Car harm: A global review of automobility's harm to people and the environment is a paper that was recently published in the Journal of Transportation Geography. This paper covers, on a global scale, many of the negative externalities presented by widespread car reliance. The authors neatly summarize these externalities within different categories, in a way such that this can be used for a framework of analysis for specific cities. This piece will cover many of these categories of harm, and show how they apply to car dependency in Louisville. Some categories heavily overlap or have little data, so they may be merged into each other.


Crashes are the most well-known form of car-related violence. Car crash data in Louisville is available dating back to 2014, with major injuries and deaths being tracked by Vision Zero Louisville. All numbers from Vision Zero should also include intentional car violence in addition to accidents. 

Since 2016, major injuries from cars have ticked down while total deaths have increased. According to census data, in 2022, around 83.7% of workers in Jefferson County commuted to work by car in some form. This percentage represents approximately 391,000 people. Averaging the non-pedestrian crash data, 544 of these people will be seriously injured or killed on the road every year. This is on top of the thousands of crashes with minor injuries and the many that go unreported.

Air, Land, and Water Pollution

Many people only think of exhaust emissions when thinking of the pollution given off by cars, but their actual polluting effect is much more extensive. Car production itself is a carbon-intensive process, and Louisville is home to two vehicle plants. Both of these plants are registered Title V facilities, meaning they are permitted to emit more than 100,000 tons of carbon dioxide equivalent greenhouse gas emissions. 2020 data shows these plants were producing around 132,202 tons of carbon dioxide, making these plants some of the top polluters in the county not dedicated to electrical generation. 

As soon as the vehicles are on the road, they are producing a variety of pollutants that affect the surrounding land, air, and water.  All vehicle thoroughfares will have higher levels of pollution, but expressways are generally considered to have a “danger zone” of 500 feet where there are high levels of pollution. Some regulators even suggest avoiding sites within 1000 feet of expressways. The Envirome Institute’s Greenheart Project exists partially to help mitigate emissions like this, which is especially important when an estimated 67,000 people live within 1000 feet of an expressway in Jefferson County.

Both the 500 foot and 1000 foot zones have important facilities within their bounds. Elder care facilities, schools, and hospitals lie well within 500 feet. Downtown is particularly afflicted, with the convergence of multiple expressways at Spaghetti Junction. A perfect example of this is where I-65 crosses Muhammad Ali Blvd; An elementary school, the school playground and UofL Hospital are right next to I-65.

In addition to the widely known exhaust emissions, brake pads, tires, clutches, and other parts produce microplastic, particulate, and heavy metal pollution. Car tires alone have been found to produce 78% of microplastics in the ocean and 3-7% of all particulate matter in the air. While there is limited research on this in Jefferson County, it is safe to assume a good amount of microplastics are littering our air and waterways. Particulates, microplastics, and heavy metals are all linked to a wide variety of cognitive, cardiovascular, respiratory, and other illnesses that can cause lifelong disabilities and premature death.

Noise Pollution

Noise pollution produced by cars primarily comes from their engines at lower speeds and their tires at higher speeds. Sound dilutes much quicker than gas emissions, at least, so distance from major roadways can help in reducing the negative health effects caused by noise pollution. Tinnitus, hearing loss, and cognitive impairment are some of the common health effects of consistent exposure to noise pollution. Louisville has a good amount of sound barriers on its expressways, but this is largely in suburban areas.

While noise pollution from cars is a major concern in Louisville, the largest source of noise pollution comes from the Airport. This is reflected when you map the average decibel level throughout the county. Depending on where you live, like parts of Old Louisville for example, you may be forced to deal with the combined noise pollution of a nearby expressway, other car traffic, freight trains, and airplanes. Outside of the urban core, large arterial roads such as Taylorsville Road consistently expose nearby residents to noise pollution from fast-moving vehicles.

Light and Thermal Pollution

While light pollution is difficult to measure on a county level (at least only car-related light pollution), thermal pollution is a well-known issue within Jefferson County. Car-dependency has largely dictated land use patterns, creating an incredible amount of impervious surfaces (paved areas) that retain heat and increase urban ambient temperature via the urban heat island effect. Until recently, Louisville had the fastest growing urban heat island in the country. Even now, we still rank pretty high. Below is a map of heat hot spots in Louisville based on the ratio of greenery to impervious surfaces. Click here to view the map below in its own window.

Urban heat can be deadly for vulnerable populations, such as the elderly. Poorer populations who do not have access to air conditioning can also face health issues such as heat stroke, heat exhaustion, and breathing problems.

Sedentary Travel and Time

Car travel is inherently the most sedentary form of transit, most people just have to walk to their driveway or garage, and get on their way. Sedentary lifestyle has been linked to an increased risk of mortality through cardiovascular issues, cancer, type two diabetes, and many other health issues. With 84% of Louisville commuting by car, the vast majority of the city has a sedentary commute. Data indicates the average commute time in the city is around 22 minutes, so locals are spending an average of 44 minutes a day sitting in their car.

