Why Do Car Manufacturers Use So Much Plastic? - ThermoPro

Why Do Car Manufacturers Use So Much Plastic?

Why Do Car Manufacturers Use So Much Plastic?

The use of plastic material has completely revolutionized the automotive manufacturing industry. So much so, in fact, that plastic is the second most common building material found in motor vehicles.

Historic materials like steel are no longer the only options for vehicle manufacturing. Plastic offers a durable, flexible and lightweight alternative that can be made into nearly anything. In addition, it is relatively affordable compared to the alternatives such as aluminum alloys or complex steels.

What Types of Plastics are Used In Car Manufacturing?

Polyethylene – Polyethylene is a strong plastic that can handle heavy impacts and maintain integrity under stress. This type of plastic is highly resistant to moisture, many types of chemicals, and is often a low cost option for manufacturing.

Polystyrene – A relatively inexpensive plastic. Polystyrene is resistant to electricity and many chemicals. This type of plastic is susceptible to UV light, but can be capped with UV resistant material to prolong lifespan. This material can be produced as both an opaque and transparent plastic.

ABS – Acrylonitrile Butadiene Styrene, or ABS, is a tough, versatile thermoplastic that can be produced in a variety of finishes. It is resistant to temperature changes and performs well even in low temperatures.

Polycarbonate (PC) – Incredibly durable with high impact strength. Because of its hardness, rigidity, and heat resistance, Polycarbonate is often used in high-stress applications. This plastic can be made with both opaque and transparent variations.

TPO – TPO compounds are resin blends of polypropylene (PP) and un-crosslinked EPDM rubber and polyethylene. This blend offers high impact strength and works well in low temperatures. Thermoplastic Polyolefin is highly chemically resistant, and is often used for industrial or demanding applications.

What are the Advantages of using Plastics in Cars?

There are a multitude of advantages to using plastics in car manufacturing instead of traditional materials. Each type of plastic offers a different way to improve the overall safety and usability of motor vehicles. One type of design will offer durability while other properties include fire resistance or weatherproofing – all depending on the design goals.
While metal in vehicle manufacturing is important there are a few major categories that plastic parts hold a significant advantage.

Vehicle Safety

Plastics tend to have a higher energy absorption capability, nearly four or five times that of metal. This provides additional safety for passengers in the event of an impact or car accident. Certain plastics are also highly resistant to fire, weather, and chemicals. This resistance prolongs the life of the vehicle and allows it to be operated safely in varying circumstances.


Swapping metal for plastics when designing a car will significantly reduce the vehicle’s overall weight. Lighter cars are faster, and typically more fuel efficient which reduces emissions. According to the EPA, every additional 100 lbs of added weight decreases a vehicle’s MPG by 1%. Less weight also helps prolong the lifespan of other vehicle components, such as the car’s battery.

Cost Reduction

The use of plastic has proven to be much more cost effective than alternative materials used in car manufacturing. Plastics are relatively inexpensive to produce, and molded components reduce production and assembly time. Reducing the cost of making vehicles allows businesses to sell higher volumes at lower prices.

Lower costs also benefit the consumer – cars can be less expensive to buy, and plastic products are easier to repair or replace. Vehicle owners spend less at the pump with lightweight designs, and weather and heat resistant parts require less maintenance.

Which Parts are Commonly Manufactured from Plastic?

Internal Components

The car interior is made for the passenger to enjoy. However, there are many aspects that use plastic for safety, efficiency and comfort.

  • Dashboards – Typically Made from ABS.
  • Seating – Made with Polyurethane.
  • Carpet Fibers and Electrical Insulation – Made from Polypropylene.
  • Interior Trim and Fuel System – Often made from Polyoxymethylene, due to its stability, rigidity, and high resistance to temperature.

External Components

Externally, we know cars, trucks and commercial vehicles have a variety of plastics utilized in the body for safety and efficiency.

  • Bumpers – Car bumpers require high impact resistance, so Polypropylene, Polycarbonate or TPO are typically used.
  • Tires and Suspension – Often made from Polyurethane, due to its suitability for outdoor use.
  • Door Handles and Headlights – Polyoxymethylene works well for both interior and exterior components on account of its high rigidity.

It’s important to choose the right material for different automotive applications. The plastics used to manufacture cars have given designers an opportunity for new designs that were not possible with metal. The use of these materials also allows companies to produce vehicles at low costs and streamlines production. Lower costs can then be passed to the consumers keeping the vehicle prices more competitive.

Well-designed plastic components not only improve the life of vehicles but also allow for sustainability in our automotive industry.


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ThermoPro was founded in 1992. We have provided thermoformed parts in office products, recreational vehicles, medical devices, scientific instruments, home products, kiosks and retail displays, and transportation.


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