South Australia
Road Traffic (Mass and Loading Requirements) Regulations 1999
under the Road Traffic Act 1961

Contents
1	Short title
3	Schedule contains mass and loading requirements
4	Interpretation
5	Application of the mass and loading requirements
6	Proof of loading offences
7	Declaring buses to be complying buses
Schedule 1—Mass and loading requirements for heavy vehicles
Part 1—Mass limits
1	Mass limit for a single vehicle
2	Mass limits for tyres, wheels and axles
3	Mass limits relating to axle spacing
4	Mass limits for combinations
Part 2—Size and projection of loads
5	Size limits
6	Front and side projections
7	Rear projections
8	Dangerous projections
Part 3—Placing and securing loads
9	Loading obligations
10	Trailers
Schedule 2—Mass and loading requirements for light vehicles
1	Mass limit for a single light vehicle
2	Mass of vehicle towed by light vehicle
3	Application of Parts 2 and 3 of Schedule 1
Dictionary
Legislative history

1—Short title
These regulations may be cited as the Road Traffic (Mass and Loading Requirements) Regulations 1999.
3—Schedule contains mass and loading requirements
The Schedules contain mass and loading requirements made pursuant to section 113 of the Road Traffic Act 1961.
Notes—
1	Section 114 of the Road Traffic Act 1961 provides that the driver and the owner and the operator of a vehicle driven or towed on a road are each guilty of an offence if the vehicle or a load on the vehicle does not comply with the mass and loading requirements. For that purpose, vehicle includes a combination.
2	Under section 161A of the Road Traffic Act 1961, certain vehicles can only be driven on roads with the approval of the Minister.
4—Interpretation
	(1)	A definition in the dictionary at the end of these regulations applies to each use of the word or expression in these regulations, unless the contrary intention appears.
	(2)	A note does not form part of these regulations.
	(3)	A diagram appearing in these regulations is illustrative only.
5—Application of the mass and loading requirements
	(1)	Except as provided in Schedule 2, Schedule 1 applies only to the following (heavy vehicles):
	(a)	vehicles with a GVM exceeding 4.5 tonnes;
	(b)	combinations that include a vehicle with a GVM exceeding 4.5 tonnes.
	(2)	Schedule 2 applies to other vehicles (light vehicles).
	(3)	Neither Schedule 1 nor Schedule 2 applies to a vehicle or combination that is used only on a railway or tramway.
6—Proof of loading offences
	(1)	In proceedings for a failure to comply with clause 9 (1), (2) or (3) of Schedule 1 (relating to loading a vehicle), it is sufficient for the prosecution to prove that the load on the vehicle was not placed, secured or restrained (as the case requires) in a way that met the performance standards recommended in the Load Restraint Guide as amended from time to time and published by the Australian Government Publishing Service.
	(2)	If the prosecution in proceedings for a failure to comply with clause 9 (2) of Schedule 1 (relating to securing a load on a vehicle) proves that the load, or part of the load, had fallen off the vehicle, the burden of proof is on the defendant to show compliance.
7—Declaring buses to be complying buses
	(1)	This regulation applies to a bus with two or three axles and a single steer axle that:
	(a)	is not fitted with a compliance plate in accordance with the Motor Vehicle Standards Act 1989 of the Commonwealth, as in force from time to time; or
	(b)	is fitted with a compliance plate in accordance with that Act but the compliance plate indicates that the bus was manufactured before 1 July 1994.
	(2)	The Registrar of Motor Vehicles may declare that a bus equipped with an approved air suspension system is a complying bus for the purposes of these regulations if the Registrar is satisfied that the bus meets:
	(a)	the emergency exit specifications in ADR 44; and
	(b)	the rollover strength specifications in ADR 59; and
	(c)	the occupant protection specifications in ADR 68.

