Construction of Interstate 95, downtown Richmond (2899336022)

Road expansion refers to the increasing rate at which roads are being constructed globally. Increases in population size and

GDP Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is ofte ...

, particularly in

developing nations A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...

, are the primary drivers of road expansion but

transportation planning Transportation planning is the process of defining future policies, goals, investments, and spatial planning designs to prepare for future needs to move people and goods to destinations. As practiced today, it is a collaborative process that i ...

decisions also play an important role. The anticipated length of newly paved roads to be built between 2010 and 2050 would encircle the planet more than 600 times.Laurance, W.F., Clements, G.R., Sloan, S., O'Connell, C.S., Mueller, N.D., Goosem, M., Venter, O., Edwards, D.P., Phalan, B., Balmford, A., et al. (2014). A global strategy for road building. ''Nature'' 513, 229–232 Approximately 90% of the new roads are being built in developing nations.

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

are predicted to have a large amount of road expansion in the near future. Roads facilitate access to

markets Market is a term used to describe concepts such as: * Market (economics), system in which parties engage in transactions according to supply and demand * Market economy *Marketplace, a physical marketplace or public market Geography *Märket, a ...

, health services and education but may adversely affect the

natural environment The natural environment or natural world encompasses all life, living and non-living things occurring nature, naturally, meaning in this case not Artificiality, artificial. The term is most often applied to the Earth or some parts of Earth. Th ...

, and impact communities and economies. There is also disagreement on whether expanding and widening congested roadways truly relieves traffic congestion.

Effects on the environment

Road infrastructure expansion can have numerous impacts on environmental systems. Road construction and use can serve as a significant source of mortality for wildlife.Laurance, W.F., Goosem, M., Laurance, S.G.W., 2009. Impacts of roads and linear clearings on tropical forests. Trends in Ecology & Evolution 24, 659–669.Trombulak, S.C., Frissell, C.A., 2000. Review of ecological effects of roads on terrestrial and aquatic communities. Conservation Biology 14, 18–30. Roads can affect animal movements either by acting as a barrier or allowing easier movement.Forman, R.T.T., and Alexander, L.E. (1998). Roads and their major ecological effects. Annual Review of Ecology and Systematics ''29'', 207–231.Laurance, W.F., Croes, B.M., Tchignoumba, L., Lahm, S.A., Alonso, A., Lee, M.E., Campbell, P., Ondzeano, C., 2006a. Impacts of roads and hunting on Central African rainforest mammals. Conservation Biology 20, 1251–1261.Blake, S., Deem, S.L., Strindberg, S., Maisels, F., Momont, L., Isia, I.-B., Douglas-Hamilton, I., Karesh, W.B., Kock, M.D., 2008. Roadless wilderness area determines forest elephant movements in the Congo Basin. PLoS ONE 3, e3546.

Habitat fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...

by road expansion can impact the movement and

migration Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...

of species, as well as breeding and

genetic structure Genetic structure refers to any pattern in the genetic makeup of individuals within a population. Genetic structure allows for information about an individual to be inferred from other members of the same population. In trivial terms, all popul ...

.Laurance, W.F., Croes, B.M., Guissouegou, N., Buij, R., Dethier, M., Alonso, A., 2008. Impacts of roads, hunting, and habitat alteration on nocturnal mammals in African rainforests. Conservation Biology 22, 721–732.Clements, G.R., Lynam, A.J., Gaveau, D., Yap, W.L., Lhota, S., Goosem, M., Laurance, S., Laurance, W.F., 2014. Where and how are roads endangering mammals in Southeast Asia's Forests? PLoS ONE 9, e115376. Fragmentation also produces edge effects that alter the

microclimate A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few squ ...

and

ecological succession Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less. Bacteria allows for the cycling of nutrients such as ca ...

