Raising the alarm

26 July 2023

Accidents involving workers and moving vehicles have increased at an alarming rate. Advances in technology can alert workers to dangers and provide a level of protection in hazardous areas. Jacqui McLaughlin looks at the benefits of proximity warning systems.

PROXIMITY WARNING systems play a crucial role in preventing accidents involving people and plant. 

With technology as the catalyst, proximity warning systems are constantly evolving to adapt to real-world industrial environments to maximise protection and minimise operational downtime. 

There is a plethora of new detection technologies available in the market, so how do you know which proximity warning system is the most effective for your risk environment? 

Reactec believes in a prevention engineering approach to workplace health and safety risks. The Edinburgh-based tech firm have developed a powerful combination of wearable devices and cloud-based analytics for creating safer and healthier work environments by design. 

Proximity hazards

Accidents involving pedestrians in close proximity to moving vehicles and machinery are increasing at an alarming rate across multiple sectors. Each year, over 1,300 accidents are caused between pedestrians and forklifts (1), while in the construction industry, being struck by a moving vehicle or contact with unguarded machinery, rank among the highest cause of fatalities (2).

There are also significant financial implications for employers that fail to reduce the risk from proximity to hazards within the workplace. Substantial fines and penalties are imposed on employers that are not doing enough to safeguard workers who work in close proximity with recognisable hazards. In a reported incident in 2023, a company was fined £800,000 following the death of an HGV driver who was tragically struck by a forklift (3).

The data would suggest that traditional methods of safely segregating people and plant are vulnerable or inadequate, leading to employers giving greater consideration to adopting proximity warning technologies to mitigate this critical risk to worker safety. 

Proximity Warning Systems

So, what is a proximity warning system? A report commissioned by the Scottish Road Research Board (SRRB) defines a proximity warning system as detection technology which uses an audible, visual or haptic alert to indicate when an invisible, digital, exclusion zone centred around a restricted area or plant has been breached in real-time (4).

While many detection technologies exist, they are all underpinned by the primary objective to prevent accidents between people and plant, vehicles, or machinery. The SRRB report included an assessment of various proximity warning technologies in 2018. 

It was evident from the report that proximity warning systems are generally divided into three distinct parts; the pedestrian alert, driver receiver signals and analytical reporting. 

The report identified that radio frequency identification was among the most used technology to identify pedestrian workers on site. RFID tags worn on the body, or integrated as part of PPE, detect the movement of pedestrian workers in proximity to operating vehicles and active machinery. While the driver notification technology varied from flashing beacons to cab fitted CCTV and machine operator control units to indicate a vehicle exclusion zone breach. 

Pros and cons

All proximity warning systems have notable strengths and drawbacks. Fundamentally, the proximity warning systems reviewed in 2018 relied on the pedestrian, including any site visitors, to always wear an RFID personnel tag to ensure their movements were detected. The technology needed to be non-intrusive and simple to use to increase the likelihood of user adoption. 

Furthermore, the report highlighted that drivers and machine operators could be prone to sensory overload. Arguably, proximity warning systems which comprise of camera display units, flashing lights and sound alarms, could contribute to an overstimulated operating environment. 

Similarly, it was suggested that proximity warning systems could replace the vigilance of drivers who become complacent and over-reliant on the use of these visual and audible alarm systems. 

In contrast, the report highlighted that proximity warning systems are designed to offer an additional layer of protection by improving situational awareness for both pedestrian workers and machine operators. 

The report emphasised that proximity warning systems can augment existing Safe Systems of Work. For instance, sophisticated proximity warning systems which recorded actionable data on near-miss occurrences demonstrated the potential for employers to identify site hotspots and implement preventive measures to refine controls. 

Emerging technologies

More recent advances in proximity detection technologies include the introduction of ultrawide-band (UWB) technology and cameras supported with Artificial Intelligence. 

Ultra-wideband is an effective short-range radio communications technology which offers high accuracy and low latency. The technology is proving very effective for precise location and tracking applications of moving objects. Like the more established RFID technology, UWB based systems require a device for the pedestrian, which brings the benefit of being able to identify the pedestrian. The advantages of UWB over RFID is its detection performance and the fact that there is an inherent communication protocol between a pedestrian and hazard, supporting more sophisticated implementations.

