The nature of transport and derived demand

Transport involves moving goods (freight) and people (passengers) between locations. It is typically a derived demand, meaning it stems from the need for other goods or services rather than being wanted for its own sake.

Reasons for derived demand in transport:

• For individuals:
  • Travel to work or for daily tasks like shopping.
  • Journeys for leisure, holidays, or other activities.
• For businesses:
  • Combining factors of production, such as raw materials and labour.
  • Delivering products to customers or markets.

Income elasticity of demand for transport

Income elasticity of demand (YED) measures how demand for transport changes with variations in real income. Overall, transport has a positive YED, classifying it as a normal good where demand rises as incomes increase.

YED for different transport modes:

• Car and air travel - These generally have positive YED values, meaning demand increases with rising incomes.
• Bus travel - This has a negative YED, making it an inferior good; as incomes rise, demand decreases.

Price elasticity and cross elasticity of demand for transport

Price elasticity of demand (PED) indicates how sensitive transport demand is to price changes, while cross elasticity of demand (XED) shows the responsiveness to price changes in substitute modes.

Price elasticity of demand in transport

Demand for transport is somewhat price elastic, but this varies by purpose:

• Recreational or leisure travel tends to decrease if prices increase.
• Commuter or essential travel is less affected by price rises.

Cross elasticity of demand between transport modes

XED applies when modes are viable substitutes.

Factors influencing the price elasticity of car travel

The PED for car travel is quite low, meaning demand does not change much with price fluctuations due to its perceived value and limited alternatives.

Key factors affecting PED for car travel:

• Journey costs - Fuel or toll prices influence decisions, but elasticity remains low because drivers prioritise convenience and comfort.
• Income levels - As real incomes grow, car ownership and usage increase, boosting demand.
• Availability of substitutes - Alternatives like trains or buses might reduce car use if their prices drop, but they are often seen as poor substitutes, resulting in low XED.
• Complementary goods - Prices of related items, such as insurance or parking fees, impact overall demand for driving.

Supply constraints, congestion, and long-term effects

In the short run, road supply is fixed because building new infrastructure takes time, leading to challenges during peak periods.

Short-run supply issues and congestion

• Fixed supply creates excess demand at busy times, such as rush hours, resulting in traffic congestion.
• Congestion can be managed by imposing charges like tolls or congestion fees.
• Appropriately set prices reduce demand to match available supply, easing overcrowding.

Long-term impacts of transport prices

Over time, transport costs influence location decisions:

• High prices may encourage people to live closer to work or amenities, reducing commuter travel demand.
• Businesses might relocate factories or shops to minimise freight costs, affecting overall demand across transport modes.