Saturday, September 19, 2009

New website: We Are Colorblind

Special thanks to Daniel Flück of for this guest post.

Tom van Beveren from the Netherlands put together a very comprehensive site on all sorts of stuff people should know, if they want to build/design a website which doesn’t exclude colorblind visitors. Because almost 5% of all people are suffering from some form of color vision deficiency, this is something every web publisher should care about.

we are colorblind

The site We are includes a lot of very interesting topics related to color blindness on the web. It is structured as follows:

Patterns for the Color Blind:A list of very useful patterns you can follow while you’re designing your web content. If you follow those patterns, colorblind people will definitely find their way around on your page.

Quick Tips: This section provides supportive information for all the patterns from the above mentioned list. If you dig into the quick tips you’ll learn more on how color blind people see the world and how you can use this information.

Color vision and web Tools: Hopefully this is an ever growing list of great tools to help you while you are building your web site or just on your way through the web.

Good and bad online Examples: The examples section gives a good overview of good solutions, which help people with color vision deficiency. The list also includes bad examples; web sites unusable by color blind visitors.

If you think about building a new web page, redesign your site or get your online content ready for colorblind visitors, make sure you visit and follow the tips and patterns provided by Tom.

Wednesday, September 9, 2009

THIS is why we're here

I've been writing articles for Grey Means Go since the beginning of the year, starting with a post entitled Why are we here? In it I briefly discussed color vision deficiency and its effect on transportation safety. The answer to the "why" question was simply to elevate this discussion.

I was wrong (or at least incomplete).

What had not occurred to me was shared in an e-mail I received a few weeks ago, in response to a blog post on the new Huetility iPhone app:


My son is colorblind and wants to be an engineer. I have been searching the internet for programs (i.e. the eye pilot) and came across this iPhone app. I know it won't help my son directly, but it brings attention to the need to know there are people who cannot see color and helps various industries design their programs so so my son isn't affected.

Thank you soooo much...It is people like you that keep my son still in the game. My son is completely colorblind and very good at math and wants to help people. I want him to be able to contribute to society and share his mathematical and scientific strengths.

Thank you again...thank you so very much...


To be perfectly honest, this had not crossed my mind. The fact that this small effort can inspire others (particularly kids) is very cool. I'm confident that Stacy's son can contribute as much as he desires, regardless of how well he can tell red from green.

Tuesday, August 11, 2009

Innovative treatments on Houston's Red Line

The Red Line is a 7-mile stretch of light rail in Houston, Texas, that includes a high number of rail-highway crossings. A number of crashes have occurred on the Red Line involving cars and light-rail vehicles, with one crash resulting in a fatality. One potential cause of crashes is motorist's lack of compliance with traffic signals, partially due to limited visibility of those devices.

Houston METRO and the Texas Transportation Institute (TTI) are evaluating supplemental treatments to increase visibility at the signals, and hopefully reduce the number and severity of crashes. Though color vision deficiency is not explicitly mentioned in the article, the specific treatments should have a significant effect on colorblind drivers.

Red Illuminated Backplate
Light emmitting diode (LED) backplates have been added around the traffic signal heads to increase the conspicuity of the traffic signal. The difference between this application and the reflective backplates discussed on the blog (in Kentucky and Quebec) is that the red outline on the backplate is illuminated only when the traffic signal indication is red.

Illuminated Stop Bar
Similarly, a line of LED lights is placed in the pavement in front of the traditional white painted stop bar. The red pavement lights turn on when the traffic signal indication is red, and remain off at all other times.

According to the Texas Transportation Research article, early indications show both treatments having a positive effect on motorists. Additional evaluation will be conducted this year before completion of the final report.

This is yet another example of a treatment providing a significant benefit to colorblind motorists while also having a positive effect for all other drivers.

Friday, July 10, 2009

Grey Means Global: Taking the message overseas

I've been fortunate to have Grey Means Go articles published in a variety of forms over the past few weeks, both local to international.

Columbia Missourian

My hometown newspaper in Columbia, Missouri, published a recent Grey Means Go blog on the bank drive-thru experience. In addition to the paper copy, the article is available on a website they've devoted to local writers: My Missourian.


