Over the years traffic systems have evolved to become increasingly sophisticated, in response to the increase in the volume of traffic and as technological advances have resulted in the ability to implement enhanced capabilities. However, the advent of emerging technologies promises a step change in capabilities but poses issues on how these can be integrated effectively with existing ITS systems to provide the most benefit to users, as Alistair Gollop explains.
“New technologies, like vehicle automation… are making travel significantly safer and more convenient. Advances in data processing are enabling governments and private companies alike to improve transportation services and better target investments. Government is rewiring to become more supportive of these beneficial technologies, while ensuring that they are safe and secure. This is both an opportunity and a challenge. Technological changes are coming fast and with greater frequency.” – former U.S. Department of Transport Secretary Anthony Foxx.
There is widespread recognition that technology on our highways is developing apace, and although the benefits which are envisaged are significant, the challenges these pose are also substantial.
How our roads became wired
Earlier traffic signal installations operated in isolation, although it was quickly realised that synchronising the operation of adjacent sites provided superior levels of performance. To start with, this was achieved by using sets of traffic plans pre-programmed into each traffic signal controller. This provided a good level of service, but relied on the accuracy of the real-time clocks in each cabinet. However, to update the plans, it was still necessary for an engineer to physically attend the site, and the scope to adjust plans in response to unexpected traffic patterns was limited. It was therefore realised that by running the plans from a centralised Urban Traffic Control (UTC) location, it would overcome these deficiencies. To achieve this, each site had to have a communications link to the control room. These were usually implemented using leased lines, which provided a permanent telephone connection between the central control room and each equipped signal installation. Due to the technology available at the time, the data interface consisted of a limited number of bits which could each typically request a traffic stage to run or confirm back to the control room which stage was currently running. A system called SCOOT was introduced to provide a synchronised method of control which was also vehicle activated. This could use the communications infrastructure to also provide data to the control centre about the volume of traffic leaving each signal installation, allowing SCOOT to dynamically adjust traffic plans so that the operation of subsequent signal sites could be optimised for the traffic which would arrive at them imminently.
This type of topography, where a control centre is linked to the majority of the signal sites on the road network has therefore become common place around the UK. Over time, the range of equipment installed on the highway network increased, including Variable Message Signs (VMS), CCTV and parking guidance systems. With these deployments, came a need to improve the supporting communications infrastructure. Luckily, over recent years, the ability to install higher speed and larger bandwidth communications into roadside locations has become much easier. In addition, the uptake of newer technologies has in part been driven by the withdrawal of older communications technologies, such as leased lines in the UK. However, with the ubiquity of the newer types of communications (including IP and broadband, along with wireless technologies), there is usually a solution available which can be implemented appropriate to the required functionality.
Nodes of opportunities
Because of this, most cities these days have a comprehensive communications infrastructure spread across their highway network, connecting the plethora of equipment used to manage and monitor traffic. It is probable that these traffic installations will soon become data nodes for a variety of emerging highway-based technologies over the coming years, due to their connected status and distributed nature across the road network. Using the principles of the Internet of Things (IoT), the collection of data from the physical world is possible using simple sensors which are permanently connected, producing data streams in real-time, use Cloud based services to allow additional sensors to be easily added without coding and archive data for later analysis. This provides the ability to amass an insight to a huge range of parameters which would have been difficult or prohibitively expensive to collect even just a few years ago.
The hardware used for IoT sensors is often thought to be inferior to ‘proper’ equipment, and although there is a huge variety of less accurate devices which are inferior, there are now many companies producing well engineered, accurate, calibrated sensors which offer much better value than traditional systems. In part, this is because of their ease of deployment, and low operational overhead. Many of the technologies obviate the requirement for any ‘civils’ construction to be undertaken to install them.
The equipment is often characterised by being small, so that it can be mounted on to existing infrastructure, such as lighting columns, sign posts or traffic signal poles. In addition, they are normally low-powered, so can operate from an internal battery (these might be recharged by a small solar PV panel but are typically quoted to have a 5 year or greater life expectancy) or may be wired in to an electrical supply from the host infrastructure it is mounted on. Remote sensors also frequently use wireless communications, although again those mounted on infrastructure such as traffic signals, may make use of the existing communications facilities available.
In the US, the City of Chicago has been installing what it has called the ‘Array of Things’, consisting of diverse sensors mounted together in compact, pole-mounted housings, typically located at traffic signals. These use the existing communications infrastructure to distribute hyper-local information back to the city authorities and to interested citizens, with detailed information across a wide range of parameters, currently including traffic, weather, pollution, flooding, noise and lighting conditions.
