The Heavy Vehicle National Law (HVNL) is the primary law governing loading requirements on heavy vehicles. Heavy vehicles are defined as vehicles that exceed 4.5 tonne gross vehicle mass.[1] HVNL aims to improve public safety by reducing risks arising from insecure loads. This is achieved by imposing requirements for securing loads on heavy vehicles. Insecure loads can dislodge from the vehicle during movement and can cause a serious injury or death.

**Duty**

Pursuant to section 111 of the HVNL a person who drives a heavy vehicle or permits another person to drive, has a duty to ensure the vehicle and its load complies with the loading requirements applying to the vehicle.

Under the Chain of Responsibility this duty can also extend to other parties in the supply chain, which could include the consignor, consignee, transport operator, loader, packer, or loading manager.[2]

**Categories of Breaches**

There are 3 categories of breaches of loading requirements which include:

- Minor Risk Breach
- Substantial Risk Breach
- Severe Risk Breach

Minor risk breach is the least severe category of risk breach, while severe risk breach is the most severe category of risk breach. The difference in severity between categories depends upon the severity of the safety risk and the severity of risk of damage to road infrastructure or adverse effect on public amenity from the breach.[3]

Contraventions can be detected by the National Heavy Vehicle Regulator (NHVR) or Victoria Police by checking of compliance to loading requirements. This may be achieved by inspecting vehicles and equipment, taking measurements for load restraint calculations, CCTV, photographs and witnesses statements.

**Loading Requirements**

To comply with the above duty, parties must ensure the vehicle and load complies with the loading requirements, which are:

- A load on a heavy vehicle must not be placed in a way that makes the vehicle unstable or unsafe.
- A load on a heavy vehicle must be secured so it is unlikely to fall or dislodge from the vehicle.
- An appropriate method must be used to restrain the load on a heavy vehicle.[4]

**Loading Performance Standards**

Duty holders are also required to ensure the vehicle and load complies with the loading performance standards, which are:

##### Preventing the Movement of Load

A load on a heavy vehicle must be restrained by a load restraint system that prevents the load from moving in relation to the heavy vehicle.[5] However, there are exceptions which allow load movement in the following circumstances:

- If the vehicle’s stability and weight distribution are not adversely affected by the movement and
- The load does not become dislodged from the vehicle

Examples of permitted load movement under the regulations include:

- Load contained within the sides or enclosure that is restrained horizontally but may move vertically
- A bulk liquid load contained within the sides or enclosure of the heavy vehicle

**Capable of Withstanding the Forces**

The second performance standard requires duty holders to ensure the load restraint system is capable of withstanding the following forces:__[6]__

- 0.8g deceleration in a forward direction
- 0.5g deceleration in a rearward direction
- 0.5g acceleration in a lateral direction
- 0.2g acceleration in a vertical direction
__if friction or limited vertical displacement is relied upon__

**Complying with the Duties**

The Load Restraint Guide 2018 published by the National Transport Commission (NTC) is a publicly available document that can assist duty holders to comply with their duties in relation to loading requirements. This guide provides information and examples on how vehicles and loads can be restrained to comply with the loading performance standards.

Duty holders can also comply with their duties by certifying their load restraint system by an engineer to comply with the loading requirements.[7]

**How Angle Effect Can Contribute to Contraventions**

There are several methods to restrain loads, which include:

- Using tie-down lashings to clamp the load onto the vehicle
- Using the vehicle body to contain the load
- Blocking the load against the vehicle body
- Attaching the load directly to the body structure (direct attachment)

Direct attachment is a common method used to restrain large objects such as vehicles and plant. The load capacity of direct attachment lashings can be impacted by the manner they are used to attach the load onto the vehicle. The angle of the lashing determines the tension that develops in the lashing to restrain a load. The lashing load capacity decreases as the angle increases. This angle is referred to as the Angle Effect (AE).

Failing to consider the impact of Angle Effect when restraining loads, can result in the load to be insufficiently restrained which may result in a contravention.

**Problem Scenario**

To illustrate the impact of Angle Effect, we will use an example of a load weighing 10 tonnes directly attached on a heavy vehicle using 4 X 13mm transport chains with claw hooks, away from any edge contact. The transport chains are rated to a load capacity rating of 9 tonnes each. It is worth noting if the transport chains were affixed with ‘grab hooks’ or made contact with an edge, their load rating capacity would reduce to 6.7 tonne.[8]

##### Determining the Restraint Required

Referring to the performance standard we will need to ensure the load complies with the following:

- 0.8g deceleration in a forward direction
- 0.5g deceleration in a rearward direction
- 0.5g acceleration in sideways direction

To calculate the amount of restraint required we will multiply the weight of the load by the performance standards required:

- 10 tonne X 0.8g = 8 tonne in a forward direction
- 10 tonne X 0.5g = 5 tonne in rearward and sideways direction