At the other end of the spectrum, a colleague from The Netherlands recently translated a Grey Means Go article to Dutch and posted it to his website, Kleurenblind. Jurjen van Bolhuis has developed a site discussing colorblind issues in his country and around the world.

Readers around the world

I took a look at the readership of Grey Means Go and discovered the site has readers all over the globe. Of the last 500 page loads, 42% came from outside the United States, from as far away as Egypt, Singapore, and Lebanon.

These recent examples have urged me to think more about the global community and content sharing across languages. It seems that expanding beyond English-speaking readers is an important step to promote growth. I am embarrassingly mono-lingual, but I hope to learn more about available tools to share the message of Grey Means Go more effectively around the world.

Tuesday, June 16, 2009

Bank Drive-Thrus: Bane of the Colorblind Driver

I've often run into this situation at the bank drive-thru. I pull up, look at the lights above the lanes, and I can't tell for sure if the lane I want is open or closed. At this bank on my way home from work the green light is always on the right. As long as I remember that, I'm OK.

The other work-arounds I typically use:
  1. If there are other vehicles, I'll get behind one. Sure, I passed up a number of open lanes with this strategy, but I never pull up to a closed one.
  2. Always, always go to the window. If the drive-thru is open, the left-most lane is always open.
But I've found a better solution.

This drive-thru near my home developed a simple sign that is easier for all to see, and provides a significant benefit for color deficient drivers.

(Note the OPEN sign is on the left at this location)

Brilliant. If we were in 1992 and I still used the bank drive-thru (vs. online banking and the ATM, neither of which is ever closed), I'd seriously consider switching banks for this reason alone. Nice work, Boone County National. You've secured my hypothetical, fourth-dimensional business.

What other everyday, driving-around-town experiences have you had like this? I tend to forget about them since I've "worked around" them for so long, but I'm sure there are other common stories. Let me know.

Friday, June 5, 2009

See through colorblind eyes - new iPhone app

You can see what colorblind people see with a new iPhone app releasing this weekend. The Huetility Colorblind Simulator, the first of its kind on the iPhone, was designed to accurately model the different types of colorblindness.

According to the developers, Huetility simulates the different types of colorblindness so a user can compare the different views.
  1. Normal color vision

  2. Colorblind view (including red-green, blue-yellow, and complete color loss)

  3. Error view highlighting the regions of the color image likely to cause a colorblind viewer the greatest problems.

The app is intended for designers, content creators and iPhone game developers who want to check that colors they have used are colorblind friendly. I foresee application to the world of transportation as well.

The most promising piece of the app, in my opinion, is the ability to take a picture with the iPhone and then see how that photo looks to a colorblind person. An engineer could take photos of traffic signals, signs, and other traffic control situations to learn how the design works for coloriblind road users.

Deal of the Day

The creators of Huetility have been generous enough to given Grey Means Go readers three free iPhone downloads. So here's the deal: the first three readers to send an e-mail to with "Huetility" in the subject line will receive a code to download the app for free. I'll announce the winners next week.

If you don't get a free copy, Huetility is priced at $2.99 and can be downloaded HERE.

I'm very interested to hear comments from readers after you download and use this software. I have high hopes that it will be beneficial as we continue the relation of colorblindness to transportation. Please check it out and post your reviews here.

Friday, May 29, 2009

Can colorblind drivers see bicyclists?

Drivers often find it difficult to see bicyclists on the road, so extensive efforts have been made to increase bike-riders' conspicuity with hats, vests, jackets, and other high-visibility clothing. The researcher took a look at the color used for this apparel (often fluorescent green, pink, or yellow) to determine if it was visible to those with color deficient vision.

The results were neither statistically significant or overwhelming, but the author raises some interesting questions about the assumptions made by those producing, selling, and using high visibility garments. A photo example, using the Vischeck website to simulate color blindness, is telling:

The screenshot is from a website promoting high-visibility garments for kids. The "regular vision" screenshot is on the left. The "color-blind" simulation is on the right (I think).
I'm hoping this turned out well, because being colorblind, they look pretty much the same to me. I guess that's the point. According the author (whose word I'll take on this one),
"...most of it just doesn't work for people who are color blind. The
high-visibility green and orange hats become a light color that blends well with
the trees. The hot pink becomes grey."