of habitat patches.Laurance, W.F., Camargo, J.L.C., Luizão, R.C.C., Laurance, S.G., Pimm, S.L., Bruna, E.M., Stouffer, P.C., Williamson, G.B., Benítez-Malvido, J., Vasconcelos, H.L., Van Houtan, K.S., Zartman, C.E., Boyle, S.A., Didham, R.K., Andrade, A., Lovejoy, T.E., 2011. The fate of Amazonian forest fragments: a 32-year investigation. Biological Conservation 144, 56–67.Laurance, W.F., Laurance, S.G., Ferreira, L.V., Rankin-de Merona, J.M., Gascon, C., Lovejoy, T.E., 1997. Biomass collapse in Amazonian forest fragments. Science 278, 1117–1118.Laurance, W.F., Lovejoy, T.E., Vasconcelos, H.L., Bruna, E.M., Didham, R.K., Stouffer, P.C., Gascon, C., Bierregaard, R.O., Laurance, S.G., Sampaio, E., 2002b. Ecosystem decay of Amazonian forest fragments: a 22-year investigation. Conservation Biology 16, 605–618.

Exploitation

Road expansion increases the accessibility to previously intact ecosystems, allowing for increased rates of ( over-)

exploitation of natural resources The exploitation of natural resources is the use of natural resources for economic growth, sometimes with a negative connotation of accompanying environmental degradation. It started to emerge on an industrial scale in the 19th century as the ex ...

through

hunting Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...

, and

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

.Gaveau, D.L.A., Sloan, S., Molidena, M., Husnayanem, Wijaya, A., Ancrenaz, M., Nasi, R., Wielaard, N., and Meijaard, E. (2014). Four decades of forest loss and degradation in Borneo. PLoS ONE ''9'', e101654.Wilkie, D., Shaw, E., Rotberg, F., Morelli, G., and Auzel, P. (2000). Roads, Development, and Conservation in the Congo Basin. Conservation Biology ''14'', 1614–1622. These activities, along with fires and conversion of forest to other land uses are major causes of

tropical forest Tropical forests (a.k.a. jungle) are forested landscapes in tropical regions: ''i.e.'' land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds. Some tropical fores ...

loss across the globe.Laurance, W. F., Campbell, M. J., Alamgir, M., & Mahmoud, M. I. (2017c). Road expansion and the fate of africa's tropical forests. ''Frontiers in Ecology and Evolution, 5'' (75), 1–7. doi:10.3389/fevo.2017.00075Laurance, W.F., Cochrane, M.A., Bergen, S., Fearnside, P.M., Delamônica, P., Barber, C., D'Angelo, S., Fernandes, T., 2001a. The future of the Brazilian Amazon. Science 291, 438–439.Laurance, W.F., Sayer, J., Cassman, K.G., 2014b. Agricultural expansion and its impacts on tropical nature. Trends in Ecology & Evolution 29, 107–116. Road expansion increases

deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...

through increased access to previously inaccessible forests, facilitating unofficial road building, legal and

illegal logging Illegal logging is the harvest, transportation, purchase or sale of timber in violation of laws. The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a pro ...

, illegal colonization of previously undisturbed areas,

land speculation In finance, speculation is the purchase of an asset (a commodity, goods, or real estate) with the hope that it will become more valuable shortly. (It can also refer to short sales in which the speculator hopes for a decline in value.) Many s ...

land grabbing Land grabbing is the contentious issue of large-scale land acquisitions: the buying or leasing of large pieces of land by domestic and transnational companies, governments, and individuals. While used broadly throughout history, land grabbing as ...

