Walk Links

Journeys by public transport involve walking to or from the point of access to public transport and when interchanging between vehicles or modes of transport.

People walk at different speeds. In some systems the speed of walking can be selected. In others an average walk speed is assumed.

A walk is usually closely associated with a wait or interchange time to ensure that the passenger has sufficient time to arrive at bus stop or platform before the service is due to depart. When walking from a bus stop or station to a final destination a wait or interchange time is not required.

If walks can be mapped exactly onto the road and footpath network the user may be provided with a diagram of the route or detailed instructions. OSCAR road centre line data from Ordnance Survey is one source of this. Such data does not usually have all the footpaths on and may need to be enhanced by data from local authority highways departments or else the results will not be the shortest route available. Consideration needs to be given to changes in height along the route, especially if the route involved lifts or escallators where more time will be needed.

An alternative approach is to show the crow flies distance, possibly overlaid with a map and calculate an average time. The danger with this approach is that it may be impossible to walk between the two points, for example is there is a river or motorway in between, or even just fields. Some systems allow barriers to be identified that any walking route would have to go round. There are further complications if these vary by time of day, for example if a shopping centre closes at night or if a path is unlit and pedestrians may choose to use a different route at night.

Often a maximum walk distance to walk is chosen by the user or preset for the user. If this is set too low the journey planning system may may say that the journey is not possible or find convoluted journeys or journeys at inconvenient times when a walk would have been quicker. On the other hand if the maximum walk distance is set too high, not only would the walk be uncomfortably long for the user but there is increased likelihood that the route will cross a barrier and not be available to walk.

Differences in the maximum walk distance are currently the principal reason for different journey planners finding different journey solutions from the same public transport data.