**Calculating the Angle Effect**

The Angle Effect applies to every lashing that is used to restrain the load and must be calculated for all directions, forwards, rearwards and sideways. The formula for calculating Angle Effect is as follows[9]:

__Lashing 1__

Angle Effect (AE1) Forwards = Distance (F1) ÷ Length of Lashing (L1)

Angle Effect (AE1) Sideways = Distance (S1) ÷ Length of Lashing (L1)

__Lashing 2__

Angle Effect (AE2) Rearwards = Distance (R2) ÷ Length of Lashing (L2)

Angle Effect (AE2) Sideways = Distance (S2) ÷ Length of Lashing (L2)

We will assume the load has been placed and attached onto the vehicle and we have measured the values required for the above formula as follows:

**Applying the Formula**

**Lashing 1**

To determine the Angle Effect in the **forwards** direction, we will divide the forwards distance of the lashing (F1) by the lashing length:

Angle Effect (Forwards) – F1 (Distance) ÷ L1 (Lashing Length)

Using the numbers in our above example this will be calculated as follows:

Angle Effect (Forwards) – 300 ÷ 1100 = 0.27 AE1

To determine the Angle Effect in the **sideways** direction, we will divide the sideways distance of the load (S1) by the lashing length:

Angle Effect (Sideways) – S1 (Distance) ÷ L1 (Lashing Length)

Using the numbers in our above example this will be calculated as follows:

Angle Effect (Sideways) – 90 ÷ 1100 = 0.08 AE2

Referring to the performance standard, we require 8 tonne of restraint in the forwards direction and 5 tonne of restraint in the sideways direction for our load. To factor in the impact of the Angle Effect on the lashing capacity we will divide the amount of restraint needed in forwards and sideways direction by the respective Angle Effect, this will be calculated as follows:

**Forwards**

Effect of Angle Effect in forwards direction: 8 tonne ÷ 0.27 = 29.63 tonne

As there are 2 chains used to restrain the load in the forwards direction, we will divide this figure by 2 as follows:

29.63 ÷ 2 = 14.85 tonne per chain

The load exceeds the capacity of each chain which is rated for a maximum of 9 tonne. The load would not comply with the load performance standards in the forwards direction.

**Sideways**

Similarly the effect of the Angle Effect in the sideways direction will be calculated as follows:

Affect of Angle Effect in sideways direction: 5 tonne ÷ 0.08 = 62.5 tonne

As there are 2 chains used to restrain the load in the sideways direction, we will divide this figure by 2 as follows:

62.50 ÷ 2 = 31.25 tonne per chain

The load exceeds the capacity of each chain which is rated for a maximum of 9 tonne. The load would not comply with the load performance standards in the sideways direction.

**Lashing 2**

For lashing 2, to determine the Angle Effect in the **rearwards** direction, we will divide the rearwards distance of the lashing (R2) by the lashing length:

Angle Effect (Rearwards) – R2 (Distance) ÷ L2 (Lashing Length)

Using the numbers in our above example this will be calculated as follows:

Angle Effect (Rearwards) – 400 ÷ 1200 = 0.33 AE2

To determine the Angle Effect in the **sideways** direction, we will divide the sideways distance of the load (S2) by the lashing length:

Angle Effect (Sideways) – S2 (Distance) ÷ L2 (Lashing Length)

Using the numbers in our above example this will be calculated as follows:

Angle Effect (Sideways) – 150 ÷ 1200 = 0.125 AE2

Referring back to the performance standard, we require 5 tonne of restraint in the **rearwards **direction and 5 tonne of restraint in the **sideways** direction for our load. To factor in the effect of the Angle Effect on the lashing capacity we will divide the amount of restraint needed in the rearwards and sideways direction by the respective Angle Effect, this will be calculated as follows:

**Rearwards**

Effect of Angle Effect in rearwards direction: 5 tonne ÷ 0.33 = 15.15 tonne

As there are 2 chains used to restrain the load in the rearwards direction, we will divide this figure by 2 as follows:

15.15 ÷ 2 = 7.6 tonne per chain

The load is within the maximum load capacity of each chain, which is 9 tonnes. The load would comply with the load performance standards in the rearwards direction.

**Sideways**

Affect of Angle Effect in sideways direction: 5 tonne ÷ 0.125 = 40.0 tonne

As there are 2 chains used to restrain the load in the sideways direction, we will divide this figure by 2 as follows:

40 ÷ 2 = 20 tonne per chain

The load exceeds the capacity of each chain which is rated for a maximum of 9 tonne. The load would not comply with the load performance standards in the sideways direction.