Schedule 1—Mass and loading requirements for heavy vehicles
Part 1—Mass limits
1—Mass limit for a single vehicle
	(1)	The total mass of a vehicle and any load must not exceed the vehicle's GVM.
	(2)	The mass transmitted to the ground by the axles of a trailer and any load when the trailer is connected to a towing vehicle must not exceed the trailer's GTM.
2—Mass limits for tyres, wheels and axles
	(1)	The mass on a wheel or axle must not exceed the limit set by its manufacturer.
	(2)	The mass on a tyre must not exceed the greatest load capacity determined for the tyre by the manufacturer at a cold inflation pressure that does not exceed:
	(a)	825 kilopascals for a radial ply tyre; or
	(b)	700 kilopascals for any other tyre.
	(3)	The mass on an axle group or single axle must not exceed the limit provided for it in Table 1.
	(4)	The mass limit in Table 1 that applies to an axle group that includes a retractable axle must be determined as if the axle did not exist, unless subclause (5) applies.
	(5)	A retractable axle is part of an axle group for the purposes of Table 1 if, when the mass on the group exceeds:
	(a)	6 tonnes, in the case of a tandem axle group; or
	(b)	11 tonnes, in the case of a tri‑axle group,
the tyres on the axle are in contact with the ground and the load‑sharing suspension system is operating on each axle (including the retractable axle) and tyre in the group.
	(6)	The sum of the mass on the axle groups and single axles on a vehicle or combination must not exceed:
	(a)	in the case of a complying bus without a trailer:
	(i)	if the complying bus has 2 axles—16.0 tonnes; and
	(ii)	if the complying bus has a rear tandem axle group fitted with single tyres on one axle and dual tyres on the other axle—20.0 tonnes; and
	(iii)	if the complying bus has a rear tandem axle group fitted with dual tyres on both axles—22.5 tonnes; and
	(b)	in the case of a combination consisting of a complying bus and a trailer—the sum of the mass limit specified for the bus in paragraph (a) and the mass limits of the axle groups and single axles of the trailer as provided in Table 1; and
	(ba)	in the case of a low floor bus with 2 axles that is licensed to carry standing passengers—16.0 tonnes; and
	(c)	in any other case—the sum of the mass limits of the axle groups and axles, as provided in Table 1.
	(7)	In this clause and in Table 1—
low floor bus means a bus, designed to assist the entry, exit and movement of passengers—
	(a)	that has no internal step at an entrance or exit or otherwise in the passenger walkway areas of the bus; or
	(b)	that, due to the area of the floor of the bus that is not more than 550 mm above the ground, is not required to comply with ADR 59.

Table 1—Mass limits for single axles and axle groups
Description of single axle or axle group	Mass Limit
(tonnes)	
Single axles and single axle groups		
Single steer axle on:		
	(a)	a complying bus	6.5	
	(b)	any other motor vehicle	6.0	
Single axle or single axle group fitted with single tyres with section width of:		
	(a)	less than 375 mm	6.0	
	(b)	at least 375 mm but less than 450 mm	6.7	
	(c)	at least 450 mm	7.0	
Single axle or single axle group fitted with dual tyres on:		
	(a)	a pig trailer	8.5	
	(b)	a complying bus or bus licensed to carry standing passengers (other than a bus referred to in paragraph (ba))	10.0	
	(ba)	a low floor bus with 2 axles that is licensed to carry standing passengers	11.0	
	(c)	any other vehicle	9.0	
Twinsteer axle groups		
Twinsteer axle group without a load‑sharing suspension system	10.0	
Twinsteer axle group with a load‑sharing suspension system	11.0	
Tandem axle groups		
Tandem axle group fitted with single tyres with section width of:		
	(a)	less than 375 mm	11.0	
	(b)	at least 375 mm but less than 450 mm	13.3	
	(c)	at least 450 mm	14.0	
Tandem axle group fitted with single tyres on one axle and dual tyres on the other axle on:		
	(a)	a complying bus	14.0	
	(b)	any other vehicle	13.0	
Tandem axle group fitted with dual tyres on:		
	(a)	a pig trailer	15.0	
	(b)	any other vehicle	16.5	
Tri‑axle groups		
Tri‑axle group on a vehicle fitted with single tyres with section width of less than 375 mm on all axles, or single tyres on 1 or 2 axles and dual tyres on the other axle or axles	15.0	
Tri‑axle group on a pig trailer with either single tyres with section width of at least 375 mm, dual tyres on all axles, or a combination of those tyres	18.0	
Tri‑axle group, on a vehicle other than a pig trailer, with either single tyres with section width of at least 375 mm, dual tyres, or a combination of those tyres	20.0	
Quad‑axle groups		
Quad‑axle group fitted with single tyres with section width of less than 375 mm	15.0	
Quad‑axle group fitted with single tyres with section width of at least 375 mm or dual tyres	20.0	
3—Mass limits relating to axle spacing
	(1)	If the total mass of a vehicle or a combination, and any load, cannot lawfully exceed 42.5 tonnes, the mass limits in Table 2 must not be exceeded in relation to the distances set out in the Table that apply to the vehicle or combination.
	(2)	In the case of a road train, the mass limits in Table 3 must not be exceeded in relation to the distances set out in the Table that apply to the road train.
	(3)	In the case of a B‑double, the mass limits in Table 4 must not be exceeded in relation to the distances set out in the Table that apply to the B‑double.
	(4)	Each distance in Table 2, 3 or 4 refers to:
	(a)	the distance from the centre of any single axle to the centre of any other single axle; or
	(b)	the distance from the centre of any single axle to the centre of the furthest axle in any axle group; or
	(c)	the greatest distance between the centres of axles in any 2 axle groups.

