Linjebussens vekst og fall i den voksende byen: en studie av bybussenes geografiske kvalitet Stavanger – Sandnes 1920 – 2010

Abstract

Linear city bus services are facing increased challenges from city growth. Increased number of inhabitants on increasing acres of built-up areas, makes it demanding to maintain adequate bus services within reasonable catchment areas. Number of departures per hour give a partial description of the bus service quality. Number of departures give reference to the time aspect of bus service quality, but say nothing about the geographical aspect. What part of the entire line network is within reach of direct bus service when frequencies are limited? To address the geographical aspect of bus service quality, the term network ratio is introduced. The term Network Ratio (NR) signifies what part of the entire line network is within reach of direct bus service to or from a certain place in the network. Network Ratio is given as a mathematical term whereby direct bus lines are calculated as a percentage of the entire network. The character and development of Network Ratio in a specific city is illustrated through an analysis of the urban growth of line network and built-up areas in the twin cities of Stavanger and Sandnes. The analysis is covering the period 1920 – 2000 in intervals of 20 years from the first bus lines were established in the urban area. Year 2010 is also included due to major changes implemented right after the turn of the millennium. Development show there is a close relation between bus network and built-up areas. When areas are being built, bus lines follow. The initial fase 1920 – 40 with extensive development of bus lines combined with some areal growth, is followed by a fase of consolidation 1940 – 60. The latter period is characterized by moderate areal growth, extended lines reducing network ratios, and increasing frequencies on the best bus lines. Extensive areal growth in the following period 1960 – 80, implies increased number of bus lines. As a consequence network ratios as well as frequencies are falling in the entire network. In 1960 certain lines had developed as much as 6 departures per hour, while maximum bus line frequency in 1980 has diminished to 2. New bus service development is introduced in the following period between 1980 and 2000. Numerous bus companies are united, and a more comprehensive planning of bus services are applied. The number of bus lines is stabilized at about 40, the fall in network ratio is reduced, and certain lines develop 4 departures per hour. Parallell to the bus development, growth of built-up areas is slowing down due to increased urban renewal with higher densities within built-up areas. In the period 2000 – 2010 new efforts are given to the development of bus services. Development of Network Ratio takes a new direction: The length of network links with high NR is increasing, while links with very low NR are diminishing. Number of bus lines is decreasing, and by 2010 almost 50% of the bus lines are served with 4 departures or more. Passenger comfort is improved in buses as well as on bus stops, and low floor buses are introduced to ease accessibility. Bus service quality is further developed after 2010. Digital services are introduced including digital ticketing, bus service information and real-time information on internet. In addition real-time information is presented at high frequency bus stops through visual screen and auditory speaker. Inside the buses name of next stop is given on screen and through loudspeaker. Further development of the bus services, should include improved Network Ratios in the entire network, as well as increased frequencies on major bus corridors. The latter is a task not only for the bus service planners, but just as well for the city planners and politicians in collaboration with the developers implementing urban density and allocation of important destinations. A last, but not least, objective for bus service development will be to improve punctuality and total travel time. Today a considerable proportion of city bus services are delayed in car traffic congestions. This is occurring especially on main streets and during rush hours. A set of different solutions are needed to address this question: 1. Dedicated bus streets (including car access to limited addresses) 2. Bus lines through local streets in concentrated housing, office and shopping areas. 3. Dedicated bus lane on main streets where possible. 4. Car traffic regulations on main streets without space for extra bus lane. As an overall vision, we need to cultivate the word of Flemming Larsen: urban growth as pearls on a string, as shown in fig. 13 and fig. 14.