Introduction and Background
Vehicle related fatalities and injuries are some of the most important concerns to the Health and Safety Officer in the Mining Industry. There is little to prevent the risk of underground tremors and impacts from forces of nature, yet vehicle related incidents are much more preventable. Speed management should form part of the overall risk management approach that mining operations should have in place and actively promote. Mine management has the responsibility to ensure that work areas, such as roads, are safe.
In this section we would like to consider how measures for traffic calming can reduce vehicle related accidents at our mines.
What is Traffic Calming?
Traffic Calming or speed calming is the description most often used when referring to limiting vehicle speed as an important part of traffic control. The aim of speed management is to minimise risks with driving at speeds that are inappropriate for prevailing conditions.
This is usually achieved by establishing safe speed zones and developing measures to ensure compliance with speed limits.
Why is Traffic Calming so important on the Mine?
The mining site and operational activities on the mine require several modes of transport used in close vicinity of one another. Service, utility, maintenance, contractors, fuel, powder, supervisor and other over the road trucks enter mine property every day.
The nature and size of the equipment present some unique dangers. Large mining equipment has blind areas where smaller vehicles cannot be seen.
Principles to consider for standards in Traffic Calming
It is appropriate to reflect on the measured used in the design of traffic calming in Australia. The Australian Standard AS 1742.4:1999 Manual of uniform traffic control devices focuses on principles for traffic calming.
Principles to consider are:
- speed limits shall be capable of being practically and equitably enforced by use of speed zones of adequate length, by limiting speed limit changes and by clarity and frequency of sign posting — in other words, not too many changes in speed limit over a short distance;
- the speed limit shall not be so low that a significant number of drivers will ignore it;
- speed limits shall not be applied specifically for the purpose of compensating for isolated geometric deficiencies — in other words, build well-designed roads so that low speed limits do not have to be used to compensate for design faults (e.g. corners that are too tight); and
- all signposted speed limits shall be in multiples of 10 km/h. When determining appropriate speed limits on mine sites, the following points should be considered.
What should the speed limit be at mines?
There is no set speed limit for all mines and all conditions. Speed limits need to be sensible and practicable, or drivers will be tempted to break them.
Speed limits need to be appropriate for:
- the vehicles using the route;
- the types of load they carry and how they carry them;
- the driving surface;
- the route layout, including how tight the bends are, and visibility at junctions;
- hazards along the way;
- work being done on or near the route.
Common problems with speed limits are that they are inappropriate, poorly signed, or not enforced. They are often arrived at by guesswork, and may be unreasonable and difficult to enforce in practice. Often, vehicle speedometers don’t work effectively at low speeds. Some internal site transport vehicles don’t have speedometers at all.
To decide an appropriate speed limit, consider the route layout and road usage. For example, lower speeds will be appropriate where pedestrians are present or where fork-lift trucks and road-going vehicles share the roadway. Different limits may be needed for different parts of the site. Consider using professional advice.
It is suggested that the following factors be taken into consideration:
- The speed environment is determined by the elements of the road and traffic environment that influence a driver’s perception of an appropriate operating speed.
- The road’s crash history should be taken into account when assessing the appropriate speed limit.
- The function and purpose of a road will provide some guidance as to the likely speed limit that drivers would expect to see.
- In addition to set speed zones, advisory speed signs can also be used at specific locations on sealed roads to indicate to motorists that a reduced operating speed is more appropriate.
- Examples include at curves, steep crests or where the road conditions ahead dictate the need to drive at a lower speed.
Criteria for Establishing Speed Zones
Which criteria are most important for the Mine Management when establishing speed zones?
- Set speed limits to provide a reasonable balance between an acceptable level of service and the driver’s perception of the road environment.
- Speed limits should be logical, safe, practical and achievable, and reflect the condition of the road infrastructure to which they apply.
- By imposing a speed limit lower than what the road configuration allows, some drivers will disregard the posted speed limit and drive at a speed that they perceive as appropriate.
- Speed limits below 10 km/h are hard to comply with and not measurable by vehicle speedometers.
- Such impractical limits convey the wrong message to road users.
- It is important to minimise the number of speed limits within an area to three or four (e.g. 10, 20, 40, 60 km/h).
The importance of Stopping Distance in Establishing Speed Zones
An important aspect in speed management is to consider stopping distances. The stopping distance is the distance that a vehicle travels from the moment the external stimulus is within a drivers’ field of vision to its complete stop, in a safe manner.
It comprises the reaction distance (related to reaction time) and braking distance. The reaction time depends on factors such as physical or psychological state of the drivers, available lighting and distractions.
The braking distance is determined by the vehicle type, operating speed, longitudinal friction factor and longitudinal grade of the road. It is commonly understood that reducing speed has a positive effect on traffic safety.
Even at what are perceived as low speeds, such as 60 km/h, the reduction in stopping distance between 60 km/h and 40 km/h for cars is 32 m, which can make a huge difference between a vehicle being able to stop safely and being involved in a crash.
Mining Production v Safety of Moving Traffic
Mine management is well aware that vehicle speeds play an important role in productivity and production results, especially for operations that depend on tight trucking cycles such as direct ore feed. Speed calming is important but the mine must also weigh against this the ability to deliver sustainable productivity.
It is suggested that the safety aspects of various operating speeds be carefully considered together with implications for production.
Separating light vehicle movements from heavy vehicles will significantly reduce the risk of vehicles being involved in incidents and the speeds on the roads can be set accordingly.
Signage and Traffic Calming
How can we use signage correctly as a measurement for traffic Calming?
