In the US, transit deserts are making it hard for people to find jobs and stay healthy

Many Americans need reliable public transit to get to school or work. Image: Frank Hank/creative commons.

As any commuter who has experienced unreliable service or lives miles away from a bus stop will tell you, sometimes public transit isn’t really a viable option, even in major cities.

In our car-loving society, where 85 per cent of Americans use a car to get to work, people who cannot access transportation are excluded from their own communities and trapped inside “transit deserts.” This term, which one of us (Junfeng Jiao) coined, describes areas in a city where demand for transit is high but supply is low.

Lack of transit has harmful effects on those who rely on public transit – generally, people who are too young, too old, too poor or have disabilities that don’t allow them to drive. Mapping these deserts will help agencies adjust transit services and better serve their communities.

At UT Austin’s Urban Information Lab, our research focuses on refining the methods used to quantify and measure transit supply and demand. We’ve developed clear and concise geographic information system (GIS) methods to evaluate transportation systems, providing alternatives to previous, more complicated network modeling. These methods can quickly be applied to any location, as we have shown in studies of five major cities in Texas and other cities across the United States. By using this method, we found that hundreds of thousands of transit-dependent people in Texas don’t have access to mass transit systems.

Connecting people to jobs and services

Research shows that low-income residents living in sprawling areas have limited transportation options, which constrains their job opportunities and upward mobility. Inadequate transportation keeps people from finding work, which then reduces the productivity of their communities. It also can limit access to medical services, causing health problems to go undetected or worsen.

Addressing transit access is one important strategy for tackling broader social problems. For example, welfare recipients are less likely to own cars or have access to transit than the general population. Reducing these transportation barriers would help move them from welfare to work.

In cities with well-developed infrastructure for cycling, such as Amsterdam, large shares of the population commute by bicycle. Image: Steven Lek/author provided.

Although scholars have been studying “food deserts” (areas where residents lack access to nutritious food) for several decades, we have only recently applied this logic to mass transportation systems, despite the fact that food deserts often occur due to lack of transportation.

Relatively little research has been carried out to identify and quantify gaps between transit demand and supply. But as counties and cities feel the effects of declining funding from federal and state transportation user fees, they need new ways to target transportation infrastructure investments and ensure limited resources are used in the best way possible. We have found that maps are a promising way to guide these discussions.

Mapping transit deserts

Determining exactly who relies on mass transit can be difficult. Existing information depends on census data. As previously noted, people who rely on transit are usually from marginalised demographic groups. They may be elderly, poor or have disabilities that keep them from driving. Census data do not account for the fact that sometimes these populations overlap (a transit-dependent person could be old as well as poor), so one individual could be counted many times.

Also, census data on car ownership are not available at the census block group level, which is the smallest geographic unit published by the U.S. Census Bureau. This lack of data makes it hard to measure transit dependency with accuracy.

Measuring transit supply is easier. It relies on data from municipal planning agencies as well as relevant municipal and county GIS departments, which manage spatial and geographic information, analysis tools and mapping products. These agencies measure variables that include numbers of transit stops, transit routes and frequency of service, as well as lengths of sidewalks, bicycle lanes and low speed-limit routes (which are relevant because some commuters may opt to walk instead of taking the bus).

Beyond city centers

Current research shows that transit deserts exist all over the country. Cities such as Chicago; Cincinnati; Charlotte, North Carolina; Portland, Oregon; and San Antonio contain multiple communities that don’t have enough transit services to meet existing demand. Even in older cities, where development tends to follow transit lines, there are neighborhoods where the supply of transit is simply not enough.

This is a large-scale problem. In San Antonio, the seventh-largest U.S. city by population, some 334,530 people – nearly one-fourth of the population – need access to public transportation in a city that doesn’t even have rail service. In Chicago, where there are high levels of transit dependency all across the city, just three of the transit desert neighborhoods that we identified house approximately 176,806 residents. Even in a city as progressive as Portland, Oregon, thousands live in transit desert neighborhoods.

Transit desert analysis for the city of San Antonio. Negative numbers connote areas where demand for transit exceeds supply. Image: author provided.

When it comes to geographic location, transit demand and supply appear to follow certain spatial patterns. Unsurprisingly, transit supply is highest in city centers and decreases as distance from city centers increases. As a result, transit deserts do not typically occur in city centers or near downtown. In fact, because of the typical “hub and spoke” design of many transit services, city centers often have transit surpluses where supply outstrips demand.

The location of transit deserts often does not follow a geographic pattern, although they are usually associated with low-income and remote areas. While planners and engineers may have a rough idea of where supply is low, making service adjustments requires measuring and mapping of transit supply and demand citywide.

Rebalancing transit networks

Many cities are now making service adjustments to improve service to transit deserts. For example, Houston’s transit authority, METRO, recently redesigned its bus service as part of a larger “Transit Service Reimagining,” in an attempt to better meet the region’s mobility needs. Evaluation of the new transit services shows that current levels of transit demand and supply are more balanced, though gaps still exist.

Identifying transit deserts is even catching on at the federal level. The U.S. Department of Transportation recently launched a new initiative to map transit deserts nationally through a National Transit Map, which will put together data from different transit agencies into a complete feed. By accessing a larger, national look at transit demand and supply, regional agencies will have extra tools available to them when making changes to their local transit services.

What these changes will be is hard to say. Expanding existing bus services may be the most cost-effective way to improve transit access. Even in New York City, with its massive subway system, city officials are increasingly turning to bus rapid transit due to the high cost of adding new subway lines.

