Case studies
Structuring Means and Ends Objectives
The stated objectives for the Gateway Programmes are as follows (BC Ministry of Transportation 2006):
• To address objectives;
• To improve mobility of goods and people in and through the region;
• To improve access to key economic gateways (ports, airports, etc.);
• To improve the road connections between municipalities;
• To improve quality of life by removing regional traffic from local streets;
• To reduce vehicle emissions by reducing congestion-related idling;
• To improve connections to transit, cycling, and pedestrian networks; and
• To reduce travel times (especially during peak periods).
In the absence of any integration or structuring, the relative priorities or weighting for these different objectives cannot be deduced. The first step in developing a good set of objectives is to distinguish fundamental or ends objectives from means objectives. Objective hierarchies and means/ends networks are valuable tools in SDM to distinguish between means and ends objectives and the linkages among them. The structuring process for the Gateway Programme's stated objectives is illustrated in Figure 3.
It is common to find different time scales embedded within a single set of structured objectives. The avoidance of specific target or threshold levels in performance criteria makes the achievement of fundamental objectives an incremental and dynamic process. However, the timescales over which different alternatives are expected to act makes it necessary to sequence the means objectives network over time. From Figure 3, for example, increasing 'inter-modal connections' might affect transportation choices only after immediate improvements in 'reliability of transit' are achieved through 'reducing congestion'. While transit reliability and the resulting 'reduced time costs of people movement' might be expected to be immediate consequences of the Gateway Programme, the increase in transport choices as perceived by the travelling public may only be learning response from personal experience as well as information provided about these reduced time costs. The structured objectives can be modified therefore to distinguish the initial from subsequent (and therefore contingent) objectives, as shown in Figure 4.
Sequencing the timescales embedded within structured objectives often helps reveal these essential intermediate learning stages. Sequencing objectives also helps develop the expected consequence pathways of alternatives. These pathways are primarily causal, but can also include influence diagrams so that key uncertainties and decisions are included.