This section suggests how the indicators described above in Chapter 3 might be presented. It will have to be remembered that presentation of individual indicators constitutes only a part of presentation of the whole picture, and will have to be supplemented by a summary consistent with the whole evaluation framework, presentation of the principles underlying the models, main findings and conclusions etc. This overall picture must be tailored to the preferences of the audience (what do they need to make up their minds?) and the background knowledge they have. Our evaluation framework provides the flexibility needed for that.
4.3.1 Economic efficiency
Economic impacts of a transport scheme are often crystallised into one figure, like the cost-benefit-ratio. In order to do this, several components have to be monetised and evaluated. This background information should be shown in a transparent way for credibility to all stakeholders.
Suitable methods are tables, probably backed up with bar charts. For each strategy presented, we propose to present the results in a table with columns for each category of affected sectors (households, firms, government and external) as shown in Tables 3.1 and 3.2. The columns might be further divided into sub-sectors if the data allows and if it is found necessary. For instance, firms may be divided into transport operators, property developers etc. The rows will indicate the type of impact, such as travel time benefits, monetary benefits etc. For analyses where more than one year is modelled, rows might also show the benefits by year. One of the purposes of such tables is to show broadly who wins and who loses by the strategy.
Elements of economic efficiency, notably the user benefits, may also be presented by zone in a map. This is in effect one of our equity indicators.
It has to be remembered that several issues covered in the economic calculus are also part of other impact descriptions (accessibility, accident costs, environmental costs, even land-use impacts). Implicit double counting through presenting the same impacts in different ways is a real risk here, maybe not so much with planners, but with decision makers and the public. Therefore, it needs to be pointed out very clearly how the data presented comes together in the overall evaluation of sustainability.
4.3.2 Protection of the environment
All environmental impacts cannot be presented in the same way, as their spatial properties differ significantly. Some are local (like noise and particulates), some regional (like NOX) and some global (like CO2). Also, their temporal frames are different, immediate like noise, or cumulative like Pb.
In addition to presenting the levels of emissions or noise, or the positive or negative changes, there is the need to quantify the number of people exposed to the improved
or worsened air quality or noise at different locations.
Unless the environmental impacts are added together by way of monetary unit values, the group “environmental impacts” means many tables, bar charts and maps, which may bias the relative weights of individual items inside the group, as well as between environmental and other impacts. To keep things simple, we will often want to opt for monetisation of the impacts.
For some of the local effects, like local pollutants and noise, presentation by zone or for instance road class might be possible, but for the others aggregated figures of the levels of the effects are sufficient.
Indicators related to the protection of valuable areas, urban sprawl and fragmentation are perfectly suitable for thematic maps and much less suited for monetary evaluation.
From the above, it is clear that several types of presentation are needed to cover the various environmental aspects, and careful consideration must be used in selecting representative items for different presentation purposes. The intention is not to flood decision-makers or public with detail, but to show the importance and relevance of the impacts.
4.3.3 Liveable streets and neighbourhoods
Indicators of liveable streets and neighbourhoods may be a subgroup of the accident indicator, namely accidents involving pedestrians and cyclists. Consequently the same presentation methods as for the accident indicators (see 4.3.4) apply here. If data allows, the spatial distribution of accidents involving pedestrians and cyclists should be used to show where in the city the improvements occur.
An indicator related to social, cultural and recreational activities or the quality of neighbourhoods may also be used if the destination choice has been affected by the quality of the zone. For these indicators thematic maps visualise the differences between the zones best, perhaps even with subdivision according to activity. In modelling, some suitable intrazonal accessibility indicators might be used and also utilised for presentation purposes.
4.3.4 Accidents
For the visual presentation of accidents our first thought is a detailed map with accident data on it. However, regarding evaluation of future plans there are no empirical data on accidents to present. Even so, there might be some spatial indicators of estimated accident rates or costs.
Regarding accidents, both the absolute levels and relative changes are usually of importance for the authorities involved as well as for the decision makers and the public. In many countries fatal accidents are of special interest. Therefore, representing the predicted development of these accidents by severity levels on zone level, by road type or even aggregated over the whole area may be an advantage.
Possible presentation methods for accident indicators are maps, tables and charts on zone level, by road class and zone or aggregated zones, and by severity level. An example of basic presentation would be a thematic map of relative changes of accidents by zone with absolute numbers of accident as a bar chart on each zone.
Since unit costs of accidents of different degrees of severity are accepted in many countries and allow for aggregation of accident of different degrees of severity, presenting accident costs is clearly an alternative to presenting accidents by number.
4.3.5 Equity and social inclusion
Equity and social inclusion indicators address accessibility for different groups such as those without a car or the mobility impaired, losses and gains by socio-economic groups and by residential locations, and the issue of how much of the benefits are kept inside the urban area.
Appropriate presentation methods vary from thematic maps at zone level to charts and tables both at zone level and for the whole area. Information on relative values in comparison with the average in the city, or on relative changes from the base scenario, are at least as important as the absolute figures.
For various reasons, presentation of results with respect to equity is perhaps the most difficult of all. Distributional impacts have many aspects, and focusing on one of them may mean to neglect other, equally important aspects. Moreover, the aspects that appear to be the most important before the study started may not turn out to be all that important in the end. There is a danger of neglecting inequality that affects less vocal groups and concentrate on issues that are high on the political agenda at the time. On the other hand, there is obviously a need to concentrate on one or a few indicators.
There is little actual experience with presenting inequality indicators in a systematic way. We even have too little experience with computing them, choosing parameters and understanding the normative content of such choices.
The visual impression of inequality that can be had from a map will be very dependent on the chosen level of aggregation, scale and colouring – see Chapter 17. Consciously or unconsciously, issues can be downplayed or exaggerated by the technical choices we make in presentation. This, by the way, is not only true for maps but also for charts and tables.
For all of these reasons, presentation of equity results must be very carefully planned.
4.3.6 Economic growth
The economic growth indicator proposed in Chapter 3 is a global indicator derived from user benefits, producer surpluses and government surpluses. Thus similar methods of presentation to those for the economic efficiency indicator can be adopted.
The economic growth indicator might also be used as a regional indicator reflecting differences with respect to growth potential within the city area. Only user benefits admit of such zonal representation. However, it is not even probable that the user benefits within transport and land use will be retained within the origin zones. If anything, it would be better for this purpose to aggregate user benefits by destination zone, since they will probably translate into lower wages for the firms at the work trip destination zones, profit for shops and higher rents for property owners.
4.3.7 Summary principles
Two main principles for the presentation of PROSPECTS indicators can be drawn:
• The level of all major indicators in all tested strategies should be presented in a table. The tables guarantee the transparency of the evaluation. The tables then can provide the data for comparison of selected strategies through bar charts, pies or other chart types suitable for that particular indicator.
• Visualisation using thematic or ordinary maps and GIS should be used wherever possible. This assists a layman (decision maker and public) to quickly grasp the main points of the presentation.