System Maintenance

Factors that lead to the adoption of an automated maintenance system include:

• the need to minimise system downtime especially when this would affect public confidence in the traffic management and information services that are delivered
• the size and evolving nature of the equipment inventory due to technological advances, which often results in mixed equipment types
• the greater the number of stakeholders involved (for example, manufacturers, vendors and suppliers, maintenance staff, sometimes from different agencies)
• integration issues associated with many different device types and brands
• difference between ITS maintenance (which mostly involves electronics and communications) and roadway maintenance
• need for consistent procedures and practices
• need for accurate and complete ITS inventory (devices, equipment and materials, such as fibre-optic cables)
• need for an efficient work-order-based maintenance system
• ability to track expenses (such as, labour, materials, parts, entire devices) to the specific device or subsystem
• need for timely, accurate and comprehensive reporting
• limited funding – the need to be efficient and effective with available resources, while at the same time justifying the maintenance programme

Most Traffic Control Centres (TCCs) have “up-time” targets for system availability that challenge the maintenance team to keep devices operational at least a certain percentage of time, for example, 98% or 99% availability. Only automated systems can both organise the maintenance activities and keep track of them. An ITS maintenance management system and a communications management system are part of the ITS operation, just like the TCC software. If the RNO organisation operates its own comprehensive telecommunications networks, this will justify a telecommunications “network manager”, which is common place in the telecommunications sector.

Systems maintenance can be performed either by in-house staff or outsourced to others—usually original equipment suppliers but also third party maintenance companies. In some regions the trend is towards outsourcing systems maintenance to private contractors. The substantial differences in the nature of ITS and roadway maintenance, generally leads to ITS maintenance being outsourced to a specialised electrical contractor.

Some large consulting firms are increasingly expanding their involvement in this business, sometimes called asset management.

The purpose here is to maintain ITS equipment or restore it to a condition that can effectively handle the assigned functions, at the lowest possible cost. To achieve this objective, the operator must:

• reduce the probability of equipment failure, quickly detect problems and take prompt and effective action
• upgrade equipment and systems (including software upgrades) to adapt to changing conditions

Organisational arrangements will depend on the size of the maintenance operation, the volume, nature and location of equipment, and the resources and skills available. Organisations will need to determine the scope of maintenance activities to be undertaken internally by the operating organisation and those that will be sub-contracted.

Effective maintenance is based primarily on detailed wording of supply contracts, follow-up and effective handover. This is to ensure a precise definition of the work to be performed, conditions of delivery, contract deadlines for restoring service and penalties for non-compliance. It also relies on:

• extensive documentation of equipment maintenance procedures
• fault diagnosis equipment for dynamic equipment and to remotely restart systems
• prioritisation of safety-related maintenance (such as road tunnel ventilation equipment, lane assignment signals)
• qualified (training, accreditation) and available staff (noting any restrictions and aiming for permanent assignments)
• complete maintenance contracts and follow-up
• spare parts inventory

Motorway Maintenance Management Systems (MMMS) generally operate on limited-access roadways, which carry high volumes of traffic at relatively high speeds. Disruption to traffic adversely impacts traffic operations. Fortunately, many ITS devices are located off the roadway, but within the rights of way, so maintenance activities can be conducted without directly interfering with traffic. Even in these cases temporary traffic control devices may be required for the protection of the maintenance crew. Efficiency of maintenance operations is essential.

The mere presence of maintenance vehicles causes driver distraction (“rubbernecking”), in the same way as roadside incidents. This is a particular concern in restricted situations, for example part of a tunnel or long bridge. Working on, or adjacent to, live carriageways is hazardous and some simple precautions are needed – for example, high visibility clothing, hazard lights and deployment of temporary traffic management to close lanes.

There is greater traffic disruption when the maintenance crew must work over an active lane or median shoulder, such as on the exterior of a VMS. When this happens, the crew is generally required to close the lane(s) over which they work and deploy temporary measures to maintain traffic flow. This work should, whenever possible, be done during off peak times to minimise the adverse effect on traffic. The work is often contracted out to specialist firms to provide temporary traffic management. The TCC will need to be vigilant in ensuring that measures to maintain traffic flow are in place and are operating effectively at all times.

These considerations apply equally to maintenance of routine traffic control and information devices, such as fixed signage – so general maintenance should follow the same practices as the ITS maintenance agency. The TCC should be notified whenever there are activities on the motorway, particularly if lanes are to be closed. Some countries use Lane Closure Management Systems to schedule and manage closure requests and contractor roadwork.

Particularly dangerous work sites – for example on one of the traffic lanes – should be protected by a crash barrier (crash-attenuator or crash cushion) such as a vehicle or trailer positioned upstream of the lane closure. In Santiago, Chile, one of the urban toll road operators requires all providers of maintenance to equip work crews with such equipment.

The primary difference between motorway and urban arterial road networks is that in the urban situation considerably more maintenance has to be done on, or immediately above, the roadway itself. Traffic signal heads, supporting span arms, signs, wires and overhead vehicle detectors are all located over the roadway. Devices off the roadway, such as signal cabinets and other ITS equipment, will also generally be located in less open spaces. If a hard shoulder is not available it is likely they must be accessed from a traffic lane. Lane closures are far more likely on urban arterials roads and city streets.

Many high-capacity urban arterial roads experience traffic speeds that are not significantly slower than a motorway. Other roads have lower traffic volumes, particularly off peak, and traffic speeds may be lower too. Temporary traffic management is important and without it, conditions may be unsafe. The number of movements possible (such as driveways and turning movements) also greatly increase hazards. The paramount objective must be the safety of the maintenance crew.