, and forest conversion through illegal and legal means.Kirby, K.R., Laurance, W.F., Albernaz, A.K., Schroth, G., Fearnside, P.M., Bergen, S., Venticinque, E.M., da Costa, C., 2006. The future of deforestation in the Brazilian Amazon. Futures 38, 432–453.Laurance, W.F., Albernaz, A.K.M., Schroth, G., Fearnside, P.M., Bergen, S., Venticinque, E.M., Da Costa, C., 2002a. Predictors of deforestation in the Brazilian Amazon. Journal of Biogeography 29, 737–748. A strong positive correlation has been observed between road building and deforestation in regions such as

the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

, and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

.Laurance, W.F., Sloan, S., Weng, L., Sayer, J.A., 2015b. Estimating the environmental costs of Africa's massive "Development Corridors". Current Biology 25, 3202–3208. Around 95% of all deforestation in European countries has occurred within 5.5 km of legal or illegal roads, indicating a strong association of existing and planned roads as a proximate driver of forest loss and degradation. Road expansion also facilitates increased access for

hunters Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, et ...

and

poachers Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...

,Maisels, F., Strindberg, S., Blake, S., Wittemyer, G., Hart, J., Williamson, E.A., Aba'a, R., Abitsi, G., Ambahe, R.D., Amsini, F., Bakabana, P.C., Hicks, T.C., Bayogo, R.E., Bechem, M., Beyers, R.L., Bezangoye, A.N., Boundja, P., Bout, N., Akou, M.E., Bene, L.B., Fosso, B., Greengrass, E., Grossmann, F., Ikamba-Nkulu, C., Ilambu, O., Inogwabini, B.-I., Iyenguet, F., Kiminou, F., Kokangoye, M., Kujirakwinja, D., Latour, S., Liengola, I., Mackaya, Q., Madidi, J., Madzoke, B., Makoumbou, C., Malanda, G.-A., Malonga, R., Mbani, O., Mbendzo, V.A., Ambassa, E., Ekinde, A., Mihindou, Y., Morgan, B.J., Motsaba, P., Moukala, G., Mounguengui, A., Mowawa, B.S., Ndzai, C., Nixon, S., Nkumu, P., Nzolani, F., Pintea, L., Plumptre, A., Rainey, H., de Semboli, B.B., Serckx, A., Stokes, E., Turkalo, A., Vanleeuwe, H., Vosper, A., Warren, Y., 2013. Devastating decline of forest Elephants in Central Africa. PLoS ONE 8, e59469.Blake, S., Strindberg, S., Boudjan, P., Makombo, C., Bila-Isia, I., Ilambu, O., Grossmann, F., Bene-Bene, L., de Semboli, B., Mbenzo, V., S'Hwa, D., Bayogo, R., Williamson, L., Fay, M., Hart, J., Maisels, F., 2007. Forest elephant crisis in the Congo Basin. PLOS Biology 5, e111. leading to an increase in legal and illegal

. In Central Africa, the strongest predictors of decline in elephant populations were proximity to expanding infrastructure and absence of law enforcement. A significant decline in

African forest elephant The African forest elephant (''Loxodonta cyclotis'') is one of the two living African elephant species. It is native to humid forests in West Africa and the Congo Basin. It is the smallest of the three living elephant species, reaching a should ...

populations between 2002 and 2011 was facilitated by increased road-building rates in Central Africa. In equatorial West Africa, the collapse of

gorilla Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus ''Gorilla'' is divided into two species: the eastern gorilla and the western gorilla, and either four or fi ...

and

chimpanzee The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...

populations was primarily caused by hunting that was spurred by a rapid expansion of road networks, which facilitated poaching as well as habitat conversion.Sloan, S., Supriatna, J., Campbell, M.J., Alamgir, M.., Laurance, W.F. (2018). Newly discovered orangutan species requires urgent habitat protection Current Biology. Walsh, P.D., Abernethy, K.A., Bermejo, M., Beyers, R., De Wachter, P., Akou, M.E., Huijbregts, B., Mambounga, D.I., Toham, A.K., Kilbourn, A.M., et al. (2003). Catastrophic ape decline in western equatorial Africa. Nature ''422'', 611–614. Where forest management is weak, road expansion proceeds unregulated, and can be allowed to fragment crucial

bioregion A bioregion is an ecologically and geographically defined area that is smaller than a biogeographic realm, but larger than an ecoregion or an ecosystem, in the World Wide Fund for Nature classification scheme. There is also an attempt to use the ...

s and protected areas. In Africa, upgraded and proposed road-development corridors intersected 345 protected areas, of which 69 were high value protected areas (

national park A national park is a nature park, natural park in use for conservation (ethic), conservation purposes, created and protected by national governments. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state dec ...

