This guest article continues SRN’s “Ask an Engineer” series with Dave Sander, CPST-I and engineer (formerly with Evenflo). This series gives an insider view of how CR engineers develop and design CRs, as well as new insights into CR functionality.
Boosters in bright colors have been on the market for a while, but have you ever wondered why CRs with harnesses don’t come in a variety of colors? I’m talking about the plastic shells, not the pads. As you might have noticed, that plastic is nearly always black, white, or a shade of gray, sort of like what Henry Ford famously said about his Model Ts, paraphrased above. And there’s a reason for that!
A CR’s color comes from what engineers call colorant. Colorant, in the form of concentrated colored plastic pellets (as shown in the photo, right), gets added to the plastic material that forms the CR’s plastic shell. The colorant of a CR is roughly 2 percent of its material makeup—the other 98 percent being high-impact plastic resin, usually polypropylene.
Even that small amount of colorant can affect the performance of the CR. And, since different colors have different chemical makeups and may require slightly different amounts of colorant, the overall composition of a CR varies depending on the color, which means that its crash performance could also differ. And therein lies the rub: If variable coloration leads to variable performance, then it also leads to more testing. For even one extra color, the amount of testing required is at least doubled, since every test performed would need to be repeated on the model in the new color, as well.
Now, you may wonder, “Wouldn’t that be worth it to make a CR that’s a marketing standout?” Well, the potential popularity of the plastic color would have to make up for the cost of roughly 200 additional tests, depending on the CR type. Besides the fact that sled testing itself is costly (about $700/seat/test, using an external lab), each test must be done on a new CR. So it is unlikely that the extra sales generated by additional plastic colors could offset the cost, time, effort, and risk of doing all the required additional testing.
How could one CR require 200 tests? Believe it or not, that is roughly how many tests it takes to prepare a CR for market (and that’s after a lot of testing in the development stage), because it has to be tested under every usage variation with every crash dummy approved for riding in it. Naturally, when a CR can be used in multiple modes, there are more tests needed.
For example, let’s say a manufacturer molds an all-in-one CR in tried-and-true black. Now the engineers have to fulfill the company’s plan for testing new CRs before the new model can be sold. Of course, the plan would include testing in RF, FF, and booster modes. For each of the modes, separate tests must be performed using each of the allowed installation methods (lap-only, lap-shoulder, and/or LA attachment); for FF mode, each of those tests must be done with and without a tether. Every one of those tests must be repeated for each of the CR’s use variations, such as in multiple recline positions. Then all the tests must be performed again for each of as many as six to seven test dummies, depending on the CR’s usage range. And that’s just the NHTSA-required testing; most manufacturers would not send a CR to market these days without doing additional testing, such as for side impacts and structure. So each of the configurations run for a frontal collision must be run again for these variations. You can start to see how the number of sled tests grows exponentially due to today’s market demand for functional variations, multiple modes, and extended use ranges.
So, now that you understand how much testing goes into one CR shell, imagine what it would mean to make the same seat in a different color, like red. Although it’s the same CR, the version with red colorant would have to be tested again according to the company’s test plan—so that’s 200 more sled tests. In this hypothetical situation, a manufacturer would have to test the CR design 400 times just to have two different colors! And that’s only crash testing; there’s also a battery of other tests that must be done, such as cycle testing, drop testing, and handle-strength testing.
All of this assumes that there is test success on the first try. Test failures require corrections, and then all the testing must be done again. And this retesting cycle is dramatically complicated by the presence of multiple colors. Using our example, let’s say the red CR fails the initial round of testing after the black one has passed. This is a real possibility. As explained earlier, the colorant is only a small percentage of the material makeup, but it can have significant impact on performance of the car seat. Think of a crash test as an amplifier; a crash test takes that small quantity and amplifies its effect.
So, the CR developers would have to go to work to make modifications until the red CR can pass all the testing. But consider this: Once the modified red CR successfully passes testing, the engineers have to start all over with testing of the black CR to make sure that what they changed for the red CR doesn’t have a negative effect on the black one. See how this could turn into a CR-testing version of a vicious circle?
When you consider all this care that’s taken to ensure a CR is safe before putting it on the market, it’s clear that making the CR in one color is challenging enough. Tackling two colors could make one’s head spin! While a company may be willing to take this on for something simpler to test, like a booster, offering multiple colors is not a rational approach for the more complex models with harnesses.
So, the next time you wonder why CR offerings aren’t more colorful, think about how much effort it takes just to make them in one color. And remember, the manufacturers’ marketing teams work hard to offer padding in an array of appealing colors—which covers up much of the plastic anyway!
—Dave Sander