**How Could This Load be Made Compliant?**

**Increasing the Distance**

The load could be made compliant by increasing the distance between the load and attachment to reduce the Angle Effect. If we increase the F1 distance from 300mm to 900mm and increase the S1 distance from 90mm to 600mm and S2 distance from 150mm to 500mm our calculations are as follows:

**Forwards**

Angle Effect (Forwards) – 900 ÷ 1100 = 0.82 AE1

Effect of Angle Effect in forwards direction: 8 tonne ÷ 0.82 = 9.76 tonne

9.76 ÷ 2 = 4.88 tonne per chain

**Sideways (S1)**

Angle Effect (sideways) – 600 ÷ 1100 = 0.55 AE1

Effect of Angle Effect in sideways direction: 5 tonne ÷ 0.55 = 9.09 tonne

9.09 ÷ 2 = 4.55 tonne per chain

**Sideways (S2)**

Angle Effect (sideways) – 500 ÷ 1200 = 0.42 AE2

Effect of Angle Effect in sideways direction: 5 tonne ÷ 0.42 = 11.90 tonne

11.90 ÷ 2 = 5.95 tonne per chain

The load is now within the load capacity of each chain of 9 tonnes and will comply with the load performance standards in the forwards and sideways direction. We could even replace the chains with lower load capacity chains if required, such as with chains rated for 6 tonne capacity.

**Reducing the Length of the Lashing**

Reducing the length of the lashing could also make the load compliant in the original scenario by reducing the Angle Effect. If we reduce the L1 lashing length of 1100mm to 300mm and L2 lashing length from 1200mm to 400mm, our calculations are as follows:

**Forwards**

Angle Effect (Forwards) – 300 ÷ 300 = 1.0 AE1

Effect of Angle Effect in forwards direction: 8 tonne ÷ 1 = 8.0 tonne

8.0 ÷ 2 = 4.00 tonne per chain

**Sideways (S1)**

Angle Effect (sideways) – 90 ÷ 300 = 0.30 AE1

Effect of Angle Effect in sideways direction: 5 tonne ÷ 0.30 = 16.67 tonne

16.67 ÷ 2 = 8.33 tonne per chain

**Sideways (S2)**

Angle Effect (sideways) – 150 ÷ 400 = 0.38 AE1

Effect of Angle Effect in sideways direction: 5 tonne ÷ 0.38 = 13.16 tonne

13.16 ÷ 2 = 6.58 tonne per chain

The load is now within the load capacity of each chain of 9 tonnes and will comply with the load performance standards in the forwards and sideways direction.

Reducing the lashing length may not be practical and is simply provided here to highlight the impact of lashing length on Angle Effect. It is important to note that the Load Restraint Guide recommends all lashings should be of the same length.[10]

**Using Higher Load Capacity Chains or Reducing the Weight **

The final method would be to reduce the weight of the load or use higher load capacity chains. However, in many circumstances the weight of the load cannot be reduced, such as when transporting plant or vehicles. There are also limits as to the load capacity of chains and higher capacity chains with a load rating capacity of up to 32 tonnes each may not be available.

**Conclusion**

The impact of Angle Effect on direct attachment restraint is significant and can contribute to contraventions under the Heavy Vehicle National Law. The Angle Effect is determined by the length of the lashing and the distance between the load and attachment point. The positioning of the load and attachment onto the vehicle is critical to reducing the impact of the Angle Effect.

Duty holders should ensure they have systems in place to ensure the impact of Angle Effect is calculated and considered when restraining loads to comply with the Heavy Vehicle National Law.

**Risk Controls**

Duty holders should implement effective risk controls to manage the risks arising from insecure loads, which may include:

- Determining and communicating load restraint requirements to relevant persons
- Implementing systems to measure and calculate load restraint requirements
- Marking on vehicles the locations of load placement and attachment to ensure correct restraint
- Utilising load restraint equipment of the highest standard and appropriate load capacity rating
- Implementing procedures to ensure vehicles comply with loading requirements
- Conducting inspections to check condition of load restraint equipment and verify compliance with loading requirements
- Scheduling regular maintenance to ensure vehicles and load restraint equipment is functioning and maintained
- Implementing systems to ensure faulty equipment and vehicles are isolated from use
- Conducting regular training on the risks of insecure loads and loading requirements
- Conducting regular auditing of load management systems to identify any deficiencies and ensure continuous improvement

[1] *Heavy Vehicle National Law 2013* (Vic) section 6.

[2] ibid section 26A.

[3] ibid sections 112-114.

[4] *Heavy Vehicle (Mass, Dimension and Loading) Regulation* 2013 (Vic) schedule 7, section 1.

[5] ibid schedule 7, section 2.

[6] ibid schedule 7, section 2.

[7] ibid schedule 7, section 2.

[8] Load Restraint Guide 2018, pg 27, National Transport Commission.

[9] ibid pg 252.

[10] ibid pg 28.