Public transport and town planning from a retroactive point of view C. Wallstrom, S. Johansson et al The aim of this project is to estimate the effect of town planning on traffic volumes and modal split in a regional perspective. The studied region is the south west part of Scania with surroundings. In this area, the buildings planned during the past 25 years (from 1965) are relocated into a more public transport orientated structure. The traffic volumes are calculated with use of modern programs for sequential logit models and network assignment (Emme/2). The relocated situation is compared to the current situation regarding traffic volumes and modal split. A comparison is also made with increased auto costs and increased public transport. A cornerstone in the project has been to design a realistic public transport system alternative with a reasonable location of built-up areas, and built-up areas adapted to local manners, and with a reasonable road net and public transport network. The density of built-up areas, car ownership, parking fees and other parameters are also given realistic values. As an example, the density of population for a densely built-up housing area will not exceed the prevailing one in an existing area of the same kind. The public transport network has about the same standard regarding service frequency as the current network. Since the built-up areas in the alternative scenario are more adapted to public transport this leads to a decrease of the public transport production (vehiclekilometres). 1965 has been chosen as base-year. The startingpoint is the infrastructure and built-up areas existing at that time. During the 25-year period up to 1990 vast
548 Urban Transport and the Environment infrastructure investments have been made as well as large-scale new built-up areas. Almost half of the inhabitants in south-west Scania live in apartments built after 1965. The number of inhabitants in the area is slightly over 400.000. The total population increasement and the increasement of the number of apartments and houses since 1965 are given conditions. However, relocations are made between and within cities and villages. The employment distribution 1990 is mainly supposed to be divided between cities and villages in the same way as it actually was in 1990. Also here, however, relocations are made between and within cities and villages. The migration of the inhabitants between cities concerns 7 % of the population in south-west Scania. If the relocation within cities and villages is included, the share increases to about 14 %. The employed people have been relocated in a similar way. The development of the built-up areas in south-west Scania during the period 1965-1990 is characterized by a large growth without any overall planning. The more public transport orientated structure puts built-up areas and public transport network together in bands ("string of pearls"). Examples are Stockholm, Copenhagen and London. The alternative regional public transport network is based on a structure of towns with Malmo and Lund as centra (see picture). The body in the traffic system are local trains, all passing both Malmo and Lund. The local train system consists of three main lines. They are all operated with departures every half-hour. The towns and villages are located like a "string of pearls" along these lines. The line itineraries give all stations along the lines direct connections to both Malmo and Lund. There is also a large number of departures. The local public transport network in Malmo consists of five tram lines at 6-10 minutes intervals, radiating from the city center. All the lines pass at least one railway station so that all important parts of the city can be reached with at most one change of line. The regional as well as the local networks are supported by buslines having lower frequencies. To analyse the alternative public transport orientated scenario, a number of traffic forecasts have been made using logit models and network assignment programs (Emme/2). In the basic forecast the alternative scenario has been compared with the actual situation in 1990. The increased attractivity of trains compared with buses (the so called train dummy) has been simulated by increasing the number of train departures with 25 % in one of the forecasts.
Urban Transport and the Environment 549 Furthermore, higher population density or relocation of built-up areas closer to the public transport network has been simulated by increasing the speed of walking from 4 to 8 km/h. Furthermore, in one forecast, the waiting time has been maximized to 15 minutes (i.e. the waiting time at departure intervals higher than 30 min. becomes 15 min.). Finally, increased car costs and faster public transport have been studied. The results show that the number of vehicle-kilometres by car decreases with 3 % in the alternative scenario for 1990. However, the number of car trips is unchanged. Consequently, the mean travel length by car has decreased. The number of public transport trips decreases slightly, while the number of pedestrian and bicycle trips increases a lot more in absolute figures. The public transport's share of the total amount of travel is nearly unchanged (the share is about 7 %). This can be explained by the fact that distance between domiciles and places of work/service centras has decreased because people have been moved from small villages to towns/cities at the same time as the larger towns have become more dense. The number of vehicle-kilometres in the public transport network has decreased with about 20 %, which is a considerable decrease. Concerning the remaining factors studied (increased departure frequencies for trains, increased walking speed, maximized waiting time), the doubled walking speed caused the biggest effects. Car traffic decreased with 1.5 %, while the public transport trips increased with 20-27 %. The results show that a public transport orientated structure in a short term gives minor effects on the market shares for public transport and car traffic, concerning the number of trips. If the amount of vehicle-kilometres for cars is to be substantially decreased, it is necessary that actions are taken against car traffic, for instance heavily increased car travel costs. A number of studies, in local as well as in regional scale, have shown that increased public transport standard is not only enough to increase substantially the market share for public transport. The exception is certain transport corridors where an effective and frequent train service can offer a travel standard, considering travel time as well as comfort, competitive with car traffic. The results in this study support these observations. The computations are based on the logit models with their parameter values, describing instant changes in travel behaviour as a result of different actions. In a long term period, a public transport orientated structure of built-up areas can result in dynamic effets, not able to forecast using current logit models. These effects can be a change of attitudes towards travelling, changes in car ownership and changed patterns of popualation and employment areas. There
550 Urban Transport and the Environment is also reason to believe that the logit models sometimes underestimate changes in travel mode. For these reasons the results should be carefully considered. SOUTH-WEST SCANIA - BUILT-UP AREAS 1965 AND PROPOSALS FOR 1990 ^ Built-up area 1965. Not included in the proposal ^If^feijvUt^f^- ''*-"**''^ flb Built-up area 1965. Decreased development compared to 1990 10 Km ^., i i i i, i i i i \^/ Built-up area 1965. Unchanged development compared to 1990 ^^ Built-up area 1965. Increased development compared to 1990
Urban Transport and the Environment 551 SOUTH-WEST SCANIA - ACTUAL PUBLIC TRANSPORT NETWORK 1990 Bectdnge srand. s/ Regional train itinerary with station Regional bus itinerary Bus itinerary with limited number of departures 0 5 10km I I I I I I I I I I I
552 Urban Transport and the Environment SOUTH-WEST SCANIA - ALTERNATIVE PUBLIC TRANSPORT NETWORK 1990 Regional train itinerary with station Regional bus itinerary Bus itinerary with limited number of departures 0 5 10km I I I I I I I I I I I