Oligopoly is a market structure where a small number of large firms dominate the market, leading to limited competition and the ability to influence prices.

In perfect competition, firms are assumed to be price takers, meaning they have no control over the market price and must accept the price determined by market forces.

Product differentiation refers to the strategy of creating unique features or characteristics in a product to distinguish it from competing products.

Economies of scale occur when the average cost of production decreases as the quantity of output increases.

Externalities in transportation economics are the costs or benefits that arise from transportation activities but are not reflected in the market prices of transportation services.

Railways are generally considered the most energy-efficient mode of transportation due to their ability to move large quantities of goods and people with relatively low energy consumption.

Natural monopoly in transportation economics occurs when a single firm can provide a transportation service at a lower cost than multiple firms due to economies of scale or network effects.

Ships are commonly used for long-distance transportation of goods due to their ability to carry large quantities of cargo efficiently and cost-effectively.

Congestion pricing in transportation economics involves charging a fee for using congested roads or infrastructure during peak periods to reduce traffic congestion and improve traffic flow.

Trains are often considered the most environmentally friendly mode of transportation due to their lower emissions and energy consumption compared to other modes.

Modal split in transportation economics refers to the distribution of passenger or freight traffic among different transportation modes, such as cars, trains, buses, and airplanes.

Buses are commonly used for short-distance travel within urban areas due to their flexibility, accessibility, and ability to navigate congested roads.

Externalities in transportation economics can be addressed through a combination of government regulations, market mechanisms, and technological innovations.

Airplanes are generally considered the fastest mode of transportation due to their ability to travel long distances at high speeds.

Transportation planning involves developing strategies for efficient and sustainable transportation systems, constructing new transportation infrastructure, and managing traffic congestion.