Measurement of distances for Tables 2, 3 and 4
	(5)	The mass limits in Table 2, 3 or 4 apply to the sum of the mass on each axle group or single axle in the distance referred to in the Table, including the axles between which the distance is measured.
	(6)	The total mass of a vehicle or a combination, and any load, must not exceed 15 tonnes if the distance between any 2 axles that are not part of the same axle group is less than 2.5 metres.

Table 2—Mass limits relating to axle spacing (other than road trains and b-doubles)
Distance (metres)		Mass limit	Distance (metres)		Mass limit	
exceeding	not exceeding	(tonnes)	exceeding	not exceeding	(tonnes)	
0	3.7	23.0	6.8	7.0	33.0	
3.7	3.8	23.5	7.0	7.2	33.5	
3.8	4.0	24.0	7.2	7.3	34.0	
4.0	4.2	24.5	7.3	7.5	34.5	
4.2	4.3	25.0	7.5	7.7	35.0	
4.3	4.5	25.5	7.7	7.8	35.5	
4.5	4.7	26.0	7.8	8.0	36.0	
4.7	4.8	26.5	8.0	8.2	36.5	
4.8	5.0	27.0	8.2	8.3	37.0	
5.0	5.2	27.5	8.3	8.5	37.5	
5.2	5.3	28.0	8.5	8.7	38.0	
5.3	5.5	28.5	8.7	8.8	38.5	
5.5	5.7	29.0	8.8	9.0	39.0	
5.7	5.8	29.5	9.0	9.2	39.5	
5.8	6.0	30.0	9.2	9.3	40.0	
6.0	6.2	30.5	9.3	9.5	40.5	
6.2	6.3	31.0	9.5	9.7	41.0	
6.3	6.5	31.5	9.7	9.8	41.5	
6.5	6.7	32.0	9.8	10.0	42.0	
6.7	6.8	32.5	10.0		42.5	