Adding bus lines, increasing service hours and even streamlining boarding and fares can help improve service and increase access. Integrating bicycling with transit services would be another cost-effective option.

The ConversationAs research on transit deserts continues to grow, more precise methods of quantifying the gap between transit supply and demand should develop. More research may provide new views on how the built environment and socioeconomic variables affect transportation accessibility. With careful planning and investment, these transit deserts can eventually transform into transit oases.

Junfeng Jiao is assistant professor of community & regional planning and director of the Urban Information Lab, and Nicole McGrath an MS candidate in community & regional planning, at University of Texas at Austin.

This article was originally published on The Conversation. Read the original article.


The IPPC report on the melting ice caps makes for terrifying reading

A Greeland iceberg, 2007. Image: Getty.

Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) – the UN body responsible for communicating the science of climate breakdown – released its long-awaited Special Report on the Ocean and Cryosphere in a Changing Climate.

Based on almost 7,000 peer-reviewed research articles, the report is a cutting-edge crash course in how human-caused climate breakdown is changing our ice and oceans and what it means for humanity and the living planet. In a nutshell, the news isn’t good.

Cryosphere in decline

Most of us rarely come into contact with the cryosphere, but it is a critical part of our climate system. The term refers to the frozen parts of our planet – the great ice sheets of Greenland and Antarctica, the icebergs that break off and drift in the oceans, the glaciers on our high mountain ranges, our winter snow, the ice on lakes and the polar oceans, and the frozen ground in much of the Arctic landscape called permafrost.

The cryosphere is shrinking. Snow cover is reducing, glaciers and ice sheets are melting and permafrost is thawing. We’ve known this for most of my 25-year career, but the report highlights that melting is accelerating, with potentially disastrous consequences for humanity and marine and high mountain ecosystems.

At the moment, we’re on track to lose more than half of all the permafrost by the end of the century. Thousands of roads and buildings sit on this frozen soil – and their foundations are slowly transitioning to mud. Permafrost also stores almost twice the amount of carbon as is present in the atmosphere. While increased plant growth may be able to offset some of the release of carbon from newly thawed soils, much will be released to the atmosphere, significantly accelerating the pace of global heating.

Sea ice is declining rapidly, and an ice-free Arctic ocean will become a regular summer occurrence as things stand. Indigenous peoples who live in the Arctic are already having to change how they hunt and travel, and some coastal communities are already planning for relocation. Populations of seals, walruses, polar bears, whales and other mammals and sea birds who depend on the ice may crash if sea ice is regularly absent. And as water in its bright-white solid form is much more effective at reflecting heat from the sun, its rapid loss is also accelerating global heating.

Glaciers are also melting. If emissions continue on their current trajectory, smaller glaciers will shrink by more than 80 per cent by the end of the century. This retreat will place increasing strain on the hundreds of millions of people globally who rely on glaciers for water, agriculture, and power. Dangerous landslides, avalanches, rockfalls and floods will become increasingly normal in mountain areas.

Rising oceans, rising problems

All this melting ice means that sea levels are rising. While seas rose globally by around 15cm during the 20th century, they’re now rising more than twice as fast –- and this rate is accelerating.

Thanks to research from myself and others, we now better understand how Antarctica and Greenland’s ice sheets interact with the oceans. As a result, the latest report has upgraded its long-term estimates for how much sea level is expected to rise. Uncertainties still remain, but we’re headed for a rise of between 60 and 110cm by 2100.

Of course, sea level isn’t static. Intense rainfall and cyclones – themselves exacerbated by climate breakdown – can cause water to surge metres above the normal level. The IPCC’s report is very clear: these extreme storm surges we used to expect once per century will now be expected every year by mid-century. In addition to rapidly curbing emissions, we must invest millions to protect at-risk coastal and low-lying areas from flooding and loss of life.

Ocean ecosystems

Up to now, the ocean has taken up more than 90 per cent of the excess heat in the global climate system. Warming to date has already reduced the mixing between water layers and, as a consequence, has reduced the supply of oxygen and nutrients for marine life. By 2100 the ocean will take up five to seven times more heat than it has done in the past 50 years if we don’t change our emissions trajectory. Marine heatwaves are also projected to be more intense, last longer and occur 50 times more often. To top it off, the ocean is becoming more acidic as it continues to absorb a proportion of the carbon dioxide we emit.

Collectively, these pressures place marine life across the globe under unprecedented threat. Some species may move to new waters, but others less able to adapt will decline or even die out. This could cause major problems for communities that depend on local seafood. As it stands, coral reefs – beautiful ecosystems that support thousands of species – will be nearly totally wiped out by the end of the century.

Between the lines

While the document makes some striking statements, it is actually relatively conservative with its conclusions – perhaps because it had to be approved by the 195 nations that ratify the IPCC’s reports. Right now, I would expect that sea level rise and ice melt will occur faster than the report predicts. Ten years ago, I might have said the opposite. But the latest science is painting an increasingly grave picture for the future of our oceans and cryosphere – particularly if we carry on with “business as usual”.

The difference between 1.5°C and 2°C of heating is especially important for the icy poles, which warm much faster than the global average. At 1.5°C of warming, the probability of an ice-free September in the Arctic ocean is one in 100. But at 2°C, we’d expect to see this happening about one-third of the time. Rising sea levels, ocean warming and acidification, melting glaciers, and permafrost also will also happen faster – and with it, the risks to humanity and the living planet increase. It’s up to us and the leaders we choose to stem the rising tide of climate and ecological breakdown.

Mark Brandon, Professor of Polar Oceanography, The Open University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.