Overloaded vehicles refer to vehicles that exceed one or more of the mass limits in terms of Regulations 234 to 242 of the National Road Traffic Regulations (NRTR), 2000. The term chargeable refers to all vehicles that exceed the tolerance (a prosecution guideline) applied to all mass limits. If the mass of an axle, axle unit, vehicle or combination of vehicles exceeds one or more of the legal limits, the vehicle is overloaded, but only if the tolerance limit is exceeded can the driver/operator be prosecuted.
The Road Traffic Act, 1996 (Act No. 93 of 1996), and the Road Traffic Regulations, 2000, made under Section 75 of this Act determine the mass limits of vehicles used on public roads. The relevant regulations are Regulations 234 to 243.
Regulations 234 to 241 can be divided into two groups. The first group, namely Regulations 234; 235; 236; and 237 prescribe how the permissible maximum mass of an axle, an axle unit, a vehicle and a combination of vehicles respectively are determined. The subjects addressed by each regulation are as follows:
- Reg. 234: Permissible maximum axle mass; and
- Reg. 235: Permissible maximum axle unit mass.
- Reg. 236: Permissible maximum vehicle mass; and
- Reg. 237: Permissible maximum combination mass.
The regulations in this first group refer to regulations in the second group, namely Regulations 238 to 241, and prescribe which of the regulations in the second group of regulations are applicable in determining the permissible maximum mass of an axle, an axle unit, a vehicle or a combination of vehicles. In order to determine the permissible mass of an axle, an axle unit, etc. all the applicable regulations in the second group must be applied in respect of the vehicle concerned. The regulation that prescribes the lowest permissible mass is the one that determines the permissible maximum mass (legal mass) for an axle, axle unit, vehicle or combination of vehicles for the particular vehicle/combination of vehicles.
Regulations 238 to 241 can be classified as dealing with either safety issues or protection of the road infrastructure. Regulation 238 addresses safety and prescribes maximum masses according to the carrying capacity of the tyres of the vehicle. Regulation 239 also addresses safety and is concerned with the vehicle manufacturer's specification, that is, the maximum mass for which the vehicle and its axles were designed. Regulation 240 is chiefly concerned with the maximum mass that the road pavement (asphalt or concrete surface plus the underlying layers forming the structure of the road) can carry, while Regulation 241 is concerned with the maximum mass that can be carried by bridges and structures on consecutive axles or groups of axles. Regulations 240 and 241 therefore address the protection of the road infrastructure.
Depending on which regulation from this second group of regulations prescribed the lowest permissible mass, an overloaded vehicle can be classified as being overloaded in terms of either infrastructure damage or road safety issues.
Regulation 242 addresses the distribution of the massload on the vehicle by prescribing the maximum permissible difference between the wheel massloads on the left and right-hand side of a vehicle and the ratio between the mass of the steering axle of a vehicle and the mass of the rest of the axles of such a vehicle. This regulation thus also addresses road safety.
The last regulation, Regulation 243 determines the permissible maximum axle massloads of vehicles that are not fitted with pneumatic tyres.
The National Road Traffic Act (Act 93 of 1996) and the National Road Traffic Regulations (NRTR) , 2000 prescribe certain limitations on vehicle dimensions and axle and vehicle masses with which a vehicle using a public road must comply. However, certain vehicles and loads cannot be moved on public roads without exceeding the limitations in terms of the dimensions and/or mass as prescribed. Where such a vehicle or load cannot be dismantled, without disproportionate effort, expense or risk of damage, into units that can travel or be transported legally, it is classified as an abnormal load and is allowed to travel on public roads under an exemption permit issued in terms of Section 81 of the National Road Traffic Act. Exemption permits (EP) are issued by provincial permit offices in terms of guidelines developed by the Abnormal Loads Technical Committee (ALTC). A vehicle or a vehicle with its load that is considered to be indivisible can be abnormal either in terms of dimension or mass or both.
In this section information on abnormal permits issued by the nine provinces during the period 2001 to 2009 is presented. All the provinces use a computerised abnormal vehicle registration and permit system to register abnormal vehicles and to issue exemption permits. When this system is down, provinces issue manual permits, with the result that electronic data is usually not available for such periods. Periods for which no electronic data or only partial electronic data were available have been left blank the tables and figures in this section.
The number of abnormal load exemption permits issued per year in Mpumalanga province for the period 2001 to 2009 is presented in Table 1. These numbers include both mass and dimension permits.
As stated previously, a vehicle or a vehicle with its load that is considered to be indivisible can be abnormal either in terms of dimension or mass or both. In this section, information on mass permits is presented. In
Table 2 presents the mass permits issued per year in Mpumalanga Province for the period 2001 to 2009 are presented as a percentage of all exemption permits issued per year.
Figure 1 shows the overloaded E80s per vehicle class for the seven most common vehicle classes on an annual basis for the period 1995 to 2009 for Mpumalanga. The E80s were calculated using the Fourth Power Law and the overloaded E80s is arrived at by deducting the legal E80s for the specific vehicle from the total E80s calculated for the overloaded vehicle.
