Final answer:
Increasing the capacity and width of roadways tends to encourage urban sprawl as it makes outward expansion more feasible, while also presenting a complex relationship with greenhouse gas emissions and sustainability. Effective urban planning must seek a balance between infrastructure growth and environmental stewardship.
Step-by-step explanation:
The question at hand is concerned with the impact of increasing the width and capacity of roadways on urban development and environmental issues, such as sprawl and greenhouse gas emissions. Increasing the capacity of roadways can encourage sprawl because it facilitates transportation over greater distances, making it easier for cities to expand outwardly. This expansion often leads to development of residential and commercial areas on what was previously undeveloped land, contributing to urban sprawl. In relation to sustainability and greenhouse gas emissions, while improved roads can help reduce fuel use by minimizing congestion and therefore the time cars spend idling, they can also lead to an increase in the number of vehicles on the road. This, in turn, can result in higher overall emissions unless complemented with other measures such as emissions standards, promotion of public transport, and encouraging the use of alternative, low-emission fuel sources.
Furthermore, the expansion of urban areas into previously undeveloped land might lead to the conversion of natural habitats into urban settings, which can cause issues such as habitat destruction, introduction of invasive species, and changes in local climate patterns.