Urban Sprawl/Traffic

This chapter will introduce you to Urban Sprawl, how it's changed the urban landscape, and how it's still evolving.

Introduction

Urban Sprawl is the rapid, low density growth of urban areas with little or no regard to urban planning. This growth is usually unrestricted and could be within the housing, commercial, or transportation sectors. Waves of urban sprawl have occurred in the United States several times since the introduction of motorized transportation, and have correlated strongly with changes in automobile development and use. This module will highlight these waves of sprawl, focusing on the period between 1950 and 2020.

Urban Sprawl

Urban Sprawl: Which U.S. City Sprawls the Most?

First Wave of Urban Sprawl

John Adams, the geographer not either of the U.S. presidents, determined that most people generally prefer to live within 30 minutes of their place of work, and their mode of transportation will determine the distance they can live from that location. Prior to the introduction of streetcars, walking, and horses or horse drawn carriages were the only modes of transportation in cities, so this limited the radius in which people could live within the city. The introduction of electric streetcars in the late 1880s expanded the 30-minute radius and allowed people to move further away from the central part of the city where most businesses were located. This migration to the outskirts of the city became the first wave of urban migration and defined the structural layout of the city by creating the first concentric ring of housing around the city. This  article  from the Smithsonian’s National Museum of American history describes the introduction and life of streetcars in Washington, D.C. It also includes several historic images and photographs of early streetcars.

Stages of Intraurban Growth (from DeBlij and Muller, 2014).

Second Wave of Urban Sprawl

The second wave of urban sprawl began with the introduction of large-scale automobile production in the 1920s-1930s. Robust arterial roads were constructed to connect the central city to new, residential, single-family housing that was being developed along the outskirts of the city. The additional space allowed for larger lot sizes and yards, creating a pattern of decreasing density with increasing distance from the city center. This also created a new ring around the existing ring of housing around the city.

Third Wave of Urban Sprawl

The third wave of urban sprawl is the most extensive and began after World War II with the introduction of interstates and large highways/freeways encircling the city. American affluence increased after the war and large-scale automobile production shifted back to consumers after years of being utilized for military production. Vehicle construction had also become more advanced and with the lower costs of materials that came with the war’s end, the automobile industry expanded. Automobiles were no longer luxuries, but affordable necessities for the expanding suburbs, prompting a new wave of sprawl further outside of the city.

By 1960, 80% of city dwellers had at least one car, with the percentage of multi-car households steadily increasing into the 21st  century . The convenience of large highways encircling the city allowed for another increase in the 30-minute radius as commuters could access the highways from a number of entryways and exits. New neighborhoods encompassed larger lot sizes than those constructed during the previous wave of sprawl, and were developed further away from the city center, creating a pattern of concentric zones.

Urban development Concentric Zones. (https://simple.wikipedia.org/wiki/Concentric_zone_model; https://en.wikipedia.org/wiki/Concentric_zone_model)

The period between 1950 and 1990 saw rapid suburban expansion. Increased commercial development occurred in areas surrounding suburbs transforming suburbs into separate, distinct cities. These edge cities redefined the urban landscape by creating metropolitan regions that extend beyond the traditional city limits, and replaced the concentric ring model of urban development with a more complex multi-city agglomeration.

Urban Realms Model depicting Edge Cities (from DeBlij and Muller, 2014).

Because urban sprawl is unregulated, by the 1990s, sprawling cities were creating gridlock commutes for suburbanites, along with greater air pollution from the increased vehicle emissions. To combat this, cities expanded arterial highways and larger beltways to add more lanes, where possible. Most American cities also designated high occupancy vehicle (HOV) lanes to their main beltways to promote ridesharing. During the morning and afternoon “rush hour” commute times (varies by city and state), HOV lanes are only to be used by motorcycle riders and automobiles that are transporting a minimum of two people. Emergency vehicles are also allowed to use these lanes.

HOV lane in Atlanta, Georgia. (https://en.wikipedia.org/wiki/File:AtlantaHOVlane.jpg)

In some cities with high congestion, smaller, arterial roads will switch direction with the morning and afternoon commutes. In other words, these reversible lanes will accommodate more traffic going into the city during the morning commute and more traffic leaving the city during the afternoon/evening commute. Traffic lights overhanging these lanes will indicate a green arrow if you’re going in the right direction at that time or a red X if you’re not.

With a high population density, the Washington, D.C. metropolitan area is one of the most congested urban areas in the U.S. Thousands of people commute into D.C. from the neighboring states of Maryland and Virginia. Maryland has several arterial roads entering the city that use this method to maximize lane use. In the 1990s, Maryland also expanded their metro and rail lines going into Baltimore and Washington D.C. by extending existing lines further away from the city centers, adding more stops, and connecting more lines together.

