Here's a 2000 study someone posted on twitter about "Injuries Associated With Bicycle-Towed Child Trailers and Bicycle-Mounted Child Seats" which is the first I've ever seen on the subject.
When compared with bicycle-mounted child seats, there were fewer reported injuries to children associated with the use of bicycle-towed trailers. Motor vehicle involvement and need for hospital admission were similar among injured children in both groups, and the head or face was the most common site of injury. These data imply that ongoing surveillance efforts to identify injuries associated with use of bicycle-towed child trailers are warranted and that bicycle helmets should be worn by children riding in bicycle-towed child trailers and in bicycle-mounted child seats.
the annual injury rate [ related to bicycle-towed child trailers] can be estimated as 0.2 per 100,000 children younger than 5 years. The annual injury rate for bicycle-mounted child seats is estimated at 1.3 per 100,000 children younger than 5 years.
The reasons for more bicycle-mounted injuries are feet in the wheels, and falls from the bike. I feel like with our bike-mounted seat the kids can't get their feet in the spokes if they tried to.
I'd been told that inside the roll cage of a trailer, kids don't really need a helmet. And when I look at the types of injuries kids sustained I can see why I was told that.
Contusions or abrasions were the most frequent injury: this was the diagnosis in 5 (83%) of the injuries related to bicycle-towed child trailers and for 20 (47%) of the injuries associated with the use of bicycle-mounted child seats. Lacerations accounted for 1 (17%) of the injuries among those in bicycle trailers and for 2 (5%) of those in bicycle-mounted child seats. Nine children (21%) with injuries related to bicycle-mounted child seat use had fractures.
As far as I know, helmets aren't designed to prevent contusions, abrasions or lacerations.
Perhaps a kid riding a bicyle-mounted seat is better off with a full fac helmet to reduce face injuries and (ideally, but with less certainty and clarity of outcome)mitigate head/brain injury?
Posted by: Evan G | September 23, 2014 at 09:50 AM
A bit OT, but I saw a couple attaching a trailer to a CaBi the other day, which was a first for me. Kid had a helmet. It wouldn't seem to be necessary, but I imagine they wouldn't want to risk looking like bad parents by not using one.
Posted by: DE | September 23, 2014 at 10:03 AM
Don't this suffer from our standard statistical issue in cycling? We don't know the denominator?
Without knowing x miles were ridden with kids in trailers and y miles were ridden with kids on bike seats, are the # of injuries from each really that useful?
I bet the # of annual injuries from unicycling is pretty low but that doesn't mean unicycles are a super-safe mode of transportation.
Posted by: Chris Slatt | September 23, 2014 at 12:00 PM
Anecdote:
Because my name isn't really Smedley Burkhart, I can tell you that I dropped my bike twice on exactly the same tight corner of wet boardwalk, while transporting my baby daughter to daycare in a seat over the rear wheel. She was momentarily unhappy, but uninjured both times and was just as happy to get back on the bike each pm as the day before. My wife said something typical, such as "I guess you know what you're doing," with significantly raised eyebrows. Daughter has since followed a normal developmental trajectory, and is currently a Fulbright scholar, etc., etc,. but who knows what she might have been?
The seat had a sort of roll cage around it, which protected her little arms and she was wearing a helmet. This latter was probably pointless and merely increased her likelihood of c-spine injury, with that big ol' 15 mo. head.
Posted by: Smedley Burkhart | September 23, 2014 at 12:44 PM
@ chris slatt - I agree! we dont have a full data picture here
Posted by: Evan G | September 23, 2014 at 12:46 PM
Another piece of information missing here, I think, is the kind of road/path traveled with the various modes of kid transport. Meaning: trail miles vs urban road miles. My experience is that you are much more likely to see trailers on trails, and bike mounted seats in urban traffic. Just a thought...
Posted by: elizqueenmama | September 23, 2014 at 01:16 PM
the annual injury rate [ related to bicycle-towed child trailers] can be estimated as 0.2 per 100,000 children younger than 5 years.
That is almost unbelievably low.
The average kid under the age of 6 has 0.24 emergency room visits per year. (See http://www.cdc.gov/nchs/data/hus/hus13.pdf#086)
So the overall injury rate for children is about 24,000 per 100,000. So bike trailers account for about 1/120,000 of injuries in children.
Put another way, if the average kid spends more than 1/120,000 of his time in a bike trailer, then the bike trailer is a safer place than where he spends the rest of his life. That's roughly 4 and a half minutes per year. There are roughly 23 million 0-5 year-olds in the US. Numbers on trailers are hard to come by but one estimate I found was 3 million are sold per year. If that's true, then the average trailer would only have to be used for about 45 minutes in its lifetime for riding in a trailer to be safer than living for pre-schoolers.
Posted by: contrarian | September 23, 2014 at 02:59 PM
To be honest, a kid might be safer in a trailer. They're confined, and they have a parent paying attention to their safety. Most of the time, they are at liberty to stick the wet tips of their blankies into electrical outlets and the like, and while there is usually a parent in the vicinity, they may not be paying attention at any given moment.
Posted by: Crickey7 | September 23, 2014 at 03:13 PM
note that in many modern cars kids can stick their fingers into an electric outlet right there in the vehicle.
I've never seen a trailer with an outlet.
QED, trailers are safer.
Posted by: Mike | September 24, 2014 at 08:48 AM