It is widely accepted that high population densities are essential for sustaining cost-effective public transport. Put simply, high infrastructure costs need to be shared between a large number of users to make individual trips affordable.
Urban sprawl generally makes today’s public transport solutions ineffective and expensive. This is evident when looking at the geography of neighbourhoods and districts within many cities. The probability of having public transport located nearby is strongly correlated to the urban population density of a neighbourhood or district.
Attempting to stop and reverse urban sprawl is therefore one of the most important measures to provide better access to public transport, given today’s typical solutions for public transport.
FROM RAIL-BASED PUBLIC TRANSPORT TO CAR DEPENDENCY – AND BACK AGAIN
Prior to industrialisation, cities were still small and compact. As a result, rail-based public transport developed during this era was built for short distances and without competition from the private car. Labour was cheap and the cost of running these services was considerably lower than it is today. This created a public transport system characterised by short distances between stops and low travel speeds.
The private car started to become the preferred form of transportation in the middle of the 20th century. This facilitated the growth of cities beyond the current network of public transport. At the same time, private transportation became preferable to public transport, which created a self-generating cycle of urban sprawl and car dependence.
In order to compete in terms of travel time, public transport needed to increase its travel speed. To adapt to the changing structures of cities and to passenger demands, public transport was developed to facilitate longer travel distances in urban areas. This also led to longer distances between stops, shorter travel times, and reduced operating costs.
The result of this development in transportation modes and city structure is a mix of
fast, effective new routes and old time-consuming routes with low travel speeds. This is readily apparent in many European cities today. A short average distance between stops is
often due to the line having a long history, while shorter distances between stops is typical of new, more effective systems.
PROXIMITY TO PUBLIC TRANSPORT NETWORKS IS A FUNDAMENTAL FACTOR
If the walking distance to the nearest stop takes as long or longer as the entire trip (by bus, for example), this can be perceived as an obstacle. It may also result in the user choosing another means of transportation. In general, users tolerate walking longer distances when the entire trip takes longer than the time it takes to walk to the nearest stop.
Acceptable walking distances and journey times also depend on who you are. In general, the distance an adult is prepared to walk – assuming the alternative is to use the car – is 500 metres. But the walking speed of healthy adults is not the only factor. While an adult typically takes six minutes to walk 500 metres, the elderly and children typically take 11 minutes to walk the same distance.
Two aspects that should be taken into consideration before designing a public transport network are therefore:
- Who will be the typical traveller?
- What is the extent of competition from other modes of travel?
The “passenger market” of a station or a stop is defined by the citizens living and travelling in its surrounding area. Station location has a major impact on walking distances, and therefore also on the passenger market surrounding the stations. This is particularly true for stations outside city centres. In such cases, however, it is often possible to reduce barriers around stations to increase the surrounding passenger market, which may not be as easy in a city centre where demand for space is that much greater.
One common way to develop a traditional public transport system is to create a network of main corridors and service routes. Main corridors are typically served by modern trams or high capacity buses, while smaller buses typically run on service routes. Effective main corridors comprise several routes and offer high-frequency departures. Service routes supplement main corridors, covering a larger, less dense area and having less frequent departures.
This type of interdependent system therefore offers a high degree of accessibility for several different groups of users, while still providing options for reasonable travel times to destinations relatively far away.
In the absence of service routes, however, the network would be less accessible. This is especially true for people who have difficulty walking or cycling to the station (and where car parking options are limited).
MANAGING ACCESS TO PUBLIC TRANSPORT FOR PEOPLE WITH DISABILITIES