2. What are distributional (equity) effects?

The distributional effects of a transport initiative consist of the differing impacts across people affected by the initiative. They can involve:

  • Accrual of an initiative’s costs, benefits and other economic impacts to specific population groups
  • Distribution of these costs, benefits and impacts among these groups.

The term equity is normally used to refer to the ethical desirability of distributional effects among groups of individuals (for example, those relating to choice, affordability, livelihood and quality of life).

For the purpose of the ATAP Guidelines, the terms distributional effects and equity effects are assumed to have the same meaning and are used interchangeably.

Transport initiatives create a range of effects or impacts. These include changes in accessibility, mobility, travel time and safety, or environmental changes. Each of these, as well as their combined effects, will have distributional (equity) impacts on different population groups.

The distributional effects of transport initiatives typically arise from three sources:

  • Transport benefits including accessibility and mobility, greater transport choice, reduced time travel or safety (reduced risk of crashes)
  • Transport costs including who pays for the services (through user fees, taxes, etc.) and how the costs paid compare to the benefits received
  • Externalities including air and noise pollution, vibration, loss of visual amenity and open space, community severance, related property price effects and quality of life issues.

The groups that benefit from an initiative are not necessarily those who incur the costs of the initiative.

The distribution of impacts can take various forms and can be measured in different ways. Impacts may also be compared using a range of distribution dimensions including, for example, geography, age or mobility limitation. An analysis of the distribution of transportation impacts may also compare overall benefits to overall costs and other effects by population group.

2.1 Types of equity

Different forms of equity are relevant to the assessment of transport initiatives. Some of the most important forms of equity for transport initiatives are:

Horizontal equity refers to the ‘principle of equal opportunity’ and impartial treatment of different users. One form of horizontal equity consists of making the user pay for a ‘good’. In the area of transport, this essentially involves an improvement in quality of service (speed, reliability, comfort) in exchange for an additional payment. Another form of horizontal equity relates to the ‘polluter pays’ principle, which means that the user pays for the ‘damage’ they cause to society, such as environmental damage, accidents, congestion delays, etc (Raux and Souche, 2004).

Vertical equity refers to the ‘principle of difference’ and considers social inequities in the distribution of benefits among different classes of income groups. This consists of assessing the outcomes of policies with reference to the well-being of the most disadvantaged, who should be given the most attention. When applied in the context of transport policy, it means that the travel conditions of socially disadvantaged groups or individuals should be considered (Raux and Souche, 2004).

Spatial or territorial equity refers to the ‘principle of liberty’ and provision of equal conditions for citizens living in all parts of the country. This principle is associated with the right to mobility and access to jobs, goods and services from any location (Raux and Souche, 2004).

Inter-generational equity refers to benefits from the range of planned interventions addressing the needs of all, and recognises that social impacts should not fall disproportionately on certain groups of the population, particularly children and women, the disabled and the socially excluded, certain generations or certain regions (Vanclay, 2003).