Regional and sustainable traffic management in The Netherlands: methodology and applications

Traditional traffic management is in most cases used only on a local level. It lacks an integrated and network wide approach. The main reason for this is that different network types (e.g. motorways and urban roads) are operated and maintained by different road managers. In practice these road managers are only responsible for their own part of the network and normally they do not communicate or cooperate that much. To deal with this The Netherlands has adopted a different approach, described in the handbook Sustainable Traffic Management (STM). This handbook was introduced in the Netherlands in 2003. The handbook is part of the Dutch National Traffic Management Architecture (TMA), which is a structured description of the complex system of traffic and traffic management measures. It can be used to develop and implement a consistent and accepted (in terms of political objectives) set of traffic management measures and the necessary technical and information infrastructure. The TMA consists of five sub-architectures, each describing one aspect of traffic management. For defining and using a consistent set of traffic management measures the Traffic Control Architecture is used. For the integration of the hardware and software, an Application Architecture is defined. The Architecture of the Technical Infrastructure describes the general ICT services in traffic management systems. The Information Architecture should harmonise the exchange and use of information and finally the Organisation Architecture gives a picture of the organisation required to facilitate traffic management. Of these five sub-architectures, the Traffic Control Architecture (TCA) is the most developed one and plays a leading role in the design, implementation and operational use of traffic management. The TCA describes the process to get from policy objectives to operational traffic control. In this process cooperation with all stakeholders involved is a key issue. To structure the process to come to a, widely accepted, traffic control architecture the Handbook Sustainable Traffic Management was developed. The handbook describes a step-by-step method that enables policy makers to translate policy objectives into concrete measures. The STM method consists of clearly defined steps that can be summarised as: defining policy objectives, assess current situation, determine bottlenecks and create solutions. This nine-step process helps to develop a network vision based on policy objectives, shared by all participating stakeholders. In addition, STM will provide the stakeholders with a first indication of the measures required to achieve effective traffic management in line with the shared vision. In order to facilitate the STM process, the Regional Traffic Management Explorer (RTME) was developed. This sketch and calculation tool supports the steps needed for STM and makes it possible to determine the effects of proposed traffic management services and measures. These effects can then be compared to the formulated policy objectives or other sets of measures. The RTM follows the exact same steps as the STM method, but from a quantitative perspective and in a dynamic modelling environment. It provides tools to formulate policy objectives and a general traffic management strategy. The objectives are quantified in a so called frame of reference and a user can input reference values for different (flexible) criteria, such as average speed on links, or (parts of) routes, travel times between origins and destinations, etc. When the policy objectives are confronted with the actual situation, bottlenecks can arise for the different criteria. The objective in the remainder of the STM process will then be to eliminate as much of these bottlenecks as possible. The STM and RTM facilitate this in two steps. In the first step, called services, resolving the bottlenecks is thought of in general terms, such as reduce inflow, restrict speed and increase capacity. In the second step these services are translated into actual measures, such as ramp metering, tidal flow lanes, speed limits, etc. The effects of services and measures can be calculated using a dynamic equilibrium assignment. This paper will discuss the workings of the STM method and the RTM. It will present the results of the application of both STM and RTM in the Netherlands. This paper shows that Dynamic Traffic Management (DTM), complex in its nature and involving different stakeholders, can be implemented successfully using a well-structured method, supported by quantitative models.