Stakeholders come together
The data produced by these kinds of technologies can benefit the operation of a city in many ways. It may be used immediately to trigger a response if an event is registered or if a threshold has been passed. These may include re-routing traffic if a localised flood is detected or changing traffic plans if congestion is forming. In addition, the ability to use historic data to undertake trend analysis or review the effectiveness of interventions can provide a valuable tool for making informed decisions for infrastructure investment. However, a key issue is the fact that this infrastructure should not just be used by one agency, but can benefit the whole community. In this way, additional sensors could be added to the system, which might not obviously belong within a traffic system. An example of this could be level sensors installed in litter bins to optimise waste management collection rounds. In addition, the system should be capable of conveying information, not only from different city authorities, but also a diverse range of stakeholders, including private entities, who may wish to contribute and share in the benefits of this data exchange. The benefits of an Open Data model may include encouraging a more diverse range of stakeholders to share in the associated costs, which would have traditionally been an overhead to a couple of different local authority departments.
Another benefit of the lower cost overheads generally associated with IoT type sensors, is the ability to increase the density of sensors. By increasing the numbers of data nodes across an area, the improved granularity of the information generated provides capabilities for ‘hyper-local’ insights to be generated, and the effects of any minor inaccuracies in individual sensor readings will be balanced across the larger number of sensors being used.
Additionally, because of the reduced needs for supporting infrastructure, they allow units to be deployed ‘off-grid’ in areas which have not previously been instrumented because of the difficulty and expense of providing electrical supplies and communication links. This is of particular interest in rural areas where roads can be susceptible to disruption caused by a very wide ranging set of causes, and sensors such as climatic and incident detection would have been prohibitively expensive to install.
A large proportion of the Strategic Road Network (SRN) (predominantly motorways and trunk roads), has been equipped with a comprehensive Intelligent Transport Systems (ITS) infrastructure over the years. Typically, this includes facilities ranging from emergency roadside telephones, incident detection, Variable Message Signs (VMS) and CCTV through to advanced SMART motorway implementations. However, there are still routes, which usually because of their rural nature, have not been equipped. Emerging ‘expressway’ standards for trunk roads could take advantage of using IoT type implementations for the technology requirements on highways to reduce the need for elements of traditional ‘heavy’ ITS infrastructure which can be difficult to deploy in more remote locations.
Protecting the asset
However, with the increasing reliance that will be placed on this infrastructure, the importance of protecting the integrity of its operation is heightened due to the levels of disruption which could occur if it is lost or corrupted. The security issues relate to both the physical assets and the implications of ‘hacking’ the data. The main security issues which equipment in the field faces is vandalism and theft. Apart from vandalism born from idleness, equipment can suffer from concerted attacks from individuals if they mistakenly think that the equipment is part of an enforcement facility. Theft of cables from duct systems has been well documented over the years, due to the value associated with scrap copper, however many items which are expensive to replace but have little ‘black market’ value have been stolen. To tackle this, the use of features such as internally locking chamber lids and mounting equipment so that it is high up or hidden within something like a traffic signal head, can make it much more difficult to steal assets.
The data being transmitted across the communications network is more susceptible to security breaches with the increasing diversity of equipment connected to the system. However, the likelihood of attacks affecting the network can be mitigated against by implementing normal IT security provisions. In addition, in the event of a successful attack occurring, the severity of the consequences can be minimised by an additional layer of defence. The capability to make dangerous alterations to equipment such as traffic signal controllers, is obviated by the in-built safeguards this type of equipment has. Unlike in the ‘Italian Job’, it is not possible to alter a range of safety critical settings remotely, so that it is not, for example, possible to turn signals to red or green unexpectedly. This should be a principle which is used across ITS infrastructure wherever safety features exist, to minimise the disruption caused by hacks or accidental setting changes.
There is currently an apparent ubiquity of data, with the availability of apps such as Google maps providing users with very detailed levels of information about the state of the highway network. However, most of these types of facilities do not integrate with traffic systems and operate in isolation. Many developers of IoT technologies have come from outside of the existing ITS industry, and use bespoke software or online tools to allow users to make use of the data which their products produce. Also, with the emergence of ‘big data’ it has become commonplace to use analytics tools to extract a meaningful insight to what is occurring. These include Carto – which provides insights that underlie location based data, Mapbox – which allows visualisations of data on cartographic bases, and Streetlight – that examines real-world travel patterns. Although these types of tools can provide valuable insights to the way in which our communities function and help in identifying causal factors for problems, they do not have a direct method of influencing the operation of the city to overcome issues or to optimise the operation of the transport infrastructure. So how can the disparate data sources be brought together to influence and inform the ITS systems which operate our transport networks and offer a pathway for additional stakeholders to gain value from their use?
The Urban Traffic Management and Control (UTMC) initiative was launched in the UK in 1997 by the Department for Transport. It sought to use modular systems based on open standards to allow highway authorities to achieve their transport objectives without being constrained by ‘single source’ solutions. Commercial UTMC products, such as Osprey from Mott MacDonald, use intelligent smart mobility applications to leverage the advantages of open standards, allowing equipment and sub-systems from different suppliers to work effectively together. Osprey uses three key modules to deliver an effective ITS system; Control – which is the core UTMC common database, Inform – that provides a suite of functionality to deliver real-time traffic and travel information to third parties and the public, and Analyse – a comprehensive back office data analysis capability.
