Effective Redesign and Organisation of the Inner-city Street Network Through New Forms of Public Participation

Effective Redesign and Organisation of the Inner-city Street Network Through New Forms of Public Participation


P Endemann, Planning Authority for the Frankfurt/Rhein-Main Metropolitan Area; W Müller, City of Ettlingen, DE



The development of new urban areas has to be considered as a major challenge for the urban structure of a city. This is particularly true when looking at the consequences for urban transport systems and the effects for the entire street network.

The reorganisation and the design of the interior street network of new development requires thorough planning in order to reduce the impacts of increased transport demand, such as negative impacts of motorised traffic on road safety, noise and gaseous emissions. Furthermore, the functioning of the street network must be guaranteed and additional traffic through surrounding neighbourhoods must be avoided.

Roundabouts are a vital solution since they contribute to provide safer streets, reduce environmental impacts, decrease the amount of road maintenance, and improve urban quality. As all roads have equal status, roundabouts reduce the dominance of main arterials and limit the negative impacts of motorised traffic as the intention is to reduce speeds and realise more permeability without negative consequences for traffic fluidity and capacity.

Despite of such advantages, the introduction of new measures always bears some conflict potentials with the citizens since they fear additional traffic induced by the new development as well as by the changing street network. Therefore, public involvement is an important issue to deal with.

Goal of the Paper The paper presents the Ettlingen case of the conversion of former military barracks into a new urban development, describes the development concept and visualises how the concept deals with predicted higher traffic volumes and the restriction of traffic impacts on surrounding neighbourhoods especially when looking at consequences for vehicles kilometres travelled. Focus is laid on the cooperation with citizens, the communication platform to direct public opinions and the interaction with politics.

The concept stipulated a carefully designed new street network based on a system of roundabouts. It aimed at giving priority to sustainable modes of transport (increased accessibility), improving overall road safety, reducing the impact of motorised traffic on other modes of transport and on the surroundings. As the new development structure filled an important gap within the city, a direct access to the main street network was created either from the new development areas or from an existing neighbourhood area.

This was necessary in order to achieve a better distribution within the network and to avoid overcharging of existing intersections. Consequently, accompanying traffic calming measures in the existing residential areas were required. According to estimations made before, a better distribution should lead to a reduction in kilometres travelled and gasoline consumptions which should go hand in hand with travel time savings.

Outcome: The results showed a considerable improve of transport conditions. This is due to remarkable reductions in overall traffic volumes and particularly within the surrounding neighbourhoods. Moreover, the new distribution of traffic and the creation of a direct access to the main street network did not produce any through traffic as it was feared by the public. Moreover, the chosen strategy of voluntary public consultation contributed to reduce the number of objections and to save time instead.

It is important to emphasise how an intensive cooperation with the citizens at different levels can lead to a successful implementation since public acceptability is increasing and citizens get informed and encouraged to participate in the process from an early stage on in order to avoid misinterpretations due to lack of information. Thus, the process also visualised how flexible structures could contribute to achieve a high level of acceptance by the public.

The outcome also permits a first discussion on the reasons for continuously decreasing traffic volumes as a previous traffic study has indicated already. Besides local factors such as transport policy, overall traffic calming aspects like population aging and changing gasoline prices have to be taken into account. We remarked the importance to analyse the effects on vehicles kilometres travelled, gasoline consumption and travel time budget in a before-after study. The results revealed predictions were even more pessimistic than the observations made afterwards.

The study also shows how some preliminary conclusions can be drawn from everyday work for future policy implications in addition to the results of a more comprehensive O-D survey.

Structure of the paper 1. Introduction: The rise of a new suburb Implications for urban transport development Consequences for public involvement 2. Context of urban renewal in Ettlingen Local Transport (Development) Plan Traffic census 1998 Prediction on traffic development (incl. gasoline consumption, travel distances and time budget) Zoning Plan 3. Objectives and Measures since the Area Development Plan has been established Main Street Network (Organisation & Design) Neighbourhood accessibility 4. Structure of cooperation Steps of the process Involvement of citizen and initiatives 5. Results: Reduction of overall traffic volumes since 1998 Better distribution of traffic volumes Traffic calming in neighbourhoods Reduction of vehicles km travelled, travel time budget and gasoline consumption Better overall accessibility (pedestrian, cycling) 6. Conclusions The paper discusses the effects of the results of several traffic census and tries to give some explanations on the observation with respect to

* Effects of surrounding roads built between 1995 and 2002

* Traffic calming in the city

* Effects of promoting alternative modes

* Gasoline consumptions reduced

* New habits

* Process of population aging


Association for European Transport