I once led my state's work zone safety efforts for the Department of Transportation. It never dawned on me that I was seeing high-visibility vests very differently than those who were relying on them to stay safe in highway construction zones. With upwards of 5%+ drivers suffering from some color vision deficiency, it seems that colors most visible to the colorblind driver would be the most appropriate to use.

For the full report from Mr. Sullivan, click here.

Saturday, May 23, 2009

A great colorblind website

Daniel Flück of Zürich, Switzerland, started Colblindor in 2006. It is a great overall website on colorblindness and how we as colorblind people deal with this deficiency.

The site includes colorblind tests, news, and tools to support life with color deficiency.

I highly recommend checking the site out when you get a chance:

Grey Means Go: An Introduction

The issue of color vision deficiency been largely ignored by transportation professionals. An estimated 6-12% of the male population has some sort of colorblindness, meaning roughly 5% of road users are affected. The effects are not well documented, but what is known is that color deficient drivers suffer a disadvantage on the roadway.

The topic is important because 90% of what drivers use to navigate is visual, and much of that information is color-specific. Traffic sign types are denoted by color, and pavement markings in the United States have different meanings if they are striped white vs. yellow. Traffic signals’ red and green indications -- the two colors most often confused by color-deficient individuals -- provide drivers with opposite messages: Red means stop. Green means go.

But to a color-deficient driver, and even more so to a true color blind driver, the colors have little or no meaning.

Grey means stop. Grey means go.

The purpose of Grey Means Go is multi-faceted:

1. Describe the problem and share the small amount of research literature available on color deficiency in transportation and advocate for additional studies on the topic.

2. Share best practices that have been implemented – mostly outside the United States – to help colorblind drivers:

3. Encourage transportation professionals to consider color-deficient road users during design, construction, and operation of transportation facilities.

4. Encourage readers to share their stories of driving with color deficiencies, with the hope of increased community and discussion of this important issue.

So please take the time to read through the blog, make comments, and tell your stories. How does colorblindness affect you on the road?

I'm also always looking for guest bloggers, so feel free to contact me directly via e-mail at

Friday, May 8, 2009

Helping colorblind drivers helps everybody

I previously referenced this study from the Kentucky Transportation Center regarding a number of low-cost safety measures for signalized intersections. Here's the complete document:

I took a closer look at it this week and noticed something interesting. A number of colorblind-friendly treatments also provided an overall benefit to the safety at signals.

Double Red Lights

This application creates a "Red T" at the top of the signal head. It's main purpose is to double the visibility of the red indication. For colorblind drivers, it provides additional information that it is the red indication (in addition to its placement at the top of the signal).
  • Total crashes down 2 per year
  • Angle crashes down 1.7 per year
  • Rear-end crashes up 0.5 per year

Advanced Warning Flashers

I had not thought about this one before as a significant colorblind benefit, but I believe it could be. There are times that I don't always know if what I'm seeing three blocks ahead is a traffic signal or just ambient lighting from other sources. Signal Ahead signs (and particularly those discussed in the report with actuated flashers) give me the additional information I need to know what is coming up.

  • Total crashes down 1.4 per year
  • Angle crashes down 0.7 per year
  • Rear-end crashes down 0.6 per year

Reflective Backplates

Backplate installation showed a crash reduction benefit for ALL drivers by adding conspicuity to the traffic signal.

  • Total crashes down 1 per year
  • Angle crashes down 0.4 per year
  • Rear-end crashes down 0.3 per year
Crash Data

Though the reductions seem small, it's important to keep in mind the cost was also very low for these treatments. And though 0.5 crashes per year might sound insignificant, if multiplied times an entire state DOT or large city signal system (sometimes thousands of intersections), significant reductions could be achieved.

The best implementation plan may be modifying policy so any new signal installations (or updgrades) are put in with these measures. High crash locations could also be added to the mix, so that eventually every signal includes these improvements or something similar.

Friday, April 10, 2009

1879: Color-blind Train Engineers Fired

In 1879 the New York Times published some of the earliest articles related to color-blindness and transportation. Since this time period was for the most part pre-automobile, the discussion focuses on train engineers and their abilities (or lack thereof) if they suffer from color deficiencies.

