The organisations that operate and manage ITS systems and services can each decide to do some or all of their own maintenance or sub-contract it to other organisations. The increasing complexity of ITS implementations and the services that they provide tends to promote the idea of using sub-contractors.
Advances in the technologies found in the system components and communications networks used by ITS implementations have reduced their need for regular maintenance. The days of frequent periodic maintenance activities for hardware and equipment are fast going and are being replaced by a philosophy summed up by the expression, "if it isn't broken, don't fix it".
Modern day roadside equipment will normally only need occasional replacement of light sources and sensors. Even this is declining with light sources now operating at low voltages. In other respects the trend is for maintenance activities to only be needed following the effects of extreme weather conditions, such as extremes of temperature flooding and high winds. There are some exceptions to this trend, such as mechanical barriers at car parks or bridges, and equipment in tunnels that will need extra safety checks that will need to be carried out on a regular basis.
Control centre and communications equipment is following the trend towards little or no maintenance activities. When anything does go wrong the tendency is to replace rather than repair.
The one exception to the "if it isn't broken, don't fix it" mantra is software which is often updated periodically, either because problems have been found or to include improvements. This is particularly important for any components that will be connected to the Internet, as they must be protected by sophisticated firewalls and software to prevent unauthorised access. Whenever software changes are made Configuration Management (CM) needs to be employed to ensure that the changes are managed and that it is possible to revert to the unchanged version if problems arise.
Except for the large organisations that often manage ITS implementations in cities and across states, provinces or nations, it is usual to employ sub-contractors to carry out maintenance activities. These sub-contractors may be specialist maintenance organisations, or the component suppliers, particularly for roadside components.
Whatever form of sub-contractor is used, the scope and content of their activities must be defined in a contract, sometimes called a Service Level Agreement (SLA). The SLA must define such things as what is to be maintained, the hours and days during which the sub-contractor must attend to a reported fault, the response time for a reported fault, how long a repair can take, at what point must a replacement component be fitted, spare stock holdings, plus the competence and availability of the sub-contractor's staff. A cost structure must also be included, to either fix a price for each activity, or fix an overall price for all maintenance activities. SLA's usually only operate for a fixed period of time (2-5 years) and will need to be renewed when the time has expired, often through a tender submission process.
The possible exceptions to the use of sub-contractors for maintenance activities are large cities, or other geographic areas for which the scale of the ITS implementation is large, particularly in terms of the amount of hardware used. In these instances the amount of maintenance work required will make the recruitment and training of specialist hardware maintenance staff, providing a stock of spares and a repair facility, a benefit to the organisation operating and managing the ITS implementation. Sometimes the organisations in adjacent areas can combine their maintenance activities to benefit from not using sub-contractors.
Software maintenance is usually different because even in a large ITS implementation there is not the same quantity as there is for hardware, and understanding, modifying and replacing it is more complex. For example, the software for a typical urban traffic control system may have between 250,000 and 500,000 lines of code, which will take a software engineer several months to fully comprehend before any changes can be made. Therefore it is better to get the software supplier(s) to maintain what they have supplied.
It is likely that in most countries it will be maintenance of hardware and communications links that will need to be provided, as software maintenance is almost always best left to its suppliers.
One way for a developing country to proceed is for ITS maintenance to be done by the component suppliers and communications providers. Quite often a period of maintenance can be included as part of their supply contracts. All the provisos about such things as Service Level Agreement (SLA's) mentioned previously need to be included. Items such as maintenance equipment and spare parts should be stored locally. How the spare parts are provided is something that has to be negotiated as part of the maintenance contract(s). If the service providers take responsibility for ensuring that sufficient spare parts are available it can sometimes be a question of balancing a possible reduction in the cost of maintenance against the greater freedom to change contractors at the end of the maintenance period.
Other factors to be born in mind when negotiating maintenance contracts include what local presence the maintenance contractor(s) will have, and to what extent the contractor(s) will employ local people. The latter can be very important. For the long-term future of the ITS implementation it will be advantageous if the local employees acquire the training to give them the technical skills needed to carry out the maintenance activities.