Communications

Data and telecommunications are the backbone of ITS deployments – providing the basis for system integration and regional deployment. Communication technologies are becoming more sophisticated – with increased capability at lower cost. The trend is shifting away from fixed communications (phone lines, cables) to mobile (radios, Bluetooth, mobile phones, WiFi) and use of the Internet.

A well-defined communication architecture coupled with use of standards for data exchange and physical interfaces helps ensure a harmonised approach to ITS deployments at the road-side and control centres. The choice of communications for ITS deployments is constrained by the type and capacity of communications networks that are available. The basic considerations for comparing and choosing between those available will be:

• bandwidth
• cost
• coverage of the road network
• latency (communications speed and delay)
• one-way or two-way communications
• continuity and reliability
• cybersecurity
• vulnerability to natural and man-made disasters.

Deployments must comply with any regulations imposed by the communication regulatory bodies and service companies.

There are two important levels of data communications to consider:

• area-level: information and data communications between operational centres
• local-level: data, command and control communications between roadside ITS equipment and a control centre

Area-level data communications are governed by the agreed data dictionaries and data exchange protocols – for example, the data communication protocols that link the road operators’ control centre with control centres operated by the police and emergency services. Road operators can share data through data exchange mechanisms as DATEX or have a common data base/data warehouse where all authorities can take out their data needs and inputs. An example is the Dubai Data Warehouse (Big Data) project in the Middle East.

Local-level data communications require the road operator to adopt communications standards and protocols for the control systems that are used across the network using open standards so far as possible – for example, data communications for traffic signals and VMS that are carried by the roadway telecommunications infrastructure

The use of high-volume communication links is limited by the lack of fibre-optic coverage and the type of the public switched telephone network. In many cases, a mixture of wireless, copper-wire and fibre-optics are used to transport data flows between the physical components of ITS at the road-side, traffic control centres, and in vehicles.

Some countries may have invested strongly in 3G/4G cellular communications networks and smart devices with low cost telecommunications. This provides a strong base for the development of services when basic data collection and traffic monitoring systems are not yet in place – equipped vehicles can provide data on speed, weather, incidents and journey times, all of which have value for journey planning and network monitoring.

If possible, the ITS deployment programme should not be locked into any single form of communication technology or equipment supplier. This is an area where ITS standards are critical. The choice of standards for data and communications protocols is important as an effective way of ensuring flexibility and independence of equipment supply. Poor choice of standards leading to lock-in removes the opportunity for market testing of equipment supply and economies through competitive tendering.

Use of existing infrastructure for general-purpose telecommunications reduces the time and cost to introduce ITS – and accelerates the benefits delivered to ITS users. At a later stage – with increased deployments – the use of dedicated telecommunication infrastructure can have advantages in terms of increased performance, reliability and flexibility in developing business models. (See Telecommunications)