The discussion in these articles is a response to European countries (Switzerland, Italy, France) that had tested their locomotive engineers for color-blindess and discharged from service those testing positive.

January 26, 1879
"To a color-blind person any color that looks dark seems red, a brighter color seems green, and a color still brighter appears white. Test a color-blind engineer, and he will, in many cases, tell the signals at once, for if he sees a dim light he knows that means stop...He is guided merely by the intensity of the light."

This is a relatively accurate description of how I perceive Red-Yellow-Green traffic signals, using intensity (combined with placement) to support my deficient ability to discriminate the colors.

"Mr. Leonard...was then asked to pick out different shades of the same color, and, as he is affected with color-blindness, he placed in a mass shades of all colors - blue, green, and red - to the great amusement of the committee and spectators."

Wait...what? To the great amusement?

September 3, 1879
"Complete protection against this source of danger [color-blindness] can be secured only by eliminating from the employes of railroad companies and other passenger carriers all persons whose duties require perfect color perception, and who are deficient in this respect."
"Every railroad employe should be carefully tested for color-blindness by a competent expert, and all found deficient should be removed from posts of danger."
I don't know how the railroad companies handle this issue now, but it's very interesting to see the "remove from post" attitude of 1879.

November 30, 1879
"[Color-blind engineers] have a specially acute perception of the luminosity of colors and they will distinguish red and green not as red and green, but as differently strong. In this way the railway engineer may go on safely for years, distinguishing the red and green lanterns by their brightness. But finally comes a night when their relative brightness is altered by moisture upon the glass, by snow, or hail, or dust, and then the mistake is made, te crash follows, which the least glimmer of red perceived as red, or of green perceived as green, would have avoided."

There seemed to be a general sense of fear, that the color-blind engineer was unable to operate safety in all conditions and should be removed from service. An extrapolation of this theory would question whether color-blind drivers should be operating motor vehicles on today's roads. Thoughts?

Monday, April 6, 2009

Retroreflective Backplates - Frankfort, KY

I have the pleasure of speaking about traffic safety in Kentucky later this month, and I've been in contact with some of their engineers. I had heard about some retroreflective backplates in the state, so I received some information from the transportation officials.

Notice the huge difference between the signal heads. The signal on the right, particularly for one with color-deficient vision, could be any number of lighted roadway items (or even something else). It is so much easier to distinguish the others as traffic signals, and to show you that the TOP (red) indication is lit.

Here is another application where they did not fully outline the signals, but put strips around. Officials in Kentucky told me this application does not appear as effective at night (but I wanted to show it anyway).

In May 2008 the Kentucky Transportation Center completed a research report on low-cost safety countermeasures, including various alternatives of traffic signal backplates (yellow backplates with black heads, yellow backplates and yellow heads, etc.). The report can be found here:

Wednesday, March 4, 2009

Red vs. Yellow Tail Lamps

(Left Side: Red Tail Lights. Right Side: Yellow Tail Lights)

I recently received a study from New York regarding lamps on the back of vehicles. As you may or may not be aware, both tail lamps and brake lamps are required to share the same color (red), even though the two lamps serve different purposes.

"...the functional purpose of tail lamps is to indicate the vehicle's presence
and width. The functional purpose of brake lamps is to indicate braking."
The researches proposes that changing tail lamps to yellow would be beneficial for two important reasons:
  1. It would increase the visibility of vehicles in normal driving conditions
  2. It would give following drivers two distinct messages: Yellow = Vehicle. Red+Yellow = Slowing/Stopped Vehicle.

The study peformed measured reaction times (RT) of the two scenarios: red tail lamps vs. yellow tail lamps. Results indicated significantly faster reaction times when vehicles had yellow tail lamps.

The study made me think about how this would affect colorblind drivers. When I (red/green CB) looked at the images in the report, I could see the yellow tail lights much better than the red. For me, red tail lights often blend into the vehicle itself -- especially during day or dusk conditions.

But I was then concerned that the yellow tail lights might be too bright, and their presence would detract from the more important message the red brake lights provide: Slowing/Stopped Vehicle.

To take it another step, for a driver with true color blindness I don't know that it would matter - if the brightness of the colors was the same.

