Transportation also leads to noise pollution, water pollution, and affects ecosystems through multiple direct and indirect interactions. With the continuous growth in transportation, increasingly shifting to high-speed transportation modes, these externalities are expected to grow.

While transportation is essential for global trade and mobility, it carries significant negative externalities, primarily environmental and social. Environmentally, the transportation sector is a leading contributor to climate change, accounting for roughly 20-25% of global CO2 emissions due to the combustion of fossil fuels in cars, planes, and ships. It also causes localized air pollution through the release of nitrogen oxides (NOx) and particulate matter, which are linked to respiratory diseases in urban populations. Socially, transportation infrastructure can lead to "habitat fragmentation," where highways and railways split natural ecosystems, threatening wildlife. Additionally, noise pollution from airports and busy roads is a major public health concern, linked to increased stress and sleep disturbances. In 2026, many cities are addressing "congestion" as a negative effect, where the time lost in traffic results in billions of dollars in lost economic productivity annually.