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

Abstract

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.