Reversible lane in Silver Spring, Maryland. (https://www.montgomerycountymd.gov/DOT-TMC/Control/getlus.html)

Los Angeles, California

Los Angeles is another one of the most densely populated and traffic congested cities in the United States. One hundred years of urban sprawl has created a multi-centered, car-dependent city with expansive freeways and endless construction that hasn't lessened congestion. The city has been implementing various measures to minimize congestion since the early 2000s. In 2002, the L.A. Metro introduced the EZPass, a regional transit pass. Within the next few years, Google Maps and the Waze App were relaying immediate traffic conditions to commuters, allowing them to plan alternative routes at times of heavy congestion.

Urban Realms of Metropolitan Los Angeles (from DeBlij and Muller, 2014).

In 2012, L.A. Metro began transitioning some of the HOV lanes into express toll lanes. Other congestion fees include facility tolls on freeways and bridges that are imposed during specific days and times, zone tolls for vehicles traveling through specific areas within the city limits, and cordon tolls for vehicles crossing specific boundaries. An additional corridor toll has been proposed for specific sections of freeways that experience high levels of congestion.

Los Angeles is also expanding their metro and light rail lines, and by 2010, had begun several projects. The Expo light rail line, which runs for 15 miles from downtown Los Angeles to Santa Monica, was completed in 2016. Expansion to the Crenshaw line is underway to LAX airport, and expansion of the Purple line along Wilshire Boulevard to Beverly Hills should be completed in 2023. Additional transit projects are also underway with plans to be ready in time for Los Angeles to host the 2028  Olympics .

Another solution to eliminating traffic congestion is by staying home. Enhanced information technology like Google Maps and Waze allow people to plan trips accordingly when possible. The stay-at-home order implemented in March 2020 provided an opportunity to see the increased flow of traffic as many Angelinos began working from home. A report by the Texas A&M Transportation Institute indicated that Los Angeles experienced such a change in traffic during the coronavirus pandemic that it experienced less congestion than New York City in 2020 for the first time  since 1982 . In 2020, Los Angeles also produced less than half the amount of greenhouse gases produced in 2019. Many people who began working from home during the pandemic have continued to do so, and encouraging more people to work from home will not only further reduce traffic congestion, but it will also minimize air pollution and greenhouse gas emissions.

Atlanta, Georgia

American Makeover Episode 1: Sprawlanta

Although sprawl began to decline in many American cities by the beginning of the 21st century through gentrification and an increase in high density housing, cities with a lot of surrounding rural areas have continued to sprawl further away from the city center into these hinterlands. Sometimes this even results in the loss of small farms that can’t keep up with the rising property taxes and declining profits. Atlanta is one of these cities and experienced one of the highest population growth rates (15%) between 2010 and 2020, and has continued to sprawl. You can watch a time lapse of Atlanta's sprawl from 1984 to 2016  here .

Urban Sprawl reaches Rural Georgia

Atlanta is the 9th most populated metropolitan area in the United States and the largest metropolitan area in the southeast with a population that has been steadily increasing since the second wave of urban sprawl began in 1950. Its population has now surpassed 6 million and projections indicate that it could reach  8.5 million by 2050 .

Atlanta’s extensive urban sprawl has resulted in a very car dependent city. The rapid growth has created heavy congestion during peak traffic times. Atlanta is rated the 4th worst congested city in the U.S. A  2019 study  found that Atlanta drivers spend 64 hours each year in traffic on the downtown Connector, which was rated as the 5th most  congested corridor in the U.S . The intersection of I-85 and I-285 (aka. The Spaghetti Junction) is one of the worst bottlenecks in the U.S. Overall, the average commuter in Atlanta spends 70 hours per year in traffic.With population growth expected to continue, Atlanta needs to implement solutions to the growing traffic problem.

Stretch of highway along the I-75/I-85 corridor known as The Connector. ( https://commons.wikimedia.org/wiki/File:Atlanta_75.85.jpg )

The Metropolitan Atlanta Rapid Transit Authority (MARTA) is the largest public transportation provider in Atlanta and maintains buses, trains, and streetcars. MARTA operates 38 train stations and 338 rail cars, over 550 buses, and 173 lift vans. It also operates the existing streetcar loop in downtown Atlanta.

Hop On MARTA!

Between 2014-2015, MARTA upgraded their bus fleet with 200 new fuel-efficient buses, and has reduced emissions by 95% in over half of their buses. They also partnered with the Atlanta streetcar to provide last mile service to downtown locations. In 2016, Atlanta passed a new half penny sales tax that will generate $2.5 billion over the next 40 years to expand existing rail and bus services and add more stops. There are also plans for additional streetcars to increase connectivity to the BeltLine (more on that below).