Table 3—Mass limits relating to axle spacing (road trains)
Distance (metres)		Mass limit	Distance (metres)		Mass limit	
exceeding	not exceeding	(tonnes)	exceeding	not exceeding	(tonnes)	
3.5	3.7	23.0	10.2	10.3	43.0	
3.7	3.8	23.5	10.3	10.5	43.5	
3.8	4.0	24.0	10.5	10.7	44.0	
4.0	4.2	24.5	10.7	10.8	44.5	
4.2	4.3	25.0	10.8	11.0	45.0	
4.3	4.5	25.5	11.0	11.2	45.5	
4.5	4.7	26.0	11.2	11.3	46.0	
4.7	4.8	26.5	11.3	11.5	46.5	
4.8	5.0	27.0	11.5	11.7	47.0	
5.0	5.2	27.5	11.7	11.8	47.5	
5.2	5.3	28.0	11.8	12.0	48.0	
5.3	5.5	28.5	12.0	12.2	48.5	
5.5	5.7	29.0	12.2	12.3	49.0	
5.7	5.8	29.5	12.3	12.5	49.5	
5.8	6.0	30.0	12.5	12.7	50.0	
6.0	6.2	30.5	12.7	12.8	50.5	
6.2	6.3	31.0	12.8	13.0	51.0	
6.3	6.5	31.5	13.0	13.2	51.5	
6.5	6.7	32.0	13.2	13.3	52.0	
6.7	6.8	32.5	13.3	13.5	52.5	
6.8	7.0	33.0	13.5	13.7	53.0	
7.0	7.2	33.5	13.7	13.8	53.5	
7.2	7.3	34.0	13.8	14.0	54.0	
7.3	7.5	34.5	14.0	14.2	54.5	
7.5	7.7	35.0	14.2	14.3	55.0	
7.7	7.8	35.5	14.3	14.5	55.5	
7.8	8.0	36.0	14.5	14.7	56.0	
8.0	8.2	36.5	14.7	14.8	56.5	
8.2	8.3	37.0	14.8	15.0	57.0	
8.3	8.5	37.5	15.0	15.2	57.5	
8.5	8.7	38.0	15.2	15.3	58.0	
8.7	8.8	38.5	15.3	15.5	58.5	
8.8	9.0	39.0	15.5	15.7	59.0	
9.0	9.2	39.5	15.7	15.8	59.5	
9.2	9.3	40.0	15.8	16.0	60.0	
9.3	9.5	40.5	16.0	16.2	60.5	
9.5	9.7	41.0	16.2	16.3	61.0	
9.7	9.8	41.5	16.3	16.5	61.5	
9.8	10.0	42.0	16.5	16.7	62.0	
10.0	10.2	42.5	16.7	16.8	62.5	
16.8	17.0	63.0	23.5	23.7	83.0	
17.0	17.2	63.5	23.7	23.8	83.5	
17.2	17.3	64.0	23.8	24.0	84.0	
17.3	17.5	64.5	24.0	24.2	84.5	
17.5	17.7	65.0	24.2	24.3	85.0	
17.7	17.8	65.5	24.3	24.5	85.5	
17.8	18.0	66.0	24.5	24.7	86.0	
18.0	18.2	66.5	24.7	24.8	86.5	
18.2	18.3	67.0	24.8	25.0	87.0	
18.3	18.5	67.5	25.0	25.2	87.5	
18.5	18.7	68.0	25.2	25.3	88.0	
18.7	18.8	68.5	25.3	25.5	88.5	
18.8	19.0	69.0	25.5	25.7	89.0	
19.0	19.2	69.5	25.7	25.8	89.5	
19.2	19.3	70.0	25.8	26.0	90.0	
19.3	19.5	70.5	26.0	26.2	90.5	
19.5	19.7	71.0	26.2	26.3	91.0	
19.7	19.8	71.5	26.3	26.5	91.5	
19.8	20.0	72.0	26.5	26.7	92.0	
20.0	20.2	72.5	26.7	26.8	92.5	
20.2	20.3	73.0	26.8	27.0	93.0	
20.3	20.5	73.5	27.0	27.2	93.5	
20.5	20.7	74.0	27.2	27.3	94.0	
20.7	20.8	74.5	27.3	27.5	94.5	
20.8	21.0	75.0	27.5	27.7	95.0	
21.0	21.2	75.5	27.7	27.8	95.5	
21.2	21.3	76.0	27.8	28.0	96.0	
21.3	21.5	76.5	28.0	28.2	96.5	
21.5	21.7	77.0	28.2	28.3	97.0	
21.7	21.8	77.5	28.3	28.5	97.5	
21.8	22.0	78.0	28.5	28.7	98.0	
22.0	22.2	78.5	28.7	28.8	98.5	
22.2	22.3	79.0	28.8	29.0	99.0	
22.3	22.5	79.5	29.0	29.2	99.5	
22.5	22.7	80.0	29.2	29.3	100.0	
22.7	22.8	80.5	29.3	29.5	100.5	
22.8	23.0	81.0	29.5	29.7	101.0	
23.0	23.2	81.5	29.7	29.8	101.5	
23.2	23.3	82.0	29.8	30.0	102.0	
23.3	23.5	82.5	30.0	30.2	102.5	
30.2	30.3	103.0	32.3	32.5	109.5	
30.3	30.5	103.5	32.5	32.7	110.0	
30.5	30.7	104.0	32.7	32.8	110.5	
30.7	30.8	104.5	32.8	33.0	111.0	
30.8	31.0	105.0	33.0	33.2	111.5	
31.0	31.2	105.5	33.2	33.3	112.0	
31.2	31.3	106.0	33.3	33.5	112.5	
31.3	31.5	106.5	33.5	33.7	113.0	
31.5	31.7	107.0	33.7	33.8	113.5	
31.7	31.8	107.5	33.8	34.0	114.0	
31.8	32.0	108.0	34.0	34.2	114.5	
32.0	32.2	108.5	34.2	34.3	115.0	
32.2	32.3	109.0	34.3	34.5	115.5	