UTMC systems commonly work with a diverse range of disparate sub-systems from a range of different manufacturers to achieve an integrated system environment. Examples include traffic signal control using SCOOT, integration of CCTV to monitor the network, car park occupancy information and Variable Message Signs to convey information to drivers. In addition, work is being undertaken to more closely align the UTMC Technical Specification with DATEX II, the European standard for traffic related data. This type of platform is therefore not only mature, but is also being used across the UK by the majority of highway authorities, and offers a route for emerging technologies to be used directly by traffic systems and to share information across a wide spectrum of stakeholders.
An example of the way in which UTMC systems offer a pathway to integrate different systems and allow future technologies to be more easily assimilated is with the use of air quality monitoring. In January 2017, Air Quality in London hit the headlines, with high pollution levels resulting in the poorest categorisation band of 10 being issued for the first time since the current system has been used. A major contributor to poor air quality in cities is recognised to come from vehicle emissions, although the reasons why these are worse at different times of the year are complex and include a range of climatic conditions. To tackle this, urban authorities have established air monitoring stations which provide data that can be used to identify pollution events and to allow forecasts to be produced to proactively warn of their likely occurrence. However, these systems tend to be large, often housed in a small cabin, which can be difficult to locate in an urban centre, where space adjacent to a highway can be at a premium. These systems are also expensive to purchase and to operate, with regular calibration and replacements required. These drawbacks, therefore limit the ability of most local authorities to deploy more than a handful of air quality stations across their road network. The result of this, is that the data produced can only provide broad indications of the environment, and lacks detail on a street by street basis. To overcome this, small roadside sensors can be used which give a resolution which is simply not possible with the traditional monitoring stations. Although these new sensors are not as accurate as full scale air monitoring stations, the technologies used are progressing continuously, so that measurements at parts per billion are now possible. These new generation sensors typically make use of the IoT principles discussed earlier, to use small devices that can be mounted onto existing street furniture. Because of this, it is possible to install many units across a city to gain a detailed understanding of the patterns that result in poor air quality events. These data streams can be fed into a UTMC system to allow traffic managers to understand the impact of traffic plans on the environment. This information can also be used proactively to trigger a range of actions (such as changing traffic plans) to reduce the impact that these events have, so could be used to reduce traffic flow in badly affected streets or to re-route traffic away from affected areas, before the situation becomes too serious. The system can then also be used to warn the public about air quality incidents, with online and VMS displays being used.
UTMC platforms are also already being used in areas with multiple stakeholders to provide operational benefits to the whole highway network. The responsibility for roads in England is broadly split between Highways England for motorways & trunk roads and local highway authorities for the rest of the road network. This often results in situations where the operation of one network can be affected across boundaries by another, including motorways affecting local roads, or roads in one highway authority area being affected by those in a neighbouring authority’s area. This type of cross boundary affect is particularly prevalent at motorway junctions, where local authority roads join into the Highways England network. Operational issues can then arise when congestion or incidents on the motorway occur, including warning drivers on the local road network not to join the motorway and with high volumes of diverting traffic from the motorway overwhelming the local road network. The Mott MacDonald Osprey system is used by Highways England for the South East UTMC deployment, where a number of junction dashboards have been implemented to bring together technology assets belonging to multiple stakeholders. This provides the control room operators with a view of the equipment around these busy junctions, allowing unified responses to a range of scenarios to be used irrespective of the different highway authorities affected. This closer integration for the operation of highway networks between neighbouring authorities is another benefit which can be delivered due to the unique flexibility that UTMC platforms provide.
With the future introduction of Connected and Autonomous Vehicles (CAV), there will be a requirement for data to pass from Vehicle to Vehicle (V2V) and to/from Vehicle to Infrastructure (V2I) (collectively referred to as V2X). The V2V connectivity will allow vehicles to inform or warn other vehicles around it on the road, for instance, to alert following vehicles that a car has had to apply its brakes hard. The V2I data exchange will allow traffic systems to inform vehicles of operational parameters or warnings, such as that the traffic signals ahead are currently red or that there are roadworks ahead. This connectivity will also allow vehicles to pass data back to the traffic systems, enabling the vehicles to become data probes for a range of criteria including actual journey time information, climatic measurements and warning of the occurrence of incidents. Although this type of deployment is currently being researched, the need for V2I connectivity will result in the requirement to find ways in which traffic systems can work co-operatively with individual vehicles. Traffic systems will also need to have the capability to work with a growing range of standalone sensors to get the most benefit out of these and to provide a pathway for emerging technologies to have the capability to inform the operation of the highway network in real-time. UTMC systems offer a unique platform which working with existing traffic systems also facilitate a pathway to allow emerging technologies to integrate effectively with them to the benefit of the whole community.