All the weighbridges on the N4, including the lay-bys are managed by Trans Africa Concessionaires (TRAC) under contract to SANRAL. TRAC's responsibilities include the maintenance and repairs of all the facilities and equipment and operations. Law enforcement functions are performed by law enforcement officials from the Mpumalanga Department of Public Works, Roads and Transport. Monitoring and evaluation of operations are carried out jointly by TRAC and the Department of Public Works, Roads and Transport.
The management of the provincial weighbridges is the responsibility of the Mpumalanga Department of Public Works, Roads and Transport. The Department's responsibilities include maintenance and repairs of all the facilities and equipment, operations, law enforcement functions and monitoring and evaluation of operations.
In addition to overload law enforcement, Road Traffic Quality System (RTQS) activities are also undertaken at some weighbridges. While the vehicles are at the weighbridge to be weighed a whole range of other offences can be attended to, such as the following:
The number of vehicles weighed in Mpumalanga province per annum is presented in table 1 below.
Table 1:Number of vehicles weighed in Mpumalanga Province (1995 -2009) per year
Organogram for Overloading Control and Management
Weigh data is available from 19 static weighbridges. These include provincial weighbridges, municipal weighbridges at testing stations that are also utilised for overload control, weighbridges that are operated by toll road concessionaires in cooperation with provincial road and law enforcement authorities and private weighbridges that are utilised for overload control.
The three weighbridge types are defined as follows:
The three main types of scales are as follows:
Other less common types of scales are single-deck scales or double-deck scales. Single-deck scales are usually 22 m long and can then weigh a whole vehicle combination in one go, but in order to weigh axles and axle units on such a scale, subtractive weighing has to be carried out. This type of scale is more suited for tare weighing or payload weighing and is used more in the commercial sector. Double-deck scales are rare and also require subtractive weighing when axles and axle units have to be weighed separately.
Weighbridges with a status of Operational are weighbridges that are currently being used. Those with a status of Non-operational are weighbridges currently not being used, but that can be made operational through maintenance or upgrading. Weighbridges with a status of In disuse are sites that have been abandoned. These are mostly sites that were equipped with single axle scales.
The Provincial Department of Roads and Transport has various weighing facilities in operations with several of them being operated by TRAC for the N4 toll road from Witbank to the Lebombo Border post in South Africa and from Ressano Garcia to Maputo on the Mozambiquan side of the border.
The control of overloading by the provincial authorities uses the various weighbridges located on the provincial and some municipal roads, while the control of overloading on the N4 toll road is handled by the toll concessionaire TRAC.
The weighbridge at Kwamhlanga on the R573 is operated by the acting manager of traffic in the Higveld Region, all the other weighbridges in Nkangala, the stations along the N4 as well as the Middelburg mobile unit, are operated by the TRAC (MDORT, 2006a).
Mpumalanga developed an Overload Control Strategy for the province during 2005 (CSIR, 2005). This strategy addresses the following aspects:
Abnormal loads are defined as loads, which are indivisible and are wider than 2.6 metres, higher than 4.3 metres, or exceed the maximum length of the carrying vehicle. Loads, which exceed the legal actual mass load, or gross combination mass permitted for the carrying vehicle, are also regarded as abnormal and subject to the abnormal load regulations (MDORT, 2006a).
The transport of abnormal loads is controlled from the Department of Roads and Transport offices in Nelspruit by means of the permit system, which forms a part of the control regulations of the National Road Traffic Act. The terms and conditions under which abnormal loads may be transported, are defined in the standards developed by CSIR- Transportek (MDORT, 2006a).
The conveyance of extra heavy loads under abnormal load permits is a highly specialised transport task, which is usually performed by specialist organisations with equipment capable of handling loads that range from 60-300 tons. The main commodities that are moved as abnormal loads are mobile cranes, earth moving machinery, steel structures and fabrications, heavy machinery, transformers, mining equipment and fully built up machines such as boats, harvesters, and military equipment (MDORT, 2006a).
TRAC the N4 concessionaire has no specific policies in place regarding the transportation of abnormal or dangerous loads. They do however have an Incident Management Strategy (IMS) that makes provision for general accident response teams which respond to any and all incidents, including those affected by dangerous goods.
There are also no specific routes that are prescribed for dangerous or abnormal loads, not from the provincial authority or the concessionaire. This is problematic since these vehicles can be extremely heavy and accidents can block entire routes for some time, thus they should definitely only travel on roads that are designed to carry heavy loads and have an action plan to deal with accidents involving dangerous load spills.
Heavy vehicle overloading is a major problem not only in Nkangala and Mpumalanga but in South Africa and the SADC region as a whole. Overloaded vehicles cause a disproportionately large amount of damage to the road network that in general is not receiving adequate attention in terms of road maintenance.
As indicated in Figure 1 it is estimated that about 60% of the damage to roads in South Africa is caused by overloaded heavy vehicles, representing a massive R700 to R800 million per annum. The result has been a steady deterioration of the road network (provincial roads in particular) in South Africa during the past 10 to 15 years. The premature destruction of the life-blood of the economy inevitably compromises road safety, which adds to the already high fatality rate. In addition, overloading results in unfair competition between road transport operators and between road and other modes of transport (MDORT, 2005: 1-1).