World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...

Ramsar site A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention,8 ha (O) *** Permanent 8 ha (P) *** Seasonal Intermittent < 8 ha(Ts) **

Effects on the economy

Market access

Road infrastructure development lowers the cost of accessing markets, especially for remote communities. Increased

market access In international trade, market access is a company's ability to enter a foreign market by selling its goods and services in another country. Market access is not the same as free trade, because market access is normally subject to conditions or req ...

allows producers, such as farmers, to increase the export of their goods, and thereby increase the flow of money into the community. Improved road infrastructure has reduced poverty by facilitating higher production and exports in Peru, Bangladesh,Khandker, S., xa, R, Bakht, Z., Koolwal, G., xa, & B. (2009). The Poverty Impact of Rural Roads: Evidence from Bangladesh. ''Economic Development and Cultural Change, 57''(4), 685-722. doi:10.1086/598765 and parts of Sub-Saharan Africa. Improved market access as a result of improved road infrastructure facilitates a shift from

subsistence agriculture Subsistence agriculture occurs when farmers grow food crops to meet the needs of themselves and their families on smallholdings. Subsistence agriculturalists target farm output for survival and for mostly local requirements, with little or no su ...

to increasingly specialized and commercialized agriculture. Increased commercialization of agriculture results in economic gains for communities, however it can also increase dependence on external markets and external sources of goods. This has been shown to either result in improved

food security Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World F ...

, as communities are not reliant on their own agricultural capacity, or be detrimental to nutritional status as communities no longer produce a diverse range of crops. Facilitating access of remote communities to urban markets can also have the effect of allowing urban market influences to affect rural economies. In the

Democratic Republic of the Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

, urban markets are subject to greater control by soldiers than are rural markets, resulting in hunters and farmers paying more

protection money A protection racket is a type of racket and a scheme of organized crime perpetrated by a potentially hazardous organized crime group that generally guarantees protection outside the sanction of the law to another entity or individual from viol ...

and getting less of a share of profits made. Greater market intensity is in some instances environmentally detrimental. In the Democratic Republic of the Congo, more large-bodied and endangered animals are hunted for sale in urban markets than in rural markets.

Road construction

Roads must be well designed and constructed to reduce impacts on regional

geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...

and

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...

. In undulating terrain, road construction typically proceeds via cut-and-fill activities, in which high parts of the landscape are cut down and the fill (soil and mineral earth) is

bulldozed A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous tracks, ...

into lower areas, in order to flatten-out the topography along the road route. Concurrently,

vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic character ...

is usually cleared along and adjacent to a road footprint. These practices dramatically increases surface

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

and sediment inputs to water courses, altering hydrological patterns, reducing

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

for

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s and livestock and elevating water turbidity and

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

.Sidle, R.C., Ziegler, A.D., 2012. The dilemma of mountain roads. Nature Geosci 5, 437–438. The altered existing hydrological dynamics resulting from cut and fill activities, inadequate drainage, culverts, and bridges associated with road construction can also obstruct surface-water flow, leading to impeded drainage and localized flooding, particularly during high-rainfall episodes. Road construction in mountainous areas or steep terrain increases the risks of

landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated grade (slope), slope failures, mudflows, and debris flows. Landslides occur in a variety of ...

s, particularly in wet environments. Site disturbances, vegetation clearing, unstable terrain caused by cut-and-fill activities, and road drainage all contributes to the elevated rates of landslides in mountainous or steep terrain areas with roads 8 with the likelihood of landslides in close proximity to roads being up to five times higher. In the Brazilian Amazon, ~90% of fires occurred within ≤10 km of roads. Road construction in forests leads to an increased frequency of fires. This happens via numerous mechanisms, including intentionally lit fires (leading to

), leaked fires from land management practices adjacent to fragmented forests or roads, and accidental fires due to increased human-ignition sources. Increased fire frequency results directly in biomass loss and

carbon emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and larg ...

