passenger and special purpose vehicles design process

Vehicle design development is an intricate and time consuming process, and this can be even more depending on the type of vehicle to design. Even though there are all vehicles, which apart from being a mean which allow us to move from a point ‘A’ to a point ‘B’ in the most quick and efficient way, vehicles are quiet different depending on the purpose they will be used for. A passenger vehicle may be design to simply allow the customer or user to satisfy daily transportation needs, this is not the case of an off-road vehicle or luxury cars. In such a way their development process differs also. .in this article we enlighten the passenger/commercial trucks and special purpose vehicles design process.

Manufacturing industry or passenger /commercial truck design approach

The car manufacturing industry usually has an aesthetic approach, so they start with aesthetics. Following are the steps.

1-generate the concepts on paper

Concept generation may begin with a benchmarking of the company previous models or a competitor models, the company wants to target new segment or the designer has fresh ideas and goes sketch after sketch to generate a new concept.

2-Choosing a concept

Among the sketches generated one or few which are most marketable, ease of production, reasonable production cost need to be chose for further processing. It’s like a funnel starting with many and filter down to get one.  


The packaging is the step where the model is process to fit occupants, components, engine available, drive train layouts and safety requirement.

4-virtual model

The 2D sketch is transform into 3D model using 3D softwares. Now the design can be better examine while in 3D.refinement are made before passing the details drafts of the design to the next step.

5-clay model creation

Depending on the company, if 2 to 3 concept were selected after sketch generation a 1:4 scale clay model may be created before the 1:1 scale clay or all of them can be made on 1:1 scale directly then one is selected.

clay making is a step in passenger and special purpose vehicle design process. after the virtual 3D modelling the clay modelling help to sculpt the desired surface of the vehicle
6-interior design

The interior design involves the interior sketches of the vehicle. Like the exterior design many sketches can be generated, one is selected then the clay model of the interior is made. The interior design usually involves also color and trim/control and user interface concepts, infotainment system material selection etc…  

7-final model /prototype build

Once the exterior and interior design complete, that is a full size desirable clay is obtain, then a prototype of the vehicle can be build. It can be a working prototype ready for crash test or just a prototype to see how the components are fitting.

8-approved the concept and pass it to engineering

The engineering section involves further simulation on the design, crash tests, production engineering (tooling, production platform setting).

9-final approval

After successfully passing all the engineering, crash tests a new vehicle is ready for production, the final green light just need to be on by the management and in couple of days the new vehicle can be on roads.

However with the advancement in computer simulations where almost all the real case scenario can be simulate in computer some of the above steps can be remove thus reducing development time and development budget.

Special purpose vehicles design approach

For special purpose vehicles, there are more features to be included or simply there are more demands from the vehicle. Starting with aesthetic chances are we will end up not reaching our design goals, because of very tight constraints.

A special purpose vehicle can be develops as follows:

1-application definition

Special purpose vehicles are design and build for a specific goal. A formula 1, an off-road racing buggy are design and build to race. A military vehicle is design to fit a specific need.

2-suspension design
3-chassis design
4-aerodynamics design
5-cockpit or body design

One may observe that, after the application definition, the suspensions design follows. simply because for special purpose vehicles dynamics requirements are more, suspensions need to be design to satisfy the requirements thus making them very crucial in the design.

After the application definition focus is going to be on the next two steps, details views of these steps are:

-wheels layout, track and wheelbase

-suspension definition and setup (deciding the right type of suspension to use and their setup)

-chassis requirements

The first questions to ask while planning to design a chassis is under which type of loads the chassis is going to perform? There are generally 5 types of loads a chassis may be design to withstand.

  • Bending loads
  • Torsional loads
  • Combine torsion and bending loads
  • Lateral loads
  • Fore and aft load

The chassis for special purpose vehicles need to be design to have more strength and stiffness in order to resist bending forces especially torsional forces.

-preliminary chassis design

-chassis refinement

-chassis checks


– redesigning, checks, simulations, repeat till to get the appropriate one

-final refinement on the chassis and other components.

I hope you enjoy this article and you gain an understanding of passenger/commercial trucks and special purpose vehicles design process. If you like pleases comment and share, and if you will like us to cover any related topic suggest, we will do our best to satisfy your queries.

read about :Innovations in steering system design

About the author


View all posts

let us hear from you!

Your email address will not be published. Required fields are marked *