Let's examines how in different ways that transportation decisions affect land use patterns and resulting economic, social and environmental impacts. These include direct impacts on land used for transportation facilities, and indirect impacts caused by changes to land use development patterns.
Inter-ralationship of Transportation and Landuse
In particular, certain transportation planning decisions tend to increase sprawl while others support smart growth. Land use patterns can have diverse economic, social and environmental impacts: some some require less imprervious surface per capita and so preserve more open space, and some are more accessible and so reduce transportation costs to businesses and consumers. Transportation planning decisions influence land use directly, by affecting the amount of land used for transport facilities, and indirectly, by affecting the location and design of development.
For example, expanding urban highways increases pavement area, and by increasing urban fringe vehicle access encourages more dispersed, automobile-oriented development, commonly called sprawl, while walking, cycling and public transit improvements encourage compact, infill development, commonly called smart growth. For example, infill development tends to increase impervioius surface coverage within existing urban areas, but by reducing lower-density urban fringe development are reducing per captia road and parking supply, it tends to reduces per capita and total regional impervious surface area. Sprawl refers to dispersed development in low-density, single-use,automobile-dependent development areas outside of any city or town; population growth in cities and towns outside existing cities is not necessarily sprawl if the development pattern reflects smart growth principles. Transportation planning decisions affect land use, both directly by determining which land is devoted to transport facilities such as roads, parking lots, and ports, and indirectly by affecting the relative accessibility and development costs in different locations.
In general, policies that reduce the generalized cost (financial costs, travel time, discomfort, risk) of automobile travel tend to increase total traffic and sprawl, while those that improve non-motorized and transit travel tend to support smart growth. Planning decisions often involve trade offs between mobility and accessibility.By increasing the amount of land required for a given amount of development, generous road and parking requirements favor urban fringe development, where land prices are lower. It can be difficult to determine the exact land use impacts of a particular transport planning decision, particularly indirect, long-term impacts. Impacts are affected by factors such as the relative demand for different types of development, the degree to which a particular transportation project will improve accessibility and reduce costs, and how a transportation policy or project integrates with other factors. Conversely, if there is significant unmet demand for transit-oriented development, improving transit service and implementing supportive land use policies will probably stimulate smart growth.
Structured parking reduces land requirements and underground parking can be considered to use no additional land. In addition, motor vehicle traffic tends to reduce development density indirectly by increasing the need for sidewalk and building setbacks to avoid traffic noise and dust, so larger boulevards, highways shoulders and front lawns can be considered, in part, a land use cost of motor vehicle transport. It suggests that 5-10% of suburban land, 20-30% of urban land, and 40-60% of commercial center land is devoted to roads and parking. As previously described, automobile-oriented transport planning tends to cause sprawl by increasing the amount of land required for development, by improving accessibility to urban-fringe locations, and by degrading urban environments.. Another transport engineering text states: It can be argued that sprawl is a land use issue rather than a transport issue, since it can be controlled by land use policies such as development restrictions and zoning codes.
Few governments can establish and enforce effective land use controls where undeveloped land is easily accessible to urban areas. This reduces transportation costs, including internal costs and external costs. Smart growth improves non-drivers overall accessibility and reduces the portion of lower-income household budgets devoted to transportation. Because transit services and pedestrian facilities experience economies of scale, smart growth tends to increase service quality and reduce unit costs. Sprawl reduces unit land costs and so reduces costs for larger-lot homes, while smart growth reduces land requirements per housing unit, reduces parking requirements, and expands housing types, but may require structured parking and increase other building costs. Sprawl reduces housing costs for households that demand larger-lot single-family homes and generous parking supply, but smart growth reduces housing costs for households with more flexible housing and parking preferences.
More compact development, including reductions in the amount of land required for transport facilities such as roads and parking, frees up land for other productive uses, including businesses, housing, farmlands, and recreation.
Of course, actual impacts depend on factors, including other land uses and the quality of land displaced. This indicates that transportation policies that encourage more compact development and reduce the amount of land required for roads and parking facilities can increase the productivity of farming or other land-intensive industries. The following land use factors can affect energy consumption and emissions: Although individually each of these factors has relatively modest travel impacts, residents of traditional communities that incorporate most or all of these factors tend to drive 20-40% less than otherwise comparable residents of automobile-dependent communities Transportation facilities and sprawl sometimes threaten unique cultural resources, such as historic buildings, sacred land areas, neighborhood parks, older neighborhoods and towns, and traditional building styles.
Shashikant Nishant Sharma