, and elevated fire regimes alter the

species composition Species richness is the number of different species represented in an community (ecology), ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the Abundance (ecology), abunda ...

and ecological dynamics of susceptible forests.

Traffic and road maintenance

Funding for new road infrastructure in developing nations is focused on initial road construction, with less money being earmarked for ongoing maintenance.Alamgir, M., Campbell, M.J., Sloan, S., Goosem, M., Clements, G.R., Mahmoud, M.I., Laurance, W.F., 2017. Economic, socio-political and environmental risks of road development in the tropics. Current Biology 27, R1130-R1140. With many new roads being constructed in high-rainfall tropical environments, degradation leading to slumping and pot-holing is rendering expensive paved roads impassable in just a few years. Road degradation increases the cost of using the road, by lengthening travel time or causing damage to vehicles. Poor quality paved roads may cost less on initial construction, but are more costly to maintain and produce greater costs of use over the life of the road. Maintaining roads involves long-term and major investments which are subjected to

corrupt Corruption is a form of dishonesty or a criminal offense which is undertaken by a person or an organization which is entrusted in a position of authority, in order to acquire illicit benefits or abuse power for one's personal gain. Corruption m ...

practices of those responsible for maintenance. Moreover, budgeting high construction costs, but building substandard roads which require higher levels of maintenance are both common practice and a major drain on public expenditure and private investment. Such activities escalate costs and reduce the usable lifetime of roads, and are particularly evident in many developing countries where corruption is more pervasive and implicitly tolerated.Mahmoud, M. I., Sloan, S., Campbell, M. J., Alamgir, M., Imong, I., Odigha, O., . . . Laurance, W. F. (2017). Alternative routes for a proposed nigerian superhighway to limit damage to rare ecosystems and wildlife. ''Tropical Conservation Science, 10'', 1940082917709274.World Bank. (2010). ''Cost-benefit analysis in world bank projects''. Retrieved from Washington, DC Increased road expansion incentivizes people to purchase cars and use roads to a greater extent. This results in further degradation of the roads, leading to higher maintenance costs. Increased use of vehicles and roads leads to more accidents, particularly in regions where roads are of poor quality and motor vehicle use is relatively novel. More roads result in more traffic, due to

induced demand In economics, induced demand – related to latent demand and generated demandSchneider, Benjamin (September 6, 2018"CityLab University: Induced Demand"''CityLab'' – is the phenomenon whereby an increase in supply results in a decline ...

, further increasing the rate of road degradation. As such, economic appraisals of road projects in developing countries often find that improving existing road infrastructure is more beneficial than construction of new road infrastructure.

Effects on societies

Access to services

In developing countries especially, goods and services such as health facilities and educational facilities are often concentrated in urban regions, with little to no availability in remote and rural areas. Road expansion provides greater accessibility to urban centers, and hence improves educational attainment. In both

Bangladesh Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...

and

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

investments in improving rural roads have led to greater education attainment. Similarly, greater access to urban areas gives remote communities better access to health facilities, including

medical supplies A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assur ...

and medical information, and has been associated with better health outcomes. Access to urban centers facilitated by road expansion improves employment opportunities. In Indonesia, improved roads allowed job creation in manufacturing industries and an occupational shift amongst workers away from agriculture. Conversely, a greater supply of people seeking employment can drive down the wages in an area, producing a negative effect on livelihoods.Grant, U. (2008) Opportunity and exploitation in urban labour markets London: Overseas Development Institute While access to goods and services associated with urban centers is beneficial, increased relocation to already densely populated centers increases the strain on cities already struggling to cope with growing populations, particularly in developing regions. Increasing urbanization presents problems including increased crime, increasing inequality, and public health concerns.

