## 6 Results
### Experiment Inputs  
While our methodology can be applied to any sets of open and public transport networks, our experiment results are based on the transport networks of the Solent region of the UK, which can be summarised as follows. The Solent transport network is composed of pedestrian, bike and road open networks, as well as bus, ferry and train public transport services. Ferries connect the Isle of Wight with the mainland and connect the adjacent peninsulas of the coast of the mainland. Trains connect the main suburbs, towns and cities on the same islands, while the bus network provides the same plus a more extensive range of connections between local conurbations. The pedestrian transport network is defined by 202,816 nodes and 523,580 edges. The road network is defined by 141,743 nodes and 313,373 edges. The e-scooter transport network is defined by 204,037 nodes and 524,917 edges; however, e-scooters are restricted by geofence constraints to the cities of Portsmouth and Southampton. The public transport network consists of bus, ferry and train routes, of which there is a total of 1272 unique routes and 5830 stops. GTFS data define the timetables of the public transport networks as well as the dates that different public transport trips are available. Regarding the modelling of connections between different transport networks, nodes are generated in each open transport network corresponding to each public transport stop along with edges connecting those nodes to the nodes of the nearest existing edges in those networks. For connections between open transport networks, connection nodes are similarly generated if the nearest edges in the other networks are within some specified small distance. These additional connection nodes and edges are included in the totals reported above.  
Table 1 shows the parameters associated with each transport mode, which were collected from various sources, including www.carbonindependent.org (accessed on 4 April 2024), and capture the main characteristics and relative differences between each transport mode. The CO\({}_{2}\) contribution for public transport is based on that of buses (822 g/km) and is divided by 20 as an attempt to make the CO\({}_{2}\) accounted for directly attributable to each individual commuter. Walking is assumed to consume 60 calories per kilometre. The taxi cost (GBP/metre) is based on 40p per fifth of a mile and a fixed cost of GBP 2.50 per trip. The e-scooter fixed and variable costs are representative of those of a current app-based e-scooter trial (Voi Portsmouth and Southampton). The vehicle maximum speeds have been extracted from the static open transport network graphs and are used for the goal-directed heuristic scores used in the A* shortest-path algorithm.  
A day ticket public transport cost model has been selected because of its real-life relevance and simplicity, and because it leads to a special exception when checking whether or not one partial solution dominates another. The issue is that a partial solution without public transport may need public transport for its completion. Therefore, we need to avoid eliminating a partial solution which already includes public transport on the basis of its cost exceeding that of a partial solution without public transport by less than the cost of a day ticket; we must instead retain both partial solutions. Another exception is that we must avoid comparing and eliminating partial solutions if they do not end at the exact same transfer point within the same transfer point cluster. Partial solutions ending with public transport legs may end at different stops within the same transfer point cluster.