AI-enabled cameras are demonstrating the potential to identify objects as humans and trigger an automated and appropriate response from an exclusion zone breach. The distinct advantage of such systems is the ability to determine a pedestrian based on AI alone without the need for a device on the pedestrian. With that comes the drawback of not having identifying data on the pedestrian. 

Adapting to real-world scenarios

Whereas each technology has its advantages and limitations, the answer to which proximity detection capability is right for your organisation, oftens depends on very specific operating and site requirements. 

In some industries, activities involving people and machinery or vehicles inevitably overlap. Within the construction industry for example, authorised closed working is necessary for banksman and slinger activities when supporting lifting operations. 

Furthermore, pedestrians maybe within close proximity to moving vehicles but working in a safe zone, protected by other physical barriers including bollards, fencing or suspended gantries. 

In both scenarios, proximity warning systems must be sophisticated enough to recognise safe and authorised close working, to prevent false alerts. 

It’s often the case that workers can switch between pedestrian and driver roles during the same shift. Therefore, how can proximity warning systems continue to provide adequate protection from a driver once they exit their vehicle? 

A key consideration for selecting a proximity warning system is choosing a solution which can adapt to real-world work situations, while continuing to offer full protection. 

Reactec benefits analysis

Reactec worked closely with duty holders and contractors in the construction industry to develop a highly effective and fit for purpose proximity warning system; R-Link. 

Reactec have integrated into a third generation workplace wearable, the R-Link watch, UWB proximity detection to add to other sensors detecting risks such as exposure to vibration and slips, trips and falls. 

A second device, the R-Link beacon, is flexibly mounted onto vehicles or along the perimeter of a restricted area, to alert the R-Link watch wearer of close proximity to an operating hazard. Data collected by the watch is automatically, securely transmitted and stored in the cloud-based Reactec Analytics to produce heatmaps and intelligent data insight to prevent future accidents. 

Ferrovial Construction adopted R-Link following a successful trial of the technology in November 2022. The trial involved two separate contractors, over two nights, operating at Heathrow airport. 

On the first night, a ‘blind trial’ was implemented where contractors wore R-Link watches and were instructed to carry out their work as normal while the alerts from the R-Link watch were switched off. Whilst not alerting the wearers, the R-Link watches still collected data on an exclusion zone breach. 

During the following night shift, a different contractor wore R-Link and were trained to respond to alerts from the watch and safely move away from the proximity hazard. 

As a result, the alerted workers recorded 82% less incursion time than the unalerted workers to the same type of moving vehicles on site.

This example was the highest reduction seen, but generally, Reactec has found that the amount of interaction between pedestrians and plant is reduced by at least 50% once workers are alerted.

The right choice

As technology advances at a rapid rate, employers are becoming better equipped to mitigate and prevent common threats to worker health and safety. 

At its core, proximity warning systems protect teams from moving vehicles, unguarded machinery and unsafe areas in real-time.

The emergence of connected worker technologies, however, are empowering employers to make data-driven decisions to augment existing safe systems of work and prevent future incidents. 

Choosing which proximity warning system is right for you requires 1). an assessment of the pros and cons of each detection capability and 2). a determination of how the solution would adapt to real-world work scenarios within your own risk environment. 

Technology must be highly configurable, to changing site layouts and worker’s roles, while offering full protection without slowing down operations. When it comes to choosing a proximity warning system, customisation is key.


  1. British Safety Council. A very costly forklift accident. (Accessed Online, 21 July 2023)

  2. HSE Construction Statistics in Great Britain 2022. (Accessed Online, 21 July 2023)

  3. HSM Webinar – Advanced Proximity Warning Systems: Key considerations from adopting innovative technology to prevent accidents involving people and plant. (Accessed Online, 21 July 2023)

  4. JACOBS Research (2018). Site Proximity Warning Systems. Research prepared for the Scottish Road Research Board. (Accessed Online, 17 July 2023):

Jacqui McLaughlin is CEO at Reactec. For more information, visit