Werner's Blog — Opinion, Analysis, Commentary
Are electric vehicles safer than their gasoline cousins?
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The 2020s will bring about a revolution in mobility: an accelerating transition to e-mobility. The environmental gains will be hugely important in reducing greenhouse gas emissions, as the transportation section is a major contributor. With the transition to e-mobility also comes the question whether electric vehicles (EVs) will be safer or less safe than their internal combustion engine (ICE) cousins. What do we know so far about the safety of EVs?

There are two different ways to assess overall vehicle safety. One is to simulate accidents and measure outcomes in a laboratory setting—you have seen videos with crash-test dummies. The other method involves accident statistics and insurance claim statistics. The latter method is ultimately the more insightful because it shows how safe vehicles are in actual use. However, insurance claim statistics combine multiple effects and it is not easy to disaggregate the compound effect into its separate components. What are the components that determine how well a vehicle fares in actual use?

‘Today's safety record of EVs is influenced by technical factors as well as ownership demographics.’

First, of course, is the structural or technical safety. How well is a car built to withstand a collision, how well is it equipped to protect its passengers, how is it designed to avoid or mitigate collisions. Vehicles contain active and passive safety features that are typically assessed in laboratory settings. Second is where and how vehicles are used, separate from the issue who is driving the vehicle. The driving environment matters as vehicles driven in the city have different accident rates than vehicles driven in rural areas because of traffic density and vehicle speeds. Third is effect of driver selection: cautious drivers may prefer safer cars, while risky drivers may prefer cars that trade off safety for other performance characteristics. In other words, there is a strong self-selection effect. I tend to call it the Volvo effect: the Swedish-made cars have a reputation for being sturdy an feature cutting-edge safety technology, and thus drivers who value safety are more likely to drive Volvos, which in turn lowers accident rates for this type of vehicle. The demographics of Volvo owners reflects this. You are more likely to find moms and dads driving Volvos than fun-seeking twenty-year olds, who if they can afford it may be more likely found driving a Lamborghini (we see many of these in Vancouver). These different effects change over time. The early adopters of electric vehicles may have common demographic features—they may be more affluent than the average driver. This in turn relates to the fourth issue: today's EVs tend to be more expensive than the average vehicle and thus there is a relative price effect. The higher cost of EVs in turn can contribute to higher claims and insurance cost, while more expensive cars may also exhibit more and better safety features. How much the owner of an EV will pay for vehicle insurance thus depends on these interactions of driver selection, driving environment, vehicle safety characteristics, and vehicle repair & replacement cost.

On a technical level, electric vehicles have the potential of being safer than their ICE cousins in the short term. EVs tend to be somewhat heavier than equivalent ICE vehicles because of the extra weight of the batteries, which in turn provides a safety advantage in a collision due to differential weights that benefit the vehicle with the larger weight. This advantage will erode over time as the share of EVs increases. This benefit is transitory, not permanent. However, EVs have intrinsic technical benefits that work to its advantage. The absence of an engine in the front improves the crumple zone, and the placement of batteries at the bottom and center of the vehicle reduces rollover risk (which is a particularly deadly risk). Overall, the lower center of gravity of EVs benefits dynamic stability and breaking.

What about the risk from batteries? The current lithium-ion generation of batteries poses a fire risk, but this risk is eclipsed by the much higher fire risk of ICE vehicles with a tank full of gasoline. Battery technology is improving and EVs will soon run on solid state batteries (as I argued in my November 2018 blog). There have been highly publicized EV incidents involving fire, such as Tesla goes up in flames in video captured by actor Mary McCormack or Life, death, and spontaneous combustion. Yet, vehicle fires in EVs are rare, and these incidents are not always related to accidents but other causes. Importantly, studies have not found any cases of electric shock in EV accidents.

‘Existing regulation prevents EVs from being “too quiet”.’

There is a more insidious risk from EVs: they are much quieter than their ICE cousins. Vehicle noise is a major irritant in urban areas, and overall a quieter city scape is to be welcomed. No more annoying muffler noise. While vehicles are required to be manufactured to emit at most 83 dB(A), some owners modify their mufflers to make them purposefully louder even though the Highway Traffic Act S.75(4) requires "that a driver of any motor vehicle shall not at any time cause the motor vehicle to make any unnecessary noise." Clearly, numerous ICE motorists ignore this. Yet, the quietude of EVs may fail to alert people to the danger of an approaching vehicle. To counteract this risk, the U.S. Highway Safety Administration issued a ruling in February 2018 that vehicles traveling less than 30 km/h must emit warning sounds. The European Union has a requirement for acoustic vehicle alerting systems (AVAS) so that all vehicles emit a noise level of at least 56 db(A) when traveling less than 20 km/h. Arguably, the adverse effect of quiet vehicles may be a transitory phenomenon. People are used to hearing cars because this is what we experience in today's traffic dominated by ICE vehicles. If all vehicles were electric and all quiet, pedestrians would rely more on their eyes than their ears when crossing traffic. Nevertheless, sound is a helpful safety feature for now, and AVAS remains an important and necessary safety feature.

Several countries assign safety ratings to vehicles that enter the market. For example, the U.S. National Highway Traffic Safety Administration (NHTSA) has developed a 1–5 star rating system based on a theoretical Vehicle Safety Score (VSS) that captures the risk of injury to occupants, where a VSS value of 1 is the baseline risk. Four and five star ratings mean better than the baseline, and three or less stars indicate higher levels of risk. The Insurance Institute for Highway Safety (IIHS) provides similar types of ratings. EVs tend to receive better scores than their ICE cousins, but this may in part be due to the fact that many EVs are in the luxury part of the vehicle spectrum. Still, the Chevrolet Volt received a five-star rating as did the luxury-level Tesla 3.

So when you go and buy an electric vehicle, you will likely benefit from novel features common to many other ICE vehicles too. Newer vintages of vehicles have better safety features. EVs do not compromise on safety and in fact exhibit best-in-class safety ratings.

‘Even though EVs tend to have a safety edge over gas-powered cars today, some of this advantage will erode as EVs gain a larger fleet share and attract a broader set of drivers.’

In the long run, will we see fleet-wide benefits in safety? It is unlikely that EVs make drivers better drivers. EVs may have a slight long-term benefit because of design characteristics, but they may also entice drivers to exploit superior acceleration. Thus the benefit from EVs will probably come from better or more advanced software: less human error, or putting a technical lid on human inattention, carelessness, or even recklessness. The weak link in vehicle safety remains the vehicles' all-too-human operators. To make our roads safer, EVs alone won't provide the answer. We need better traffic safety management, including enforcing our traffic laws better.

Further readings and information sources:

Posted on Thursday, July 2, 2020 at 10:20 — #Transportation | #Innovation
© 2020  Prof. Werner Antweiler, University of British Columbia.
[Sauder School of Business] [The University of British Columbia]