Innovative Transport Solutions Pty Ltd have developed an affordable product that transforms commercial vehicle, into a fully functioning hybrid vehicle, Hydraulic Drive Assist hybrid system.

To help the reader understand the associated prefixes used to describe motor vehicle driveline and axle configurations, we have produced these following images and explanations. This information may seem to some to be stating the obvious, but not all readers have a background in the transport industry. 

Most people will be familiar with the 4X4 logo found on motor vehicles.  

The first digit "4" refers to the number of wheels visible the outside of  the motor vehicle. If dual wheels are fitted to the same axle, the inside wheel is not counted.

The second digit "4" refers to the number of driving wheels. Hence a 4X4 can be driven in all wheel drive (AWD) in some models the front axle can be disengaged manually to conserve fuel.

Car Axle Configurations


Figure A. Four outside wheels and four driving wheels, 4 X 4.

Figure B. Four outside wheels and two driving wheels, 4 X 2.

Figure C. Four outside wheels And four driving wheels, 4 X 4 (inside wheels are not counted)

Figure D. Four outside wheels and two driving, 4 X 2 (inside wheels are not counted)

Figure E. Heavy vehicle ( army truck) eight outside wheels and eight wheels driving, 8 X 8, (inside wheels are not counted)



Any number of axles and drive combinations are possible, in the vehicle numbering system there is no distinction between steer and non steer wheels. The images below are of typical axle configurations for trucks and busses.  

Truck Axle Configurations

Additional axles are installed strategically to increase the vehicles pay load. Note that only the axles that attach to the vehicle drive shaft are driven axles. Two axles close together at the front of the vehicle are also referred to as twin steer vehicles, in some cases steer axles are also driven, as in the 8X8 image above. (figure E)



Bus & Coach Axle Configurations

Buses and coaches have the most variety of axle and driveline configurations, below is a sample of the most common bus chassis designs.


1 Front Engine Bus, 4X2 

2 Rear Engine Bus, 8X2 

3 Rear Engine Bus, 4X2

4 Rear Engine Bus, 6X2

5 Under Floor Mid Engine Bus, 4X2

6 Rear Engine Bus, 6X2

7 Transverse Rear Engine, 4X2

8 Articulated rear engine Bus, 6X2

9 Side Mounted Mid Engine Bus, 4X2

10 Articulated Mid Engine bus, 6X2

11 Side Mounted Rear Engine Bus, 4X2

12 Articulated Transverse Rear Engine Bus, 6X2

Hybrid Vehicle Driveline 

Rear wheel drive layouts pictured below depict six different positions of a hybrid drive module that can be used to produce a hybrid drive vehicle. Image 2 and 4 are the main designs we use to produce our electric and hydraulic hybrid drive systems.

We are currently developing a Front Wheel Drive (FWD) hydraulic hybrid system for motor cars and light commercial vehicles. Our targeted market will be FWD delivery vans of all sizes.



Australian chart below may help in understanding axle configuration classifications, the size weight and number of axles are used to calculate the registration and tax to be paid on a particular vehicle.