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Improving roadworks' safety & traffic management

Traffic safety cone

Road authorities around the world are seeking to improve safety at roadwork sites.

In this article, Kim Thomas, Aurecon’s Intelligent Transport Systems Leader for ANZ, discusses a recent research study on potential technologies and applications that can be implemented to help achieve zero harm at roadworks sites.

Ensuring the safety of contractors, road users and traffic controllers at roadworks sites is of major importance to road authorities, as part of their duty of care to employees and the broader community. Minimising the impact of roadworks on road users is another challenge. Road users experience frustration around roadwork sites when signage is not updated to match the current conditions, particularly after hours. As a result, compliance with the signage, particularly speed limits, is poor, making the roadworks environment less safe.

The 3 E’s framework

The 3 E’s framework is an effective approach to improve safety and traffic management at roadwork sites, combining engineering, enforcement and education to deliver improved operations at roadworks sites. This approach has been adopted by agencies such as the Queensland Department of Transport and Main Roads (TMR).

Intelligent Transport Systems (ITS) are in a position to support both the engineering and enforcement action areas:

  • There is great potential to be innovative in the use of traffic control and information devices using emerging technologies
  • Using ITS, it is possible to update electronic signage so that the guidance to road users is consistent with the roadwork site conditions, thereby restoring driver confidence
  • ITS can be implemented for speed enforcement and for in-vehicle provision of speed limit reminders to improve speed compliance
  • ITS, supported by on site and remote telecommunications, is available to support monitoring of roadworks sites for enforcement of roadwork signage practice

The view from industry

TMR is actively encouraging traffic management and construction organisations to innovate in the development and implementation of Traffic Management Plans (TMPs) as part of Traffic Guidance Schemes (TGSs), including making use of ITS solutions to support safer management of roadworks sites. Traffic management and construction organisations tend to be reluctant to innovate, partly due to concerns about risk, and partly because of the perceived cost of implementing changes to existing practices. Organisations are concerned that the costs of changing the traffic management approach may result in the loss of a bid. For this reason, traffic management and construction organisations are pushing for TMR to update standards as a way of directing them to change their practices to ensure fairness across the industry. This will have direct safety and financial benefit to the industry as the TMPs that are currently set up tend to be excessive and incur more expense than is necessary.

TMR has reviewed its contractual framework and is working within its regional management structure to ensure the updated terms are used on new projects. Various specifications have been developed and these will also be rolled out to the industry.

Typically, 80% of benefits come from 20% of the actions. In the roadworks safety context, the best safety and operational improvements can be gained by:

  • Catching and prosecuting the major offenders – in particular those heavy vehicle drivers that exceed speed limits by over 20 km/h
  • Efficiently and accurately operating the roadworks site’s affected traffic, including returning the road to normal operations when the site is not active

Catching offenders

Enforcement is the only really effective deterrent to drivers. The police staff deployed to roadworks sites have to be experienced, senior staff, who are in high demand for a wide range of other issues. As a result, Police Services lack the resources to support speed enforcement at roadworks at a comprehensive or sustained level.

To augment police resources, it is essential to explore technology solutions. To roll out speed cameras on a large scale, some form of certification will be required to ensure chain of evidence and equipment accuracy requirements are met. Setting up systems and specifications to allow for routine rollout of temporary speed camera sites on road projects is essential. Once these can be implemented, support through education in the form of a publicity campaign will greatly improve speed compliance.

Efficient operations

Roadworks site signage needs to be consistent with the actual conditions on the site. Once road users know that they can trust the signage at a roadworks site, they will be more likely to obey speed limits, and behave more consistently at the end to the site. To ensure signage is correct, it needs to be:

  • Planned well under a Traffic Guidance Scheme
  • Sited in locations suited for flexible provision of information, e.g. making provision for an electronic variable message sign (VMS) to operate as a messaging sign and as a variable speed limit sign, as the site evolves.  
  • Monitored regularly to ensure the signs are displaying the correct information, consistent with the conditions at the roadworks site.
  • Updated in real time, consistent with site conditions, including site closures at the end of the day

Traffic management coneSolutions

Technology solutions are easy to develop once the problem is well defined. The burgeoning access to high bandwidth communications is a major enabler for ITS surveillance and control applications at roadworks. A combination of technology solutions and business process improvements is expected to produce the greatest benefits. These are explored further below.

Risk elimination

In a presentation to the IRF/Roads Australia conference in Sydney, May 2015, Craig Moran of New South Wales Roads and Maritime Services (RMS) noted that RMS had assessed the hazards around operating traffic in a roadworks environment and determined that in various instances, the risk is too high. As a result, the decision has been made to schedule road closures for specific maintenance activities, providing driver information and alerts well ahead of the event, and routing traffic as well as possible around the site.

There are unexpected benefits of this approach as maintenance staff report that they are able to focus better on their tasks when they don’t have to worry about traffic. This has resulted in improved efficiencies and cost savings.

Upgrading equipment

Some equipment such as portable traffic signals have fallen significantly behind the times in terms of functionality and safety outcomes. This is in part due to the high level of concern around safety of these devices, particularly for control of intersections. Another element is the lack of update of the national and state based standards, again due to perceived risk. Ironically, this lack of change means that some risks that should be eliminated using modern detection technologies are not.

Agencies are encouraged to take the leap to upgrade their system specifications to require better safety and operational performance, and to push for upgrades to the national standards.