Table 4—Mass limits relating to axle spacing (b-doubles)
Distance (metres)		Mass limit	Distance (metres)		Mass limit	
exceeding	not exceeding	(tonnes)	exceeding	not exceeding	(tonnes)	
0	3.7	23.0	7.2	7.3	34.0	
3.7	3.8	23.5	7.3	7.5	34.5	
3.8	4.0	24.0	7.5	7.7	35.0	
4.0	4.2	24.5	7.7	7.8	35.5	
4.2	4.3	25.0	7.8	8.0	36.0	
4.3	4.5	25.5	8.0	8.2	36.5	
4.5	4.7	26.0	8.2	8.3	37.0	
4.7	4.8	26.5	8.3	8.5	37.5	
4.8	5.0	27.0	8.5	8.7	38.0	
5.0	5.2	27.5	8.7	8.8	38.5	
5.2	5.3	28.0	8.8	9.0	39.0	
5.3	5.5	28.5	9.0	9.2	39.5	
5.5	5.7	29.0	9.2	9.3	40.0	
5.7	5.8	29.5	9.3	9.5	40.5	
5.8	6.0	30.0	9.5	9.7	41.0	
6.0	6.2	30.5	9.7	9.8	41.5	
6.2	6.3	31.0	9.8	10.0	42.0	
6.3	6.5	31.5	10.0	10.2	42.5	
6.5	6.7	32.0	10.2	10.3	43.0	
6.7	6.8	32.5	10.3	10.5	43.5	
6.8	7.0	33.0	10.5	10.7	44.0	
7.0	7.2	33.5	10.7	10.8	44.5	
10.8	11.0	45.0	16.0	16.3	53.5	
11.0	11.2	45.5	16.3	16.7	54.0	
11.2	11.3	46.0	16.7	17.0	54.5	
11.3	11.7	46.5	17.0	17.3	55.0	
11.7	12.0	47.0	17.3	17.7	55.5	
12.0	12.3	47.5	17.7	18.0	56.0	
12.3	12.7	48.0	18.0	18.3	56.5	
12.7	13.0	48.5	18.3	18.7	57.0	
13.0	13.3	49.0	18.7	19.0	57.5	
13.3	13.7	49.5	19.0	19.3	58.0	
13.7	14.0	50.0	19.3	19.7	58.5	
14.0	14.3	50.5	19.7	20.0	59.0	
14.3	14.7	51.0	20.0	20.3	59.5	
14.7	15.0	51.5	20.3	20.7	60.0	
15.0	15.3	52.0	20.7	21.0	60.5	
15.3	15.7	52.5	21.0		62.5	
15.7	16.0	53.0				
4—Mass limits for combinations
	(1)	The total mass of a combination other than a road train or B-double, and any load, must not exceed 42.5 tonnes.
	(2)	The loaded mass of a dog trailer or pig trailer must not exceed the loaded mass of the towing vehicle.
	(3)	The total mass of a combination, and any load, must not exceed the towing vehicle's GCM.
	(4)	If:
	(a)	the manufacturer of a motor vehicle forming part of a road train or B‑double has not determined the GCM of the vehicle; or
	(b)	the manufacturer cannot be identified; or
	(c)	the vehicle has been modified to the extent that the manufacturer's specification is no longer appropriate,
the GCM of the vehicle is to be determined by the Registrar of Motor Vehicles as a mass not exceeding the mass determined in accordance with the following formula if the Registrar is the vehicle registration authority in relation to the vehicle:

where:
K means:
	(a)	0.055 if a single drive axle is fitted to the motor vehicle; or
	(b)	0.053 if a single drive tandem axle group is fitted to the motor vehicle; or
	(c)	0.051 if a dual drive tandem axle group is fitted to the motor vehicle;
M means the number of tyre revolutions per kilometre as specified by the tyre manufacturer for the tyres fitted to the driving axle or axles;
R means the overall gear reduction between engine and drive wheels;
T means the maximum engine net torque in newton-metres.
	(5)	The total mass of a road train, and any load, must not exceed 115.5 tonnes.
	(6)	The total mass of a B-double, and any load, must not exceed 62.5 tonnes.
Part 2—Size and projection of loads
5—Size limits
	(1)	A vehicle or a combination, and its load, must not exceed a size limit set for the vehicle or combination in the vehicle standards.
	(2)	The distance measured at right angles between the rear overhang line of a vehicle and the rear of any load it is carrying must not exceed the rear overhang that the vehicle is allowed under the vehicle standards.