Streetcar in downtown Atlanta, pulling up to the King Memorial stop, 2017. ( https://commons.wikimedia.org/wiki/File:Atlanta_Streetcar_arriving_at_King_Memorial_Stop.jpg )

Atlanta has a high volume of commercial vehicle use and is planning to introduce a designated commercial vehicle only lane along a stretch of I-75 in an effort to maintain a steadier flow of traffic. The designated lane will use new technology to produce live updates of traffic conditions that can be sent directly to commercial vehicle drivers during their commutes. Although this project isn’t scheduled to begin until 2026, Atlanta is currently testing the technology along a stretch of North Avenue that includes the headquarters for Coca-Cola and AT&T and the Georgia Department of Transportation.

The BeltLine is a long-term project that Atlanta began working on in 2005. The plan is to revitalize a 22-mile loop of former rail lines into a multi-use trail in an effort to increase connectivity within the city. In doing so, it’s connecting neighborhoods throughout the city and creating the ability for residents to live and work within a walking (or biking) distance, as more apartments (i.e. higher density housing) are constructed along the loop. The 30-minute radius of pedestrian travel is becoming re-embraced as the 21st century brings a different demographic of city dwellers with different desires from those a century ago. The  BeltLine plans  also support the capability of installing multiple streetcars throughout the loop as well as some crisscrossing between different areas along the loop. This will further increase the 30-minute radius from home to work with the faster transit time the streetcar will bring. The loop is also connecting several parks in the city, while several sections along the loop are also being left as greenspaces. Additional trails are being constructed from various neighborhoods to the loop. By 2012, 11 miles had been completed. Here is the  full timeline  for the BeltLine project.

Teleworking, or working remotely from home, is another potential solution for Atlanta’s traffic congestion. Since 2019, some Atlanta companies have had employees work from home one day each week or have employees start work later after the morning rush hour has passed. The result is several thousand less people commuting in Atlanta during peak rush hour times.  Projections indicate  there would be 9,000 less cars in traffic if 50% of workers in the Atlanta district worked from home one day each week. Prior to the coronavirus pandemic, it was estimated that 15% of district employees worked from home at least some of the time. The increased flow of traffic that occurred during the stay-at-home orders caused many Atlanta officials, employers, and commuters to rethink the traditional work schedule. Now, even more people throughout the Atlanta metro are working remotely part of the time.

Summary

Cities have evolved over time to accommodate their populations. Prompted by advances in transportation, the 20th century saw areal expansion of cities as people moved further away from the city center. Early streetcars allowed people to move further away from their workplace while still maintaining a 30-minute commute, but cars allowed people to move even further away from the city center. By mid-century, car ownership was common and suburbanization was underway. By the end of the 20th century, population growth, multi-car families, and urban sprawl had created severe traffic congestion and a massive increase in commute times for suburbanites. The 21st century has seen a renewed interest in living closer to city centers to avoid the traffic and long commute times that urban sprawl has created. This has also caused people to seek other modes of transportation besides automobiles. As such, cities throughout the world are working to become less dependent on automobiles leaving many to question if we have reached the  age of “peak car” . Regardless, cities are reclaiming roads and parking lots and becoming more pedestrian and bicycle friendly to accommodate their 21st century populations.

Additional Reading

https://www.theguardian.com/cities/2016/jul/12/urban-sprawl-how-cities-grow-change-sustainability-urban-age

References

Adams, J.S. 1969. Directional Bias in Intra-Urban Migration. Economic Geography. 45:302-323.

DeBlij and Muller, Geography: Realms, Regions, and Concepts 16th Edition, John Wiley and Sons, 2014.

U.S. Census Bureau -  http://www.census.gov 

https://inrix.com/press-releases/scorecard-2018-us/

https://gacommuteoptions.com/home/return-to-office/covid-19-commute-impact-report/

Stages of Intraurban Growth (from DeBlij and Muller, 2014).

Urban development Concentric Zones. (https://simple.wikipedia.org/wiki/Concentric_zone_model; https://en.wikipedia.org/wiki/Concentric_zone_model)

Urban Realms Model depicting Edge Cities (from DeBlij and Muller, 2014).

HOV lane in Atlanta, Georgia. (https://en.wikipedia.org/wiki/File:AtlantaHOVlane.jpg)

Reversible lane in Silver Spring, Maryland. (https://www.montgomerycountymd.gov/DOT-TMC/Control/getlus.html)

Urban Realms of Metropolitan Los Angeles (from DeBlij and Muller, 2014).

Stretch of highway along the I-75/I-85 corridor known as The Connector. ( https://commons.wikimedia.org/wiki/File:Atlanta_75.85.jpg )

Streetcar in downtown Atlanta, pulling up to the King Memorial stop, 2017. ( https://commons.wikimedia.org/wiki/File:Atlanta_Streetcar_arriving_at_King_Memorial_Stop.jpg )