Client

Highways Agency

Project Title

Operational Technology Support and Development of Network Tools

Background

Controlled Motorways is an automated variable speed limit system. It operates using the Motorway Incident Detection and Automatic Signalling (MIDAS) system. The controlled section is fully instrumented with loop detectors at nominal 500m intervals, which count real-time traffic data including vehicle count, speed and traffic density. Signal gantries (at nominal 1 km intervals) automatically display mandatory speed limits in response to traffic conditions to help smooth traffic flow and provide protection to stationary or slow-moving traffic. Messages are also displayed to inform drivers of the reasons for the speed limits. The aims of the scheme are to smooth traffic flow, improve lane utilisation, reduce the incidence of stop-start driving, improve safety and journey time reliability, and reduce the stress of driving. 

TRL has monitored the M25 Controlled Motorway section since 1995. Over the intervening period TRL has developed deep expert knowledge of the behaviour of the Controlled Motorway system and of the traffic flows it manages. This expertise includes knowledge, methods and a range of specialist tools to collate, present and interpret data.

With the focus on reducing congestion and improving journey time reliability, the Operational Technology Support and Development of Network Tools project was commissioned by the Highways Agency Traffic Technology South.

Objective

TRL in its role as operational technology support body is responsible for increasing the efficiency and performance of Controlled Motorway systems.

In order to achieve this, TRL has charge of monitoring all components of the system, providing solutions and making recommendations to all parties involved. These include:

• monitoring automated and manual signal and sign setting
• MIDAS health checks to identify faulty loop sites
• real-time notification to regional control centres covering the appropriateness of any signs or signal settings
• direct support to the regional maintenance contractors management consultant (RMC/MC) team to advise on faulty MIDAS equipment and provide specialist network operations management tools
• responding to technology-related HAIL enquiries
• study of compliance with the speed limits on the M25
• development of automated network tools to facilitate monitoring such complicated systems as Controlled Motorways.

Methodology

In order to facilitate monitoring such complicated systems, the team has developed sets of automated and semi-automated network tools. These include MIDAS-HC and the MIDAS Maintenance Management System (MMMS).

Outcome

MIDAS HC is a semi-automated specialist graphical tool with features designed to aid in the analysis and visualisation of motorway traffic data, with the intent of ascertaining how well the MIDAS loops are functioning. The software has been developed to meet the current challenges of locating and diagnosing MIDAS loop faults. It's aimed at traffic engineers, traffic officers, data supervisors and transport advisors working in the field of motorway traffic management, monitoring and maintenance. The number of faulty loops in the M25 Controlled Motorway section has decreased considerably since the start of this project, with the secondary benefit of significantly reducing the number of inappropriate signal settings caused by the loop faults.

To aid and simplify the reporting of faults found on MIDAS-equipped highways and tracking of the subsequent maintenance and repairs carried out, TRL has produced an intuitive, web-based database called the MMMS, with custom-designed log-ons for the Highways Agency, regional managing contractors and regional maintenance engineers. It's based on the full device list for MIDAS and signal/sign devices such as loops, out-stations and transponders from the site-data database. The MMMS holds detailed fault records and maintenance actions of the regional maintenance engineers and symptoms from the MIDAS health checks. This approach creates a comprehensive system-performance knowledge centre enabling all stakeholders to fully appreciate the operational status of the MIDAS system.

Technologies Involved

Data storage