Figure 1: Overloading Damage
There are 16 weighbridges in Mpumalanga, six of them are located in Nkangala District Municipality (MDORT, 2006a):
The Mpumalanga Roads and Transport annual report 2004/5 states the following challenges and responses with regard to Law Enforcement for overloading:
Road Freight and specifically the overloading thereof is a major problem for the road surface conditions in the Nkangala District. According to the Mpumalanga Department of Roads and Transport a condition survey was conducted towards the end of 2004. This survey revealed that approximately 25% of the paved road network was in a poor condition. This is mainly attributed to a dramatic increase in coal haulage by road due to Eskom"s growing coal dependence in the area (MDORT, 2006a).
Heavy haulage by road has resulted in very poor road conditions, in some places (especially close to Eskom plants) to the extent that the paved surfaces of these roads have broken up completely. This has in turn forced Eskom to make use of longer alternative routes, which are consequently also suffering the degradation of the preferred routes (MDORT, 2006a).
The majority of the road network only has two major structural layers, which is not nearly adequate. Heavy haulage requires 3 to 4 structural layers along with durable surfacing (MDORT, 2006a).
Visual Condition of the Road Network
There is a very distinct trend towards worsening road conditions along the paved network in the Nkangala District. This is mainly due to the ever increasing amount of heavy vehicle traffic that flows along these roads. Some of the key reasons for this is large coal hauling operations in progress in the area, a nation wide trend towards the use of road freight rather than rail freight, and the high toll charges along the N4 corridor causing many of the freight companies to move their operations to lower class and lesser equipped provincial and local roads.
The responsibility for the total road network in Mpumalanga is shared among the three spheres of Government, as follows:
The responsibility for overload control in Mpumalanga lies with the Mpumalanga Provincial Government. The NRA and ANE are however responsible to TRAC for control of overloading on the toll road to prevent above normal deterioration of the road surface. The principle adopted for the overload control project is that the NRA provides the MPG with the infrastructure and the Operator plus funds for the Traffic officers enabling them to effectively control overloading. Maximum control measures have been built into the agreement with the MPG to ensure efficient control (MDOPWRT, 2004: 2-14).
Mpumalanga Dept. of Roads & Transport
Efficiency in the provision, maintenance and operation of the primary economic road infrastructure network will be facilitated by a professionally managed Roads Agency (SANRAL) with a Board of Control consisting mainly of users from the private sector. The primary road network should preferably be financed through dedicated levy on fuel and toll charges. Further innovative ways of securing finance for the development of road infrastructure will be explored, such as Build-Operate-Transfer (BOT) or Fund-Rehabilitate-Operate-Maintain (FROM). Other rural and inter-city and urban infrastructure will be the responsibility of provincial and local authorities and be funded from a variety of tax sources (NDOT, 2007: 146). The Nkangala District Municipality annually spends approximately R49 Million on Roads and Stormwater infrastructure, this amount is divided between the different local municipalities within Nkangala as set out in Table 1 below.
Distribution of Roads Expenditure
As can be seen in Table 1 above a major imbalance is evident in the distribution of funds for roads and stormwater infrastructure. Even more alarming is the fact that one of the lowest figures (Emalahleni Municipality) relates to an area that has the largest need for funds to upgrade and maintain their road infrastructure. The Emalahleni region is the area in Nkangala where the largest amount of coal hauling takes place.
This section deals with the extent of overloading and information on the number of vehicles weighed, overloaded and chargeable in the province. The statistics presented in this section are based on all of the available data, which includes the electronic and summary data.
Figure 1 shows the number of vehicles that have been weighed annually in Mpumalanga.
Figure 1 shows the number of vehicles weighed, overloaded and chargeable per province summarised per annum. The number of vehicles overloaded and chargeable is also shown as a percentage of the number of vehicles weighed. The same information is illustrated in Figure 2.
Table 1:Vehicles weighed, overloaded and chargeable per annum in Mpumalanga
This section deals with the degree of overloading and presents information on average overloads per overloaded vehicle and per axle type, namely single axles, tandem axle units and tridem axle units. The statistics presented in this section are based on the available electronic data only.
Figure 2 shows the trend in the average overload per overloaded vehicle in Mpumalanga for the period 1995 to 2009.
Table 2 and Figure 3 shows the trend in the average percentage overloads on single axles, tandem axle units and tridem axle units in Mpumalanga for the period 1995 to 2009.
In Table 3 and Figure 4, the distribution of vehicle overloads in Mpumalanga is illustrated by showing the percentage of overloaded vehicles falling in each overload band per year for the period 1995 to 2009.
This section presents information on overloaded vehicles per vehicle class. Seven vehicle classes, representing more than 90 % of all overloaded vehicles, are reported on separately, while the remaining classes are grouped together as "other".
Figure 5 shows the percentage of overloaded vehicles per class for the period 1995 to 2009.
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