Illustration of front projection limit, rear overhang limit from vehicle standards and maximum rear projection of load allowed without a warning signal
	(3)	In spite of subclauses (1) and (2):
	(a)	the height of a vehicle that is carrying vehicles on more than one deck, and its load, must not exceed 4.6 metres; and
	(b)	the distance measured at right angles between the rear overhang line of a trailer carrying vehicles on more than one deck and the rear of the rearmost vehicle on the trailer must not exceed 4.9 metres.

Height limit and rear overhang limit of a loaded car carrier
6—Front and side projections
A load on a vehicle must not project more than 1.2 metres in front of the vehicle, or more than 150 millimetres from the outermost part of either side of it.

Vehicle loaded to width limits referred to in clause 5(1), with maximum side projection of load allowed under clause 6
Note—
The combined dimensions of a vehicle and its load must still meet the requirements of clause 5 even if the load projects from the vehicle in any direction.
7—Rear projections
	(1)	The rear of a load on a vehicle must carry a warning signal if the load:
	(a)	projects more than 1.2 metres behind the vehicle; or
	(b)	projects to the rear of the vehicle so that the end of the load cannot be seen easily from behind; or
	(c)	is on a pole-type trailer.
	(2)	In daytime, the warning signal must be a brightly coloured flag or piece of material, with each side at least 300 millimetres long.
	(3)	In the night‑time, the warning signal must be a red light which can be seen for 200 metres.
8—Dangerous projections
A load on a vehicle must not project in a way that is dangerous to a person or to property, even if all dimension and warning requirements are met.
Part 3—Placing and securing loads
9—Loading obligations
	(1)	A load on a vehicle must not be placed in a way that makes the vehicle unstable or unsafe.
	(2)	A load on a vehicle must be secured so that it is unlikely to fall or be dislodged from the vehicle.
	(3)	An appropriate method must be used to restrain the load on a vehicle.
10—Trailers
	(1)	A trailer in a combination must be securely coupled to the vehicle in front of it.
	(2)	The components of a coupling used between vehicles must be compatible and properly connected to each other.

Schedule 2—Mass and loading requirements for light vehicles
1—Mass limit for a single light vehicle
	(1)	The mass of any load on a vehicle must not exceed a maximum specified by the vehicle's manufacturer.
	(2)	The total mass of a vehicle and any load must not exceed a maximum specified by the vehicle's manufacturer.
2—Mass of vehicle towed by light vehicle
The loaded mass of a vehicle towed by another vehicle must not exceed—
	(a)	the capacity of the towing apparatus of the towing vehicle; or
	(b)	a mass specified by the manufacturer of the towing vehicle as the maximum mass of a vehicle that may be towed by the towing vehicle; or
	(c)	if a mass is not specified by the manufacturer of the towing vehicle as referred to in paragraph (b) and the towed vehicle is fitted with brakes that may be operated by the driver of the towing vehicle—one and a half times the unloaded mass of the towing vehicle; or
	(d)	if a mass is not specified by the manufacturer of the towing vehicle as referred to in paragraph (b) and the towed vehicle is not fitted with brakes that may be operated by the driver of the towing vehicle—the unloaded mass of the towing vehicle.
3—Application of Parts 2 and 3 of Schedule 1
Parts 2 and 3 of Schedule 1 also apply to light vehicles.

Dictionary
In these regulations—
ADR (Australian Design Rule) means a national standard under the Motor Vehicle Standards Act 1989 of the Commonwealth, as in force from time to time;
approved air suspension system, in relation to a vehicle, means a suspension system in which:
	(a)	vertical movement between each axle and the body of the vehicle is controlled by variations in the pressure of air in an air spring; and
	(b)	the proportion of the vehicle's mass that is borne by the air spring remains substantially constant despite variations in the pressure of air in the air spring;
axle means one or more shafts positioned in a line across a vehicle, on which one or more wheels intended to support the vehicle turn;
axle group means a single axle group, tandem axle group, twinsteer axle group, tri‑axle group or quad‑axle group;
B-double means a combination consisting of a prime mover towing 2 semi-trailers where the first semi‑trailer is connected to the prime mover by a fifth wheel coupling and the second semi‑trailer is connected to the first semi‑trailer by a fifth wheel coupling;

