What No One Tells You About Vehicle Weight and Pollution
Episode 300 of SAE Tomorrow Today marks a milestone with a powerful conversation on the hidden costs of going green. Authors Nick Molden and Felix Leach dive into insights from their book Critical Mass, revealing why vehicle weight—not just tailpipe emissions—is the key to understanding environmental impact. As EVs tip the scales at 700 pounds more than combustion cars, they're driving up tire pollution, road wear, and non-exhaust emissions. The duo also propose a bold solution: a weight-based tax system to push the industry toward lighter, truly sustainable vehicles.
Transcript
00:00:00 you recently published a fantastic book that opened my eyes and made me think a lot called critical mass and we're going to get into that today as we go through this conversation. But Felix, I I want to kick things off. You're an expert in this field. What is the one thing we need to know about green cars?
>> Yeah. So, the the one thing we need to
00:00:20 know about green cars is that the weight of a car is the best single measure of its environmental impact per unit of distance driven. It really is that simple. So if that's the case, then why are global OEMs, not just American, why are all these global OEMs can it seems like if you want to use the term bloat, they're getting heavier. They're they're getting bigger. There's a global trend
00:00:39 here.
>> That's right. And I think it's because in part it's what we as consumers demand. I want my car to have the latest features. Uh there's safety aspects as well. The more um kind of crumple zones and other aspects you put into your car, uh the heavier it gets, but the safer it is. So I think there's a number of ways that we as users demand uh these heavier
00:00:58 cars but we're not really taking into proper consideration the consequences of this bloat like you say
>> Nick are one of those major if you want to use the term consequences tire pollutions brakes emissions because the vehicle is heavier it takes more mass to stop it is that one of the the effects
>> oh absolutely and in a way that's the one that is come becoming the the the
00:01:19 really sort of emblematic problem of the shift towards electric vehicles cuz electric vehicles on average are sort of something that's sort of 700 lb heavier than a typical uh combustion vehicle and that's leading to a proportionate increase in in tire pollutants. So just at the moment we think we've cracked the problem of vehicle pollution by chopping off the tailpipe. Actually it turns out
00:01:43 that uh that you've got this significant problem which actually long predates electric vehicles but it's just getting a lot worse with that heavier weight.