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What Determines the Effectiveness of US Road Signs?

November 21, 2019

How effective are road signs across the United States? Numerous studies have been conducted over the past several decades that explore both human psychology and driver response to signs. Here are some of the findings that back up the argument that US road signs are necessary and serve an important purpose of keeping roads safe.

How Effective Signage Utilizes Human Psychology

Warning signs do not always influence a person’s behavior, according to vision and experimental psychology expert Marc Green, Ph.D., in his article “The Psychology of Warnings.” He believes there’s more to alerting drivers of dangers than selection of color, size, location, font and message. The sign designer must take into account how a warning affects driver goals, as well as the cost-benefit calculations of the viewer and their experience and knowledge of the social world.

Since humans have more similarities than differences, drivers likely have similar goals and experiences in engaging with signs. People tend to be followers of what they see other people do, so if they see others disregarding a particular sign, they may conform. The likelihood of compliance is greater, however, if drivers see other drivers responding to signs. It still comes down to the individual, as some people are more conscious of social responsibility than others.

A driver makes a cost-benefit analysis when they decide how to respond to US road signs. Every driver has goals, such as getting to a destination at a certain time, so the question becomes: how does the sign affect the driver’s goals? One of the driver’s goals is to avoid accidents, which comes into play during the cost-benefit analyis. A driver may first quickly assess the risk of disregarding the sign before deciding on compliance.

One of the factors that makes each driver unique is everyone has their own perception of danger, risks and hazards. The cost-benefit analysis process involves assessing three factors:

  1. Cost of compliance
  2. Perception of danger level
  3. Personal and social decision-making

Driver Response Tests

The Transporation Research Board (TRB), which is a division of the National Academies of Sciences, Engineering, and Medicine, publishes studies on driving behavior. A study on signs that warn “turning traffic must yield to pedestrians” at intersections found that driver yielding behavior improves with countermeasures such as advance yield markings.

Another study published in the Journal of Consumer Research found there is potential danger from drivers becoming accustomed to the word “danger.” While familiar signs may cause drivers to have a sense of security, new designs are more likely to alert drivers to pay attention. The concept of dynamic rather than static action depicted on a sign graphic can make a difference. Researchers suggest that perception of movement on a sign prepares motorists for actual movement.

Other studies have shown that dynamic action on a sign gets people’s attention quicker. This portrayal of movement leads to increased eye movement, ensuring quicker sign reaction time. Stick figures in action, for example, capture attention better than static pictures. This is one reason that dynamic signs such as our TraffiCalm products are becoming so popular.


Various studies have shown that not only are US road signs affective at grabbing people’s attention, but certain signs are more effective than others. The psychology and experience of the driver is a major factor in how well he or she complies with the sign message. Contact Zumar at our Arizona, California and Washington locations to learn more about the effectiveness of US road signs.

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