Typical B-double
centre of an axle group means:
	(a)	a line located midway between the centre-lines of the outermost axles of the group; or
	(b)	if the group consists of 2 axles, one of which is fitted with twice the number of tyres as the other axle—a line located one third of the way from the centre‑line of the axle with more tyres towards the centre‑line of the axle with fewer tyres;

Centre of a typical tandem axle group fitted with an equal number of tyres on each axle

Centre of a typical tandem axle group fitted with a different number of tyres on each axle

Centre of a typical tri-axle group

Centre of a typical quad-axle group
combination means a group of vehicles consisting of a motor vehicle connected to one or more vehicles;
complying bus means:
	(a)	a bus with 2 or 3 axles and a single steer axle that:
	(i)	is fitted with a compliance plate in accordance with the Motor Vehicle Standards Act 1989 of the Commonwealth, as in force from time to time, indicating that the bus was manufactured during or after July 1994; and
	(ii)	meets the emergency exit specifications in ADR 44; and
	(iii)	meets the rollover strength specifications in ADR 59; and
	(iv)	meets the occupant protection specifications in ADR 68; and
	(v)	is equipped with an approved air suspension system; or
	(b)	a bus that is the subject of a declaration under regulation 7 or under a corresponding law of another State or a Territory;
converter dolly means a trailer with one tandem axle group or single axle and a fifth wheel coupling designed to convert a semi‑trailer into a dog trailer;

Typical converter dolly
dog trailer means a trailer (including a trailer consisting of a semi-trailer and converter dolly) with:
	(a)	one axle group or single axle at the front that is steered by connection to the towing vehicle by a drawbar; and
	(b)	one axle group or single axle at the rear;

Typical dog trailer
drawbar means a part of a trailer (other than a semi-trailer) that connects the trailer body to a coupling for towing purposes;
fifth wheel coupling means a device, other than the upper rotating element and the kingpin (which are parts of a semi‑trailer), used with a prime mover, semi‑trailer or a converter dolly to permit quick coupling and uncoupling and to provide for articulation;
GCM (gross combination mass), in relation to a motor vehicle, means the greatest possible sum of the maximum loaded mass of the motor vehicle and of any vehicles that may lawfully be towed by it at one time:
	(a)	as specified by the motor vehicle's manufacturer:
	(i)	on a plate fixed to the vehicle by the manufacturer; or
	(ii)	if the manufacturer has not specified the sum of the maximum loaded mass on a plate fixed to the vehicle—in another place; or
	(b)	as specified by the vehicle registration authority if:
	(i)	the manufacturer has not specified the sum of the maximum loaded mass; or
	(ii)	the manufacturer cannot be identified; or
	(iii)	the vehicle has been modified to the extent that the manufacturer's specification is no longer appropriate;
GTM (gross trailer mass) means the maximum loaded mass transmitted to the ground by the axles of a trailer when it is connected to a towing vehicle:
	(a)	as specified by the manufacturer; or
	(b)	as specified by the vehicle registration authority if:
	(i)	the manufacturer has not specified a maximum loaded mass transmitted to the ground by the axles of the trailer when connected to a towing vehicle; or
	(ii)	the manufacturer cannot be identified; or
	(iii)	the trailer has been modified to the extent that the manufacturer's specification is no longer appropriate;
GVM (gross vehicle mass) means the maximum loaded mass of a vehicle:
	(a)	as specified by the manufacturer; or
	(b)	as specified by the vehicle registration authority if:
	(i)	the manufacturer has not specified a maximum loaded mass; or
	(ii)	the manufacturer cannot be identified; or
	(iii)	the vehicle has been modified to the extent that the manufacturer's specification is no longer appropriate;
load, in relation to a vehicle, includes anything that is normally removed from the vehicle when the vehicle is not in use;
load-sharing suspension system means an axle group suspension system that:
	(a)	is built to divide the load between the tyres on the group so that no tyre carries a mass more than 10% greater than the mass it would carry if the load were divided equally; and
	(b)	has effective damping characteristics on all axles of the group;
night-time means the time beginning at sunset and ending at sunrise;
pig trailer means a trailer with one axle group or single axle near the middle of its load‑carrying surface, and connected to the towing vehicle by a drawbar;

Typical pig trailer
pole-type trailer means a trailer that:
	(a)	is attached to a towing vehicle by means of a pole or an attachment fitted to a pole; and
	(b)	is ordinarily used for transporting loads, such as logs, pipes, structural members or other long objects, that are generally capable of supporting themselves like beams between supports;