Migration and culture

Road expansion leads to

forced migration Forced displacement (also forced migration) is an involuntary or coerced movement of a person or people away from their home or home region. The UNHCR defines 'forced displacement' as follows: displaced "as a result of persecution, conflict, g ...

of local peoples, with

indigenous groups Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...

often being highly vulnerable. This happens via the influx of non-indigenous settlers who migrate into the region for employment or to exploit local resources. Non-indigenous settlers can attain or claim the land title through land grabbing, land speculation, and illegal colonization.Koji, T., Hoban, C., 1997 Roads and the environment: a handbook, p. 252. The World Bank, Washington, DC. While migration increases urbanization, potentially leading to increased development, this is at the expense of indigenous populations. Road expansion is particularly threatening for vulnerable remote communities. Large road projects generate an influx of temporary migrant workers, which increases the demand for services such as prostitution and black-market products.Carswell, J.W., 1987. HIV infection in healthy persons in Uganda. AIDS 1, 223–227. Beyond this, road expansion in remote areas also promotes activities such as illegal logging,

illegal mining Illegal mining is mining activity that is undertaken without state permission, in particular in absence of land rights, mining licenses, and exploration or mineral transportation permits. Illegal mining can be a subsistence activity, as is the cas ...

, poaching, smuggling and illicit drug production. Such activities can have chain-reaction-like impacts on the traditional culture and social structure of local communities. The scale and pace of these impacts are most severe in indigenous communities. The traditional culture and lifestyles of indigenous groups that have lived in remote areas for many generations are substantially altered by new roads. Unprecedented road penetration into their natural landscapes can damage the aesthetic of the landscape and traditional cultural practices, the influx of non-indigenous land settlers violates traditional land rights, and increased commercial poaching alters traditional hunting practices. All such consequences degrade the cultural heritage of indigenous communities, increasing loss of their traditional identity and culture.

Diseases

Temporary workers for road building and the influx of settlers resulting from road building bring new pests and diseases into communities. This mechanism is particularly dangerous for indigenous communities that have limited tolerance and immunity to new

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s. For instance, the construction of the Route 8 in

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

in the 1970s resulted in the death of 45% of one indigenous community within a single year. Road expansion increases the incursion of common diseases into communities such as

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

and also increase the vulnerability of communities to previously uncommon diseases such as HIV. This occurs as pests and pathogens use roads as a pathway to spread from one place to another place. Human enteric pathogen levels, for instance, were 2–8-times higher in Ecuadorian villages near roads than in more remote areas and incursions of

dengue fever Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin three to fourteen days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characterist ...

, malaria, and HIV were higher among people living near roads than in remote communities.

Conflict

The influx of non-indigenous migrants through road building, and the associated intensification of contact, create inter-group conflicts, such as seen between indigenous

Amazonian tribes Indigenous peoples in Brazil ( pt, povos indígenas no Brasil) or Indigenous Brazilians ( pt, indígenas brasileiros, links=no) once comprised an estimated 2000 ethnic group, tribes and nations inhabiting what is now the country of Brazil, befor ...

and

loggers Lumberjacks are mostly North American workers in the logging industry who perform the initial harvesting and transport of trees for ultimate processing into forest products. The term usually refers to loggers in the era (before 1945 in the Unite ...

gold miner Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface ...

s. Additionally, increased road access increases the spread of conflicting forces in war-torn regions, and the pace at which conflicts escalate. In the

Democratic Republic of Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

, more accessible regions were exposed to more violent events than less accessible regions resulting in a decrease of population welfare.

Reducing the impacts of road expansion

There are a few ways of reducing its impacts.