Even if the sedentary nature of cars were not a factor, car travel is one of the greatest consumers of time. The graph above shows how much time Louisvillians spend on commuting alone, this does not include how much time people are forced to spend in cars doing errands, going to events, or looking for parking. A study by AAA in 2019 showed that the average American spends around 17,600 minutes a year driving. This is equivalent to seven forty hour work weeks.

Dependence and Isolation

Auto-centric infrastructure and urban design can be a significant contributor to social isolation. This is because places where socializing occurs begin to warp into “islands” that you must drive to access. Under this paradigm, you are unlikely to have a chance encounter with a friend that you may have while walking. This is why many people fondly remember their time in college. You could walk most places and easily encounter and hang out with your friends; something that becomes more difficult after graduation for many. 

This isolation issue can be even worse for those who don’t own a car. They may struggle to get to the social “islands”, and become isolated from their friends and community.

This isolation can be especially relevant for children. Children used to overwhelmingly get to school by foot, bus, or bike, but this began to shift in the 1990s. Now, most students get to school by private vehicle. This harms children in terms of social isolation, with less opportunities for unplanned outdoor play and being reliant on parents to get to most social events. Children are also at risk for the same negative sedentary effects as adults, which can possibly affect them going into adulthood.

Unequal Distribution of Harm

Car harm does not distribute itself equitably on a global scale. The Car Harm paper points out how poorer countries and neighborhoods with larger minority populations tend to experience more vehicle violence. On top of this, car safety features are largely designed with women in mind. This leads to more injuries and deaths for women compared to men when in major accidents. 

In Louisville, accessible crash data shows that more men were killed or suffered serious injuries in car accidents. This is not conclusively showing Louisville bucking the trend, though, as there is not enough information about those involved in the accidents to know if this is related to driving patterns or vehicle design. There is a pretty large disparity in where crashes are occurring, though, with neighborhoods that have higher minority populations generally having the most collisions.


Prevalence of car-focused infrastructure creates barriers for those not in cars. Parking meters, parked cars, and safety posts often reduce space dedicated to pedestrians. This can be especially problematic for the disabled, as they may be forced into the road with cars to navigate around these things. What pedestrian facilities do exist, may not be implemented well.

Walk sign at 7th and Hill

Lack of alternative transit options also plays a major role in creating accessibility issues. Micromobility and public transit can be difficult to utilize with a lack of infrastructure or long wait times respectively. Infrastructure like bike lanes can also be utilized by disabled residents and help with accessibility, but Louisville’s current network is pretty limited; there are only around 60 miles of bike lanes and most of them are either unprotected or underutilized.

Taylorsville Road in J-Town: features a clutterd sidewalk and small, unprotected bike lane

Car-Dependent Places

Much of Louisville is designed around car use. This has resulted in a sprawled-out, inefficient land use pattern that is difficult to move across without a car. Even the urban core of Louisville has much of its land dedicated to car use in some form. This all contributes to increasing the urban heat island effect, and much of this land (especially parking) sits empty most hours of the day.

The area in red is land primarily dedicated to the automobile

Much of the city outside of 264 features large commercial and suburban developments like the one below. This development style features fields of parking accompanying big box stores that are almost entirely visited by people in cars. The amount of people that can walk (if they even feel safe doing so) is limited, as nearby housing is primarily zoned exclusively for single family homes; around 75% of the county is zoned exclusively for single-family homes. 

Taylorsville Road and Hurstbourne Parkway

Outside of car dependence, this also leads to issues with affordability. Single-family homes inherently lack density so you can only build so many before you run out of space or start encroaching on nature, increasing land cost. These homes are also more expensive to build per-residence than multi-family units, so the cost to rent or own is usually higher.

Financial Burden

Personal vehicles are not cheap to buy or to maintain. AAA conducts yearly studies on the cost of car ownership, and the most recent one indicated the yearly average cost of car ownership is $12,182. Part shortages have only seen this number increase in recent years. All of the externalities listed above can have personal costs as well that are not included: hospital bills after a car crash, medical treatment for illnesses caused by pollution, and so on.

Outside of personal costs, there is a large societal financial cost. Governments, one way or another, have to pay for the externalities introduced by car dependence. Everything listed so far from exhaust emissions to social isolation can cost you money in one way or another. Land-use patterns facilitated by car dependence can be especially costly. Car-dependent suburbs are very costly to maintain, and often don’t produce enough in taxes to cover their own costs. This leads to rich suburbs of many cities actually being subsidized by the poorer, urban areas.

Tax Revenue by Census Block

Car harm: A global review of automobility's harm to people and the environment provides an extensive framework that shows how cars can harm us. Reliance on cars has come at the expense of our personal and public health. The paper also presents many solutions that we have talked about here at the Urban Design Studio before: embracing micromobility, reducing traffic speeds, constructing complete streets, etc. The current paradigm does not have to be the norm for Louisville, or for any city. All of these alternatives can provide a path to a much healthier city.