A story in safety: why excavators are yellow

More than three-quarters of all excavators around the world are yellow in colour. But why?

According to Surplex — an industrial auction house specialising in second-hand machinery — the reasons incorporate safety concerns, historical developments, and deeply ingrained cultural and psychological associations.

Safety through visibility

A construction site poses inherent risks, and unfortunately, accidents are all too common. Yellow is one of the most visible colours. Both during the day and at night, the colour provides sufficient contrast — even under the dusty conditions on a construction site. As such, it serves excellently as a warning colour that signifies hazards. Both workers and bystanders are more likely to recognise the machinery on the site, helping to avoid accidents.

Who started this trend?

Caterpillar was the pioneer in adopting yellow as the colour for construction machinery. In the early 20th century, its equipment was grey — influenced by military usage. However, it was recognised that for increased safety on roads and at construction sites, these vehicles needed to sport a high-visibility colour. Thus, in 1931, the company opted for a yellow hue. An unintended consequence was branding: these yellow machines drew attention, stood out and helped people remember the manufacturer. So, it was not long before other companies followed suit.

Caterpillar used its Hi-Way Yellow until 1979. Since then, its construction machines have been driving around in a more subdued, yet visually appealing, Caterpillar Yellow. And of course, this colour is legally protected as a trademark. Since 1989, the colours black and Caterpillar Yellow have also been integrated into the modern Cat logo.

Culture and psychology

For decades, yellow has been the standard colour for construction machinery, and people therefore often associate the colour with the construction industry. Even children are conditioned to this colour scheme — for instance, toy excavators are usually yellow.

Additionally, a psychological phenomenon called “selective perception” means that people only notice certain aspects of their environment, while ignoring others (such as a non-yellow excavator). This is a result of cognitive capacity limits, as humans simply cannot process all information simultaneously. Humans also tend to perceive things in a way that confirms their existing beliefs, while at the same time ignoring contradictory information. This combination of cultural influences, early childhood experiences and psychological wiring makes people firmly believe that an excavator must be yellow.

More than three-quarters of all excavators are yellow

The colour of the construction machine depends mainly on the manufacturer. Every year the 50 largest construction machinery manufacturers — defined by their turnover from the previous year — are listed by KHL Group in the Yellow Table.

Focusing solely on the manufacturers of excavators and filtering the Yellow Table by companies making mini and midi excavators up to 13 tons, as well as large excavators over 13 tons, the data reveals that 28 out of the 50 companies create yellow excavators. In fact, more than three-quarters of all excavators sold in 2022 were yellow. To be exact: 76.2%. The second most common colour by a wide margin was orange or red (11.9%), followed by white or grey (6.2%) and green or blue tones (5.8%). These trends are also reflected in the used machinery market.

So, not all excavators are yellow — but the majority are, and for good reason. Not only does it improve safety on construction sites, but from a young age several generations of people have been conditioned to associate yellow with excavators.

Image credit: iStock.com/Avalon_Studio