case study

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Road Pricing

Providing the Technical Services to underpin the UK Department for Transport's Road Pricing Demonstrations Project

Client: UK Department for Transport through Detica plc

Context

The UK DfT was working with industry to establish how road pricing by time, distance and place (TDP) might operate reliably, accurately and affordably, whilst safeguarding privacy. The Demonstrations Project aimed to facilitate this by improving understanding of the feasibility of TDP technology.

In order to successfully run the Demonstrations Project a technical solution, consisting of software applications and physical hardware, was required. This technical solution, referred to as the Technical Services, provided facilities for data management and analysis, and for the definition and distribution of charging scheme rules. It also provided the technical infrastructure that facilitated the secure transfer of data between the DfT and the Road User Service Providers (RUSPs).

What we did

Working within DfT's Demonstrations Project team, integrate staff were responsible for the design and implementation of the Technical Services. This role included:

  • The design, specification and implementation of the secure web service interface used by the RUSPs to submit and retrieve data.
  • The design and implementation of the database schemas used to define the scheme rules and to hold the data submitted over the web service interface.
  • Generation and publication of scheme rules, including geographic representation of roads and regional boundaries.
  • Provision of monitoring and reporting services to support learning activities.
  • Data analysis.

Web services

The Web Service followed the WS-I (Web Services Interoperability Organisation) Basic Profile 1.1. Transport security was provided through using HTTP over SSL (Secure Sockets), with access security provided through use of basic user credentials (username, password).

The Web service was implemented using Microsoft's Windows Communication Framework (WCF) and used LINQ to SQL to interface to MS SQL 2008, where data was stored for further analysis.

Database design

SQL Server 2008 was used to provide database services. The databases themselves were designed to provide a generic structure, supporting a very wide range of possible scheme definitions. This design was also significantly influenced by developments in European standards for electronic fee collection (CEN 17575), therefore providing a structure with potential applicability beyond the Demonstrations Project.

Other tables within the databases were used to store records submitted by RUSPs and support basic back office functionality, such as the generation of (pseudo) invoices and the capture of operational status information.

Scheme rules

The scheme definition was contained within a number of database tables. These tables split logically into the following groupings:

  • Geography: providing a global catalogue of geography objects that may be referenced in scheme definitions
  • Classes: covering definitions of user, vehicle and time classes etc.
  • Scheme Detail: providing the details of charge objects and charges for specific schemes
  • Schemes: containing the catalogue of all defined schemes
  • Priorities: providing conflict resolution for overlapping schemes and/or classes
  • Audit: to support audit related activities

Monitoring and Reporting

Reporting Services were used to provide easily accessible basic statistical and usage reports to other members of the team. These included general data volumes and system usage against SLAs, and checking for missing and duplicated data. A set of SQL scripts and stored procedures was developed to support more in depth data analysis.

Data Analysis

Many aspects of data delivery and quality were analysed. These included data latency throughout the system, sanity checks to identify anomalies, analysis of technical performance through assurance records, and analysis of the practicality of aspects of charging scheme design.

Bespoke map matching algorithms were designed and developed to support the analysis of verification data. This data was collected using a differential GPS system combined with an inertial navigation system. The outputs of the map matching algorithms were subsequently used to provide baseline results against which RUSP performance was measured. A number of novel methods of performance analysis and presentation were developed and successfully used to help understand performance characteristics.

Where appropriate, third party tools were used to aid data visualisation. For example, a web service that supports real time and historic replay of charge record coverage using Google Earth was developed. Google Earth was also used to provide visualisation of verification data, colour coded according to map matching results, superimposed on the ITN (Integrated Transport Network) data layer.

Outcome

As a result of this work integrate offers:

  • Expertise in the design, representation, publication and application of road pricing schemes
  • In depth knowledge of technology suitable for intercommunication between the various entities involved in the operation of a road pricing scheme
  • Understanding of the issues and technical problems associated with the use of digital mapping data in the definition and operation of road pricing schemes