When Did Cars Start Using Safety Glass?

Automakers began installing safety glass in car windshields in the late 1920s; by 1929–1930 it was standard on major U.S. brands like Ford and General Motors, and laws in the mid‑1930s cemented its use. The shift, driven by advances in laminated glass and later tempered glass, dramatically reduced injuries from shattered panes and set the stage for modern glazing standards.

From Lab Discovery to Road Safety

The concept of safety glass predates its automotive use. French chemist Édouard Bénédictus discovered laminated glass in 1903 and patented it in 1909. Commercialized under names such as Triplex from 1912, early laminated glass saw wartime use in aircraft before migrating to cars.

Mass Adoption in the Auto Industry (1920s–1930s)

Safety glass moved from novelty to norm over about a decade. A few upscale or innovative makers offered it first, followed by the industry’s largest brands that made it standard equipment, particularly in windshields where shattering posed the highest risk.

Early adopters and industry-wide rollout

In 1926, the Rickenbacker Motor Company made safety glass standard across its lineup, a notable first among U.S. automakers, though the brand was short‑lived. The breakthrough to mass adoption came when Ford introduced laminated (Triplex) safety-glass windshields as standard equipment across its cars by 1929. General Motors followed, and by the 1930 model year its divisions had adopted nonshatterable windshield glass. Through the early 1930s, laminated windshields became typical, while tempered glass for side and rear windows gained traction later in the decade and into the 1940s.

Mandates and Standards

Regulation quickly reinforced the trend. New York enacted a pioneering statewide law in 1934 requiring nonshatterable glass in car windshields for vehicles sold in the state, and numerous U.S. states followed suit over the next few years. In the United Kingdom, early 1930s regulations (including provisions stemming from the 1930 Road Traffic Act and 1931 Construction & Use Regulations) required safety glass for windscreens on new cars. In the United States, the federal government later standardized automotive glazing through FMVSS No. 205 (first issued in the late 1960s), specifying the approved types of laminated and tempered glass and where they must be used.

What “Safety Glass” Means in Cars

Two technologies underpin the term “safety glass,” each tailored to different parts of the vehicle for both safety and durability.

Laminated glass

Laminated glass sandwiches a plastic interlayer (typically polyvinyl butyral) between two sheets of glass. On impact, it cracks but stays bonded, reducing lacerations and maintaining a barrier. It has been used primarily for windshields since the late 1920s and remains mandated for that position in most markets.

Tempered glass

Tempered glass is heat-treated to increase strength and to shatter into small, less injurious granules. It became common for side and rear windows from the late 1930s onward. Modern vehicles may also use laminated glass in some side windows for added security and noise reduction.

Key Dates at a Glance

The following timeline highlights the major milestones that explain when safety glass moved from invention to industry standard and legal requirement.

• 1903–1909: Édouard Bénédictus discovers and patents laminated safety glass.
• 1912: Triplex-branded laminated glass enters commercial production; early use in aircraft.
• 1926: Rickenbacker makes safety glass standard across its car lineup in the U.S.
• 1929: Ford makes laminated safety-glass windshields standard across its models.
• 1930: General Motors adopts safety glass windshields across its divisions.
• Mid-1930s: Laminated windshields become typical industry-wide; tempered side/rear glass spreads.
• 1934: New York passes a statewide law requiring nonshatterable glass in car windshields; other states follow.
• Early 1930s (UK): Regulations require safety glass in windscreens of new cars.
• Late 1960s (U.S.): FMVSS No. 205 establishes nationwide standards for automotive glazing.

Taken together, these milestones show that while the invention dates to the early 20th century, the practical answer for widespread use in cars is the late 1920s, with legal mandates solidifying the practice in the mid‑1930s.

Bottom Line

Automakers started putting safety glass in car windshields in the late 1920s—most notably Ford in 1929 and GM by 1930—with state and national regulations in the mid‑1930s and beyond ensuring universal adoption. Laminated glass became standard for windshields, while tempered glass followed for side and rear windows, forming the basis of modern automotive glazing.

When did the safety glass come in?

This was Triplex glass, made out of “two sheets of thin or semi-thick glass joined by pressure and gluing to a thin core of celluloid or composite materials”. Bénédictus patented his invention in 1909 and founded the Triplex Glass Company in July 1911. This produced “safety glass” and licensed it abroad.

When did safety glass become standard in cars?

Safety glass became standard in all car windows by the 1950s, though laminated safety glass was used in windshields by the 1920s, with a 1937 law requiring its use in all vehicles in the U.S.. While laminated glass was standard for windshields and tempered glass for side and rear windows, a 1966 federal law mandated shatter-resistant windshields and the 1970s saw the creation of the NHTSA to set formal safety standards for all car glass.
 
Key Dates in Safety Glass Adoption

• 1903: French scientist Édouard Benedictus invented laminated glass, which was patented in 1910 as Triplex. 
• 1919: Henry Ford began using laminated glass in his cars, as a safety feature to reduce injuries from flying glass. 
• 1920s: Laminated safety glass became a standard feature for windshields in many vehicles, with the automotive industry adopting the technology to prioritize passenger safety. 
• 1930s: Tempered glass, a type of glass strengthened by heat, was introduced for side and rear windows to prevent shattering into sharp shards. 
• 1937: The U.S. made safety glass a compulsory requirement for all automobiles. 
• 1940s–1950s: Safety glass became standard for all car windows, including the front, side, and rear. 
• 1966: The U.S. Highway Safety Act mandated shatter-resistant windshields. 
• 1970: The National Highway Traffic Safety Administration (NHTSA) was founded, leading to the establishment of formal, nationwide safety standards for automotive glass. 

Were tempered shatterproof glass in cars before 1960?

Tempered glass windshields were the standard in the industry until the 1950s-60s, that’s when multi-layered laminated glasses started to replace them. These are similar to tempered glass but with one key difference; they bend a little if there is any pressure.

What year did tempered glass come out?

Tempered glass was invented in 1874 by François Barthélémy Alfred Royer de la Bastie in Paris, France, who patented a method of heating glass and then rapidly cooling it to create a stronger product. The concept of tempering glass, however, has earlier roots, with the discovery of Prince Rupert’s Drops around 1660, a form of glass that exhibits similar durable qualities. 
Here’s a breakdown of the key developments in tempered glass:

• 1660: Prince Rupert of the Rhine demonstrated the existence of “Prince Rupert’s Drops” to King Charles II. These teardrop-shaped pieces of molten glass, cooled rapidly in water, are incredibly strong but shatter explosively if the tail is broken. 
• 1874: François Barthélémy Alfred Royer de la Bastie developed the first patent for a tempering process. His method involved heating glass and then quenching it in a hot bath of oil or grease, creating a stronger, more resistant glass. 
• 1877: German inventor Friedrich Siemens developed an alternative method known as “compressed glass” or “Siemens glass,” where he pressed hot glass into cool molds, resulting in a stronger product. 
• 1930s: Large-area flat tempered glass began mass production, particularly for automobile windshields, in France, the United States, and Great Britain. 
• Post-1970s: Major advancements in tempering technology, such as the ability to temper thin glass, led to wider promotion and popularization of tempered glass worldwide.