Mises Wire

Yes, Car Seat Laws Reduce the Birth Rate

car seat

Opponents of the Trump campaign are having fun this week with some year-old comments from vice-presidential candidate J.D. Vance. Apparently, in a Senate hearing during March 2023, Vance stated that car seat laws have an impact on the number of children parents feel they can afford. As quoted in the Ohio media site cleveland.com:

“I think there’s evidence that some of the things that we’re doing to parents is driving down the number of children that American families are having,” he said. “In particular, there’s evidence that the car seat rules that we’ve imposed -- which of course, I want kids to drive in car seats -- have driven down the number of babies born in this country by over 100,000.”

Anti-Trump activists got to work mocking the idea, and some suggested that Vance must have simply made these numbers up. 

Most of the mockery was based on the idea that a $100 or $200 dollar car seat is surely not the deciding factor in whether or not to have another child.  This claim may seem perfectly plausible to anyone who has never had children or has only had one or two small children at any given time. Anyone who has actually considered having a third child, however, knows that the cost of the car seat itself is not what dissuades parents from having an additional child. 

Rather, the realities of car seats and car-seat laws mean that a third child adds significant costs and obstacles in the form of a necessarily larger car. As anyone who has three small children knows, it is difficult to fit three car seats in the back seat or an ordinary car. This is why so many people with more than two children end up buying a minivan—which is more costly than a small sedan. The third row of seats is often necessary to accommodate a third car seat. Or, in some cases, the problem may be addressed with a large vehicle, such as a costly full-size SUV, that is sufficiently wide to accommodate a third car seat. 

Anyone who isn’t wealthy and who owns small cars has encountered this problem. When it comes to having a third child, it often becomes necessary to purchase a larger, more expensive car. This is about much more than the cost of a single car seat. 

This has been known for years among more honest researchers. For example, a 2020 study by business professors Jordan Nickerson and David Solomon plainly notes this challenge of finding a back seat in a vehicle that accommodates three car seats. 

This is further complicated by the fact that many states continue to increase the age at which children can legally “graduate” to using the standard seat belt. This means that as mandates have required older and older children be secured by car seats, more car seats are required for longer periods of time. The ikelihood of needing three car seats at one time increases. 

It is reasonable to conclude from this that, at the margins, this will have an effect on the number of children parents elect to have.  So, it is hardly shocking that the Nickerson and Solomon study concludes that car seats have an impact on fertility rates. They write: 

We show that laws mandating use of child car safety seats significantly reduce birth rates, as many cars cannot fit three child seats in the back seat. Women with two children younger than their state’s age mandate have a lower annual birth probability of 0.73 percentage points. This effect is limited to third child births, households with access to a car, and households with a male present, where both front seats are likely to be occupied. We estimate that these laws prevented 57 children’s car crash fatalities in 2017, but prevented 8,000 births that year, and 145,000 births since 1980. 

This study, with its “145,000” number, is likely the source of Vance’s comment on how car seats have driven down the total number of babies born. 

Oddly, the authors, when questioned by the media, “specifically said they were not advocating car seat regulations were driving down birthrates.”

Really? It’s hard to see why the authors would say this other than to just avoid being caught up in a political controversy. After all, their article is not exactly ambiguous on this point. They write: 

We document a large and perverse effect whereby child car seat mandates have the unintended consequence of large reductions in birth rates. This effect is identified by combining state and year variation in mandates with the outsized cost of having a third child in a car seat. We estimate that these laws are currently preventing approximately 8,000 annual births, around 141 times greater than plausible estimates of the number of lives saved in car crashes.

Not only do Nickerson and Solomon conclude that car seat laws have “the unintended consequence of large reductions in birth rates,” they also suggest that the costs imposed by these mandates likely exceed the benefits by a large margin. 

Nickerson and Solomon base much of this additional conclusion on studies that show that the added benefit of securing children over two years of age in car seats—as opposed to simply using seat belts—are very small. Specifically, they quote a 2008 study by Steven Levitt in the Review of Economics and Statistics, and a 2006 study by Levitt and Joseph Doyle published by the National Bureau of economic Research. 

Levitt concludes

Over the past thirty years, the use of child safety seats in motor vehicles has increased dramatically. There is, however, relatively little empirical evidence regarding the efficacy of child safety seats relative to the much cheaper alternative of traditional seat belts. Using data on all fatal crashes in the United States from 1975 to 2003, I find that child safety seats, in actual practice, do not provide any discernible improvement over adult lap and shoulder belts in reducing fatalities among children aged two to six. Lap-only belts are somewhat less effective, but still far superior to riding unrestrained.

In their related study, Levitt and Doyle similarly write

Our evidence suggests that lap-and-shoulder seat belts perform roughly as well as child safety seats in preventing serious injury for older children [aged 2-6], although safety seats tend to be better at reducing less serious injuries. Lap belts had somewhat higher injury rates, while no restraint is associated with much larger injury rates.

The older and larger the child is, the less significant are the benefits of additional child-safety restraints. Yet, many states now mandate that children as old as seven may not legally use the vehicle-provided seat belts. Some states require the child be eight years old. This is a sizable inflation of mandates from earlier (pre-1980) laws that focused primarily on very small children. 

Yet, some critics of Vance’s comments would have us believe that the costs associated with these mandates have no effect at all on a decision to have additional children. This may seem rcredible to wealthier commentators or dual-income-no-kids (DINK) couples who know nothing about the real-world constraints experienced by working-class or middle-income people when it comes to raising children.

In the real world, however, the likelihood of people doing Thing X—in this case, having a third child—is smaller as the cost of doing Thing X rises, all else being equal. If this weren’t the case, then people wouldn’t switch from buying steak to buying ground beef as the price of steak rose. Yet, in recent years, countless people of ordinary means have lived out this phenomenon in real life. Simply put, people change their behavior as the relative costs of various activities change.

Those who mock Vance on this topic, however, would have you believe that people are completely unmoved by the prospect of having to buy a larger car in case of having a third child. This is simply not a serious claim. 

There is also a likely ideological bias here beyond the current political campaign. Those who favor further expanding car seat laws tend to be found on the Left. The ideological Left is also the place where we tend to find a bias in favor of population control, falling birth rates, and published articles about the benefits of being “childfree.” (It is no secret that self-identified conservatives have more children.) It may very well be that many on the Left simply view car-seat laws’ negative effect on fertility as an additional benefit of the mandates. 

Those who claim that additional mandates for car seats are good thing “if they save even one life” are also embracing an unrealistic view of the world. For one, if there is no acceptable limit to adopting ever greater levels of safety—with no regard for the costs and trouble involved—we should all be advocating for 5-point harnesses and helmets for every person in every car. Yet, most reasonable people reject this. 

Moreover, as we’ve seen from the above research, even when it comes to car seats for older children, the safety advantages—compared to what must be given up in return—are very small. Yet, these additional car seat mandates are imposed on all parents because a small number of politicians have imposed their own personal feelings about safety on others. 

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