Helmets for electric bikes and other light powered vehicles
Summary: If you use a bicycle helmet for a powered vehicle traveling 20 mph (32 kph) or more, you are taking a greater risk than most unpowered bicyclists that the helmet will not be adequate for the type of crash you should expect. For reasons explained below we recommend a light motorcycle helmet or at least a helmet meeting the Dutch NTA 8776 ebike helmet standard. For low speed powered scooters, CPSC recommends a bicycle helmet. See this page for ebike helmet laws.
The popularity of electric bicycles and those powered by small gas engines has been growing in the US after years of popularity in Europe. A number of states have passed laws since 2015 setting up three categories of ebikes and providing regulations for where they can be operated. Some states require helmets
for some or all three ebike categories. The categories are not useful for choosing a helmet, since the severity of a crash may differ but for any powered bicycle it is likely to be worse than a pedal cycle crash. Not many riders pedal as fast as they ride on an ebike, so the speed will probably be higher. And we seem to notice a tendency for ebike riders on trails to maintain their speed in situations where pedaled bike riders are likely to ease off.
What helmet do you need for one of those vehicles? Some light powered vehicles are no faster than a bicycle, leading to speculation that any bicycle helmet could be adequate. We would not recommend that for several reasons:
- This type of powered vehicle will normally be operating near its maximum speed if on a street or highway. Although some bicyclists can match that speed, most can not, and none can on uphills. The real world average bicycle speed is about half what an ebike normally attains, so pedal cyclists would be less likely to be traveling at the maximum when a crash occurs. The critical measure is the closing speed with pavement, but with high forward speed there is a higher probability that the average powered vehicle impact would be more severe.
- In a head-on crash with another bike, pedestrian or ebike the severity of impact will probably be considerably higher than a pedal cycle crash because it is likely that ebike speed will be higher. In addition the electric vehicle will probably be heavier than a pedaled bike.
- In addition to shared-use trails, ebikes are used on streets and roads, and mix with heavier motor vehicles such as cars and trucks. Bicycles do that too, but are usually off to the side if the motorized traffic is fast, and in most situations they have a different way of interacting with other vehicles.
- Bicycle helmets are tested at about 14 mph, corresponding to the closing speed with the pavement when a rider falls. There is a vector energy component from forward speed, but it is not significant as long as the helmet slides on the pavement. Ebikes and motorcycles have higher forward speed, and are more likely to suffer greater impacts.
- The user of a powered vehicle is cooled by the passing airstream but not generating as much heat as a pedal cyclist with pedaling effort. Fewer compromises are necessary with heat and weight to produce a comfortable helmet. The rider of a motorbike may freeze in the winter while a cyclist is toasty warm. In the summer the cyclist suffers much more from the heat, and most riders who ride hard cannot tolerate a helmet without substantial vents.
- Standard bicycle helmets do not protect the face (you can live just fine with a broken nose, lost teeth or a split lip from a bicycle crash) or the jaw joint, a pathway to transmit injurious force to the brain in a crash at motorized speeds. Although some downhill bicycle racing helmets do have a front chinbar, it is seldom padded adequately for impact protection.
- Helmets for these vehicles may be used at speeds well above the design speed. Modifying small gas motors for higher output has been an art form in some communities. It can be sufficient just to remove or bypass a governor mechanism to run the machine at 35 or 40 mph. And for gas models, some of the "49 cc" motors turn out to be considerably larger than that when actually measured, with more power than would be expected. An electric bike fitted with larger diameter wheels and tires may be considerably faster than its normal limit. And design speeds on unmodified ebikes already top out at 28 mph.
These factors would normally lead us to recommend a light motorcycle helmet for motorbikes or the 28mph electric vehicles. Helmets meeting the DOT motorcycle standard, while much too heavy to be optimum, should be adequate. Or you can opt for one of the helmets now meeting the Dutch ebike helmet standard, described below. Another option might be a helmet meeting the downhill mountain bike racing standard, although those are not certified for a powered vehicle.
Laws require helmets for ebike riders in some states. Here is a list of ebike helmet laws.
The first study we have seen of ebike head injuries included 20 riders and pedestrians, all under 18. Seventeen of them had head injuries. None had been wearing a helmet. One died.
Powered scooters are a different class of vehicle. They are not as fast as ebikes, motorbikes and motorscooters because they are not stable enough to travel that fast! The Consumer Product Safety Commission has issued an advisory recommending the use of bicycle helmets for riding powered scooters, along with knee and elbow pads. In 2006 they issued another recommendation
that bicycle helmets are fine for low powered motorized scooters.
There is no US government standard for light powered vehicles other than the DOT motorcycle helmet standard, required by law for any motorcycle helmet. ASTM has adopted an alternative motorcycle helmet standard -- F3103-14 -- to produce more user-friendly helmets for off-road use designed for the most frequent impacts.
The Snell Foundation, a respected name in helmet standards-setting, published a standard for use with low powered vehicles, mopeds, and motorized bicycles in 1998. Reflecting the higher speeds expected, it has lab test drops somewhat higher than bicycle helmet standards at 2.4 meters on the flat anvil and 1.6 meters on anvils of other shapes. The extent of protection is considerably greater than a bicycle helmet standard. It is referred to as Snell L-98. As of September, 2015, 17 years after it was adopted, there were no helmets certified to it listed on the Snell website, but you can check this page on the Snell site to see if that has changed.
In 2016 the Netherlands published an ebike helmet standard, designated as NTA 8776. The test line in the front is only 2.5mm lower than the CPSC bicycle helmet standard, but on the sides and rear it is much lower. The flat anvil test drop is just above the CPSC standard, and the two are probably about equally stringent given that the Dutch standard uses the less severe European drop rig. Snell's B-95 standard would be tougher. On the curbstone anvil the Dutch are tougher, but they do not test with the hemispheric anvil at all. There are helmets available now from several manufacturers that meet the standard. You can check for the latest on the Holland Bike Shop site. Brands include Abus, Agu, Giro, Lazer and Polisport. Not all of them meet the Dutch standard, but you can check by doing a site search on NTA 8776. Our last check showed that at least one model from Abus, Agu, Giro, Limar and Polisport met the standard.
There are now many more helmets meeting the Dutch ebike standard on our Helmets for the current year page. You can find them with a search in the page for Dutch. But keep in mind that those have much less protection than a motorcycle helmet meeting the US DOT standard. Even so, the absence of any other ebike-specific standard has made NTA 8776 the ebike helmets standard in the market.
In the US we have at least two bike helmet standards that exceed the normal CPSC/ASTM bike helmet standard. There is the ASTM F1952 Downhill Mountain Bike Racing standard and F2032 for BMX cycling. Helmets meeting either one come close to the Dutch standard, and some do meet it. Giro is now advertising two models as certified to the Dutch ebike standard.
The US DOT motorcycle standard exceeds the Dutch ebike standard in coverage and impact testing, readily seen in the difference between the helmets designed to each. We have two charts comparing the lab test lines (tested coverage) and impact velocities.
A bike helmet provides some protection in any crash, but not enough for a powered vehicle consistently traveling at 20 mph and higher. You are taking a greater risk than a pedal cyclist that the helmet will not be adequate for the type of crash you should expect. For a 28MPH ebike it would probably make sense to consider a light motorcycle helmet. There are lots of them to choose from at your local motorcycle dealer, or you can find them on the web. At a minimum your helmet should be certified to the Dutch NTA 8776 standard, the only one specifically for ebikes.