Just more to think about as the issue of color is addressed in the research community.

Reference: McIntyre, S.E. (2008). Capturing attention to brake lamps. Accident Analysis & Prevention, Vol 40(2). pp. 691-696.

Wednesday, February 18, 2009

Reflective Backplates - Crash Reduction Factor

According to the FHWA/ITE Toolbox of Countermeasures, published in August 2008, adding retroreflective sheeting to traffic signal backplates can reduce all crashes as much as 15%.

The point: Many countermeasures beneficial to color-deficient drivers are also of benefit to ALL drivers.
The Toolbox of Countermeasures for intersections can be found here:
An abstract of the referenced study, a TRB paper and presentation from Canada, is here:

Thursday, January 29, 2009

Shaped signal heads to aid colorblind drivers

This signal in Hallifax, Nova Scotia, incorporated various shapes to its traffic signals. This enhancement provides additional information to all drivers, and particularly helps colorblind road users traveling through the intersection.

It seems that a number of other countries have designed roadway elements and traffic control with colorblind users in mind. Unfortunately, consideration for colorblind drivers is rare in the United States.

Wednesday, January 28, 2009

A Signal Solution from Quebec

In Quebec, the authorities have developed a way to help colorblind drivers determine when the signal is red. The signal has two red indications, one on each side. All other indications (green and yellow balls, and any arrows) have a single indication.
Also note the reflectorized outline around the signal backplate. That low-cost countermeasure for colorblind drivers provides a significant benefit to all by increasing the conspicuity of the signal.

Monday, January 26, 2009

Colorblind Glasses

Apparently the problem was solved decades ago with the introduction of colorblind glasses. It's simple, really. As the article points out, the glasses block all green light from entering the eyes. Therefore, a colorblind driver knows that if he sees any light, it must be either red or yellow.

Yikes. Now, instead of a driver having some color confusion as he enters an intersection, he has true color blindess. Hopefully the vehicle in front of him isn't green.

This doesn't even get into issues like bulbs being burned out or other signal failures.

Luckily these didn't take off, and we're left to search for additional creative ways to help colorblind drivers navigate our roads.

Tuesday, January 20, 2009

Color Blindness & Green Traffic Signals

A 2003 Minnesota DOT study took a look at the color blindness affect with regard to traffic signals. The researchers specifically studied a green LED signal indication.

For quick background, states began installing Light-emiting diode (LED) traffic signals in the late 1990s. The LED bulb provides significant energy savings and longer life.

The problem was that the clear cover over the green indication "lit up" under direct sunlight. Because it appeared bright, it appeared to be ON to colorblind drivers, and it was so much brighter than the red or yellow indications that drivers would assume the signal was telling them to GO.

A person with color vision deficiency tends to use brightness - not color - as his most important cue at traffic signals (and a number of other situations). I personally tend to see green indications as bright white. This is usually not a problem, but can become one in the scenario discussed in this paper (I can also have trouble if there is a lot of background lighting - either street lights or advertisements - in line with the signal heads).

Minnesota DOT conducted a quick study (four colorblind participants and four non-colorblind) to test the theory that the current installation could be confusing to colorblind drivers. They found that 25% of the time the colorblind participant erroneously saw the green light ON when it was not (non-colorblind participants made this mistake less than 4% of the time).

The Minnesota short-term solution was to replace their clear covers with colored ones, which will hopefully make the green indication much less bright in direct sunlight. But the inherent problem remains that colorblind drivers (estimated at up to 5% of the population) are generally being ignored in traffic signal design, where color is the most important factor in keeping motorists safe.

See the full article here:

Thursday, January 15, 2009

Why are we here?

The initial purpose of this blog is to share information and faciliate discussion about the needs of colorblind drivers, bicyclists, and pedestrians.

The percentage of colorbind people in the world is an oft-debated subject, as very few people are officially tested for color blindness. It's typically discovered by the individual themselves as they have trouble with certain color-related areas of life.

I'm a Traffic Safety Engineer and I'm red/green colorblind. Though I've worked in the transportation industry for over a decade, it has been rare to see an article, research project, or conference presentation on this issue. It is my hope to elevate the discussion and eventually improve roadway design and operation to improve the experience of colorblind roadway users.