Changing the use of existing equipment

There is great potential to gain safety and operational benefits from making use of a variable message sign (VMS) to provide for variable speed limit, textual and pictographic messages. A traffic guidance scheme with supporting traffic management plans can then be developed to place the VMS at a location and make use of it in different ways as the roadworks site requirements evolve. The ability to control these signs remotely is key to achieving safety and operational benefits.

Similarly, there is an emerging system that is being tested in Christchurch, New Zealand for the provision of information on street signs on drivers’ smart phones as they approach a sign. Beacons broadcast information about the signage which is received and acted on using a smart phone app. This functionality could be adapted to be a roadworks speed advisory system with geofencing provided by placing beacons at the site. To minimise driver distraction, an audible message would be provided. While this concept doesn't provide for enforcement of speeding by truck drivers, it does facilitate self-policing, which has been supported by the larger trucking entities in other contexts.

Using cheap, replaceable equipment

It is desirable to provide for CCTV coverage of signs or control devices but the cost of procuring a robust CCTV at a roadworks site makes it difficult to provide multiple CCTVs. Cheap options like the Raspberry Pi mini PC are worth trialling in a site environment. These can be set up by children for nature photography including detection of motion. There is a growing community of users of these devices with new functionality available all the time. At AUD35 per unit, if one gets destroyed, it can be replaced very cheaply.

Adoption of technologies from other industries

The mining industry makes use of remote communications equipment routinely during mine development and operations. This equipment has been developed and tested to rigorous operational and safety standards, and the road industry is in a position to benefit from the investment that the mining industry has made in this area.

There is great potential to use equipment designed for the mining industry to support remote communications and power requirements. This type of equipment is extremely tough and well suited to a dusty roadworks environment.

Remote oversight using apps

It is highly desirable that traffic controllers and other authorised site staff are able to remotely monitor and control electronic traffic devices on site using a tablet based app. For optimal usability and ongoing system improvements, this interface should be in the form of a configurable schematic. An example of the style of proposed user interface is presented below (Figure 1).

Schematic for roadworks site management app

Figure 1: Schematic for roadworks site management app.*

Using a tablet or smart phone for site control provides enormous flexibility as the equipment and technology evolves. An app is easy to maintain and update in comparison to traditional software.

Extending this concept further, the app could be set up to:

  • Provide information on all electronic traffic control devices on the site
  • Provide the ability to view footage from any site CCTV cameras
  • Be used to implement and update TMPs on the fly (as noted in 2.1.2)
  • Receive location data from cooperative ITS (C-ITS) equipment located in site plant vehicles
  • Provide safety alerts to traffic controllers if they are straying into unsafe areas (e.g. too close to plant vehicles)
  • Allow access to the app at remote locations e.g. enforcement agencies

The benefits of using an app include:

  • Having an easy overview of the roadworks site using a simple schematic
  • Easier and safer remote configuration of equipment – easier to understand the equipment context
  • Safer remote operational access for traffic controllers
  • Cost savings as traffic management and impacts are reduced by allowing for remote control of devices
  • Better situational awareness for traffic control staff

This model means that traffic controllers would have considerably less exposure to both plant and road users when changing or operating signage, and one controller would be in a position to operate multiple devices efficiently.

There are emerging technologies to support this functionality – handheld devices such as ruggedised tablets are already able to use WiFi or connect to 3G/4G telecommunications. These can connect to and control electronic devices on site.

Similarly, a number of sign suppliers are providing GPS tracking of signage via web sites, including display of a sign’s current status.

Implementation considerations

Safety Integrity Level (SIL) ratings for devices vs type approvals

A review was undertaken on the pros and cons of requiring a Safety Integrity Level (SIL) rating for devices to be used at roadworks sites, e.g. portable traffic signals. SIL assessments are expensive to implement and largely unrealistic as SIL ratings are best applied to automated systems where there is very little human involvement. In a roadworks site, this would be impossible to achieve. 

As a result, a type approval process is recommended for innovative roadworks equipment. A national body is in the process of being set up to allow states to adopt type approvals completed by other states. This will significantly reduce costs for equipment developers.

Performance specifications 

The US Department of Defence has adopted a performance specification based model for all its procurement activities. A draft portable traffic signal specification has been set up using this framework.

This approach specifies the required outcomes, but does not direct suppliers how to achieve the outcome. This enables suppliers to innovate and develop new and better solutions that meet operational needs. 

A balanced approach is essential. Where safety is concerned, some requirements may need to be inflexible and very detailed. 

Data dictionaries and protocols

One of the concerns around trying to implement an app-based control system is that there are multiple suppliers for the traffic control/surveillance devices, each providing systems of varying levels of sophistication. 

To facilitate app and system compatibility, the recommended approach is to develop a data dictionary with a standard set of names, definitions, attributes and actions for the various facets of a system: data flows; databases, entities and processes. Data dictionaries can be very difficult to get agreed, with greater difficulty the more stakeholders are involved.

The National ITS Architecture development and associated harmonisation of standards has potential to deliver a data dictionary, but this will take a number of years. In the meantime, it is likely that one or a few suppliers will end up dominating this industry with their systems/ protocols becoming the de facto standard.

The future

Autonomous vehicles are projected to be in the marketplace from around 2020. Beacon-based applications have great potential into the future, where similar beacons will be in a position to inform vehicles about the speed limit so that all autonomous or C-ITS fitted vehicles will pass through roadworks sites at the appropriate speeds.

With the increase in the vehicle population of these types of vehicles, it will become even more important that signage and control devices are set up consistent with the roadworks environment.

* The original image was sourced from www.altustraffic.com.au, viewed 9 July 2015.

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