- Speed limit signs should be erected on the left side of the carriageway.
- Ideally, speed signs should be installed in pairs on both sides of the road when a change of speed zone is required and, normally, no other sign should be erected on any post carrying a speed limit sign.
- It is also suggested that speed signs used on mine sites should be highly visible in the largest legal sign size.
- On long stretches of road, repeater speed signs should be erected at regular intervals of 500m or less if necessitated by prevailing conditions.
Speed Zone Mapping and Education
Speed zones maps are also a useful tool to familiarise drivers with an operation’s speed environment. They should be used for driver training, advising drivers of any speed limit changes, such as temporary speed limits during road works, and re-installing signs that have been damaged and removed. The maps should be updated whenever speed limits are changed.
Traffic Calming in High pedestrian activity areas at the Mine
Special consideration should be given to areas with high levels of interaction between pedestrians and various vehicle types, such as administration areas, workshops and processing plants.
Implement a low speed limit environment to ensure the traffic risk at such locations is minimised. The speed of 10 km/h is generally accepted as a safe speed for areas of high levels of interaction between vehicles and pedestrians. The low speed also reduces the possibility of contact between the vehicle and pedestrians.
Best Practise Guidelines
We would like to share a few guidelines to enhance safety:
- Designate specific roadways or provide alternate routes for light duty vehicles in high activity or congested areas.
- Adhere to all traffic rules, signals, speed limits and warnings.
- Require all vehicles that enter the mining area to be equipped with buggy whips and/or strobe lights.
- Keep headlights on during daylight hours to enhance visibility.
- Design traffic patterns to reduce exposure to blindside hazards.
- Mining equipment always has the right of way (except emergency vehicles).
- When stopping or attempting to board a piece of mining equipment:
- Always communicate your intentions by radio prior to approaching and wait for positive response
- Always ensure equipment is stopped in a safe area
- Always approach on the operator’s side
- Always make eye contact or use hand signals before boarding equipment and again, wait for positive response.
Fleet Management Technology and Traffic Calming at Mines
Mine management is recognizing the benefits of modern fleet management technology in measuring and enforcing traffic calming measures at the mines. We would like to reflect on just a few of these benefits:
Ctrack, a division of DigiCore Holdings Ltd, a JSE-listed entity, develops and uses the most technologically-advanced vehicle monitoring and fleet management systems to assist some of the largest miners in ensuring that all vehicles that operate on a mine – from plant equipment to trucks to company cars – do so as safely and cost efficiently as possible. By using cellular and satellite technology Ctrack ensures communication is continuous no matter how remote the location.
“On the mines, we make use of server-based software that provides our mining clients with essential and relevant real time monitoring. Having access to this information enables the mine to take corrective action immediately, should there be a problem with one of the vehicles or drivers,” explains Marcel Blokland, sales director of Ctrack Fleet Management.
The versatility of the system enables it to be customised for each client’s safety requirements and monitoring risk protocol. These could include monitoring different aspects of a vehicle and its driver, such as seatbelt compliance, strobe light activation, speed zone monitoring, use of brakes, RPM, fuel consumption and the vehicle’s carbon footprint.
The system can identify each driver and restrict him from driving vehicles which he is not qualified to operate. The mine management team can also interrogate the recorded data should they need to investigate an incident involving one of the vehicles or drivers on the mine,” states Blokland.
Compliance and Enforcement of Measures for Traffic Calming
A comprehensive speed management strategy is only partly achieved if there are no effective measures in place to ensure compliance with the requirements.
Site management can implement a number of measures to work towards lowering the risks associated with speeding and unsafe driving behaviour, and encourage compliance with the applicable road rules.
Such measures include procedures, engineering modifications and behavioural modification.
The following list of possible measures to ensure compliance is by no means exhaustive:
- Establish realistic and simple speed zones that are easy to comply with.
- Enforcement and disciplinary actions should be used as a last resort measure to show management considers speeding to be an unnecessary risk-taking behaviour that will not be tolerated.
- Regular activities should be undertaken to promote the importance of compliance with speed limits and the serious consequences associated with speeding.
- Engineering measures can be used to physically slow traffic (e.g. narrowing sections of roads, installing speed humps, using in vehicle speed monitoring systems).
- Speed checks can be used to modify road user’s behaviour, either as random handheld radar checks or by using portable speed radars with variable message signs to give feedback to drivers about their speed. [Fleet management technology could be an important scientific tool]
- For its part, mine management should to ensure that vehicles provided are fit for purpose, roads and road infrastructure are constructed and maintained in a safe condition, and there are no unsafe or impractical speed limits in place.
- Mine management should also ensure that there are no work pressures that would require drivers to speed and the road environment is forgiving to those who make genuine mistakes and lose control of their vehicles.
Important aspects to consider when establishing Traffic Calming measures
Fixed traffic calming features that stop drivers travelling too quickly are often regarded as some of the best ways to ensure speed management. Examples include speed humps, narrowing routes by use of bollards, raised kerbs or chicanes, and ‘rumble’ strips or areas.
This, as with every other measure should however be implemented with caution and recognizing specific hazards under those very unique circumstances.
Speed humps are often used to control speed but need to be used with care as they can create hazards of their own. The wrong traffic calming feature can sometimes increase risk, eg by affecting the stability of vehicles or less-secure loads. You should assess the various features available and select those most appropriate for the traffic using your site.
Traffic calming measures should be clearly visible. Many features can be lit or made reflective.
[Credit also for information first published in the Western Australian Department of Consumer and Employment Protection’s MineSafe Western Australia Magazine]