Typical pole-type trailer
prime mover means a motor vehicle built to tow a semi-trailer;
quad-axle group means a group of 4 axles, in which the horizontal distance between the centre‑lines of the outermost axles is more than 3.2 metres but not more than 4.9 metres;
rear overhang line means:
	(a)	if there is a single axle at the rear of the vehicle—the centre‑line of the axle; or
	(b)	if there is an axle group at the rear of the vehicle—the centre of the axle group, determined without regard to the presence of any steerable axle or retractable axle in the group unless all axles in the group are steerable or retractable;

Rear overhang line on a typical motor vehicle that has an axle group

Rear overhang line on a typical semi-trailer
retractable axle means an axle that can be raised so that the tyres on the axle do not touch the ground;
road train means a combination, other than a B-double, consisting of a motor vehicle towing at least 2 trailers (counting as one trailer a converter dolly supporting a semi‑trailer);

Typical triple road train
semi-trailer means a trailer that has:
	(a)	one axle group or single axle towards the rear; and
	(b)	a means of attachment to a prime mover that would result in some of the load being imposed on the prime mover;
single axle means an axle not forming part of an axle group;
single axle group means a group of 2 or more axles, in which the horizontal distance between the centre‑lines of the outermost axles is less than 1 metre;
tandem axle group means a group of at least 2 axles, in which the horizontal distance between the centre‑lines of the outermost axles is at least 1 metre, but not more than 2 metres;
tri-axle group means a group of at least 3 axles, in which the horizontal distance between the centre‑lines of the outermost axles is more than 2 metres, but not more than 3.2 metres;
twinsteer axle group means a group of 2 axles:
	(a)	with single tyres; and
	(b)	fitted to a motor vehicle; and
	(c)	connected to the same steering mechanism; and
	(d)	the horizontal distance between whose centre-lines is at least 1 metre, but not more than 2 metres;

Typical twinsteer axle group on a motor vehicle
vehicle includes the vehicle's equipment and any substances that the vehicle is carrying that are essential for its operation;
vehicle registration authority, in relation to a vehicle, means:
	(a)	the authority that last registered the vehicle; or
	(b)	if the vehicle has never been registered—the authority responsible for registering vehicles in the State or Territory in which the vehicle is used or is intended to be used;
vehicle standards means the Road Traffic (Vehicle Standards) Rules 1999.

Legislative history
Notes
	•	Variations of this version that are uncommenced are not incorporated into the text.
	•	Please note—References in the legislation to other legislation or instruments or to titles of bodies or offices are not automatically updated as part of the program for the revision and publication of legislation and therefore may be obsolete.
	•	Earlier versions of these regulations (historical versions) are listed at the end of the legislative history.
	•	For further information relating to the Act and subordinate legislation made under the Act see the Index of South Australian Statutes or www.legislation.sa.gov.au.
Principal regulations and variations
New entries appear in bold.
Year	No	Reference	Commencement	
1999	234	Gazette 25.11.1999 p2575	1.12.1999	
2001	122	Gazette 7.6.2001 p2192	7.6.2001	
2005	194	Gazette 8.9.2005 p3278	8.9.2005: r 2 	
2007	44	Gazette 26.4.2007 p1388	30.4.2007: r 2	
Provisions varied
New entries appear in bold.
Provision	How varied	Commencement	
r 2	omitted under the Legislation Revision and Publication Act 2002	8.9.2005	
Sch 1			
cl 1			
cl 1(1)	cl 1 redesignated as cl 1(1) by 122/2001 r 3(a)	7.6.2001	
cl 1(2)	inserted by 122/2001 r 3(a)	7.6.2001	
cl 2			
cl 2(6)	varied by 122/2001 r 3(b)	7.6.2001	
	varied by 194/2005 r 4(1)	8.9.2005	
cl 2(7)	inserted by 122/2001 r 3(c)	7.6.2001	
ultra low floor bus	deleted by 194/2005 r 4(2)	8.9.2005	
low floor bus	inserted by 194/2005 r 4(2)	8.9.2005	
Table 1	varied by 122/2001 r 3(d)	7.6.2001	
	varied by 194/2005 r 4(3)	8.9.2005	
Dictionary			
GTM	inserted by 122/2001 r 4	7.6.2001	
Historical versions
Reprint No 1—7.6.2001