but were subject to state and municipal financial constraints.

The end of World War II meant the end of a conservation ethic that had accompanied the war. The birth of a national highway system in the 1950s provided automobile drivers with the opportunity to toss their refuse and garbage out of their car windows onto the vast stretches of roadways. The profile of litter in the 1950s and 1960s seemed homogenous and predictable; however, it has changed over the past 20 years. Compounding population growth has only made this problem worse.

Although the issues of litter continue to be a challenge, history suggests that progress has been achieved in addressing this problem.

Intentionally Characterizing Litter
Litter can be characterized as disposed materials that are unlawfully abandoned and non-containerized, a characterization that can easily include a vast number of items, from cigarette butts and bottle caps to newspapers and vehicle debris.

To categorize the numerous items defined as litter, litter surveyors count and analyze litter and debris on roadsides to determine the probable sources and extent of litter, similar to the solid waste quantification and characterization studies conducted at the behest of communities.

To determine these sources, each observed item of litter greater than 1 inch in diameter is categorized as either intentionally littered or unintentionally littered. Intentional litter is defined as materials or products that are usually seen thrown or otherwise deliberately left behind intentionally in inappropriate locations.

Unintentional litter is defined as material or products that are usually discarded passively (such as vehicle debris from accidents), materials that fall from improperly secured vehicles, or items that fall out of unsecured vehicles. It also includes items that spill from overloaded or tipped trash cans and items dropped or left behind unintentionally.

There are some instances where an item that is usually considered intentionally littered, might be unintentionally littered and vice-versa.

Categories of litter, intentional or unintentional, can be described by a methodology developed by the National Academy of Sciences for a 1968 national litter survey and later adopted and expanded by the Institute for Applied Research (IAR). The objective of this study was to analyze the types and quantity of litter found on our nation’s highways and other roadways.

Intentional litter identified in the study included: beer and soft drink beverage containers; other beverage containers (tea, sports drink, water, etc.); bottle caps and seals; pull tabs; beverage carriers and cartons; cups, lids, and straws; snack food packaging; fast-food packaging; tobacco packaging (cigarette packs, lighters, and matches); paper napkins, bags, and tissues; toiletries; toys; medicine; and cigarette butts.

The unintentional litter included: newspapers, magazines, and books; advertising signs and cards; home food packaging (e.g., TV dinners); vehicle debris and packaging; construction and demolition debris; miscellaneous paper; miscellaneous plastic; miscellaneous metal and foil; miscellaneous glass and ceramics; wood and yard debris; and other debris (e.g., carpet or fabric).

Analyzing Years of Litter
One of the major issues involving litter assessment is the determination of whether an item was likely to have been littered intentionally or unintentionally.

The business consulting firm of R.W. Beck was retained by Keep America Beautiful to review all major litter surveys and related analysis that had been conducted since 1990.

In addition, R.W. Beck evaluated certain landmark surveys that had been conducted between 1968 and 1978 for baseline comparisons.

Many of the litter surveys conducted used similar product categories. The review was undertaken, in part, to characterize the percent of litter that was unintentional as compared to intentional.

Figure 1 shows the breakdown between the two categories of litter, starting with data for the pre-1986 surveys and following through the Tennessee 2006 survey. The trend suggests an increase in unintentional litter, as opposed to intentional or deliberate litter.

A group of 31 litter surveys that had been conducted by the IAR in 1986 found that nearly 65% of litter was intentional while only 35% was unintentional. Beginning in 1990, some surveys began to show a change in this trend. The 1990 Louisiana survey results showed slightly more intentional litter (51%) than unintentional (49%).

A litter survey conducted in Kentucky in 1998 demonstrated a reduction in the percent of intentional litter from 74% to 54% when comparing changes in Kentucky’s litter from the base year of 1980, which supports the theory of increasing unintentional litter.

In addition to the changes in suspected sources of litter (unintentional versus intentional), there is evidence that littering as a whole has dropped, according to a report issued by the IAR in 2006 comparing the litter rate for 62 surveys that had been conducted over the last 30 years. The report concluded that the rate of litter (items per mile) has been trending downward at an average rate of about 2% per year.

When data regarding the amount of litter found on roadsides is viewed as a whole, litter reductions may not be as apparent. When these data are broken out between those items that are intentional and unintentional litter, the reduction in intentional litter is more evident, as illustrated in Figure 1.

Unintentional Transformation of Litter
Surveys conducted by R. W. Beck in 2006 in both Georgia and Tennessee noted an increase in unintentional litter over previous surveys conducted in other states. The major components of unintentional litter in Georgia and Tennessee included miscellaneous paper and plastic, the type of materials that might fall off improperly secured loads.

Vehicles transporting trash and construction debris are known sources of this kind of unintentional litter. The addition of vehicles collecting curbside recyclables nationwide has meant a larger number of collection vehicles that may be unintentionally littering America’s roads. This has become more of a problem as a number of curbside recycling programs have been put in place since 1990. From a handful of programs, curbside recycling has now become a mainstay in thousands of American communities.

While these programs have successfully diverted a significant amount of material from landfills, they have also created additional vehicles collecting materials from the same residential and commercial areas. To the extent that trash vehicles have contributed to the unintentional spillage of trash, recycling vehicles have now increased the opportunity for such spillage—especially miscellaneous paper and plastic products.

The recent AAA study noted that 50% of highway departments reported spillage from trash and recycling vehicles as a cause of roadside litter.

A Shift in Focus on Litter
The drop in overall litter rates along with an increase in unintentional litter over the past 15 years suggests that litter education and cleanup efforts—such as the Keep America Beautiful and Adopt-a-Highway programs—may have been successful in reducing intentional litter. However, unintentional litter should now be an important focus in the future to achieve further reductions in litter.

What is the extent of the litter problem? Texas estimated in 2005 that there were nearly 27 million pounds of litter on Texas roadways, while Ohio, in 2004, estimated nearly 24 million pounds of litter on its roadways—both emphasizing the extent of litter that many states are facing. And this problem is not limited just to the states.

Research conducted by R.W. Beck suggests that cities and counties are spending more to clean up roadside litter than the states themselves spend. R.W. Beck has determined that cities, counties, and states spend an estimated $1–$3 per person for litter-related costs each year in addition to the costs incurred by such volunteer groups as Keep America Beautiful and Adopt-A-Highway. Litter cleanups represent the most expensive form of waste management, costing hundreds of dollars per ton to clean up from our roadsides. According to PA CleanWays, Pennsylvania spends an average of $800 per ton to clean up the heavily littered sites in that state.

Steven R. Stein is senior consultant and litter analyst for R.W. Beck. Kristian C. Ferguson served as field manager on R.W. Beck litter surveys in Georgia and Tennessee.

MSW - November/December 2007