Expanding existing roads

Following the 'first-cut-is-the-deepest' dictum, the expansion or upgrading of roads in previously settled areas is believed to cause less environmental impact per kilometer of road development than where new roads penetrate intact forest landscapes. Beyond this rule of thumb, however, road expansion threatens remnant habitats of

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

and leads to the loss of remnant areas of rare

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s (e.g., lowland tropical forest). This is increasingly common as new major road developments seek to consolidate earlier, rudimentary road networks (often characterized by penetration roads, improvised roads, and rough tracks) to expand agricultural and industrial activities in partially deforested landscapes. Many economic appraisals of road projects in developing countries have found that improving existing road infrastructure is more beneficial than construction of new road infrastructure. Examples of such consolidative road-expansion projects include the various 'development corridors' of Africa, meant to facilitate trans-national economic activities;

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

's development corridors as per its Master Development Plan, meant to accelerate agro-industrial development, mining and timber extraction; and China's Belt and Road initiative. In northern

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

, Indonesia, proposed road developments extending the

Trans-Sumatran Highway The Trans-Sumatra Highway (Indonesian: ''Jalan Raya Trans-Sumatra'') is a primary north–south road in the Indonesian island of Sumatra, 2,508.5 km in length, and connecting the northern island at Banda Aceh to Bandar Lampung in the south ...

if they were to occur will affect six of the eight local conservation priority areas of the Leuser Ecosystem, comprising 89% of the remaining

Sumatran orangutan The Sumatran orangutan (''Pongo abelii'') is one of the three species of orangutans. Critically Endangered, and found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recent ...

's habitat. In fact, Forest conversion due to road development in this region has been projected as a major factor influencing the decline in

orangutan Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genus ...

populations.

Limiting road expansion

Road planning to limit the extension of existing roads in ecologically vulnerable areas or mitigation measures such as restriction of road width and the inclusion of faunal overpasses is an emerging field of conservation science. Aside from the environmental benefits, limiting road expansion is beneficial for social and economic factors in developing regions. Many roads in remote areas have uncertain socio-economic benefits and surprisingly high economic, social, and environmental risks, and a cost-benefit analysis of 33 planned 'development corridors' in

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

concluded that less than one-fifth of the projects were clearly justified. Many road developments will be characterized by upgrades to rudimentary road networks, rather than entirely new roads. The Trans-Borneo Highway in

Sabah Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah borders the Malaysian state of Sarawak to the southwest and the North Kalimantan province of Indone ...

, Malaysia is one example, as virtually all road developments on this route planned for 2033 will coincide with existing logging roads or two-lane access roadways.Ministry of Local Government and Housing (2016). Sabah Structure Plan 2033, (Kota Kinabalu, Sabah, Malasyia: Town and Region Planning Department of Malaysian Ministry of Local Government and Housing).

Project assessment

The use of more rigorous approaches to project assessment and planning, such as cost-benefit analyses, proactive

land-use planning Land use planning is the process of regulating the use of land by a central authority. Usually, this is done to promote more desirable social and environmental outcomes as well as a more efficient use of resources. More specifically, the goals ...

, and strategic environmental-impact assessments are processes important for the improvement of road developments.

External links

James Cook University James Cook University (JCU) is a public university in North Queensland, Australia. The second oldest university in Queensland, JCU is a teaching and research institution. The university's main campuses are located in the tropical cities of Cairn ...

– Centre for Tropical Environmental and Sustainability Science
Reducing the global impacts of rapid infrastructure expansion

Global Road Maps
A strategic approach for advancing nature and sustainability.
Laurance Lab

laboratory website with information about the team and current projects.
Road Free
A key website for those concerned about road impacts on wilderness and biodiversity
Alert Conservation:
A scientific organization that focuses on tropical forests, wilderness, and environmental conservation issues. Provides links to many topical articles, conservation news, and research.
Conservation Bytes:
A lively website for news and opinion about nature conservation.

References

{{Reflist Roads Environmentalism Transportation planning