"6 years ago VW included a "growler" on their e-golf, ahead of US requirements.  It provoked discussion on one of the owners groups, first how to shut it up, second if not,  over what noise it should make.  Contenders included an Italian V12 at full song, a chainsaw, air cooled VW engine, a big rig diesel, but the winner of the straw poll - the sound from the 60's cartoon Jetson's flying car"

"Right now, hydrogen is only a thing because it isn't a threat to the oil industry. If it did happen, it would mean new markets for natural gas, to offset any lessening demand for liquid fuels. They are holding it up as a Shiny New Thing, that Will Be Great, and you can buy one Real Soon Now. Just buy one more gasoline burning car, and when it's time to replace that, we will have this wonderful thing for you. Whatever you do, don't buy one of those impractical, and inconvenient battery electric cars, because if you did, a truly horrific thing could occur. Transportation could happen without any way for an oil company to make a profit from it. /sarcasmUnfortunately Hydrogen is a true dead end. Despite its place as the most abundant element in the universe (that we know about),  free hydrogen doesn't exist on the surface of this planet.  You want it, you have to pry it away from a compound.  This will always take more energy than you can get back from the process.Its hard to store,  bulky compared to liquid fuels, and the current best available batteries, and difficult (and inefficient) to generate. Right now hydrogen is a fossil fuel, its made by steam reforming methane, with CO and CO2 as byproducts. Yes, you can generate it by electrolysis of water. It takes 50-55 kWh of electricity to separate a kilogram of hydrogen, compress it to storage pressure, and chill. The previous generation of Mirai would get about 66 miles from that amount of hydrogen. Take that same 50-55 kWh and charge a comparably sized battery electric vehicle with it, and get 200-220 miles from it.The batteries will be smaller (but heavier) than the hydrogen storage, and will be allowed into tunnels and underground parking structures that currently prohibit vehicles transporting it to use them. (this includes propane fueled cars) You also won't have the problem of getting your pressure tank checked regularly. Current tanks store the hydrogen at 650 bar, and are large enough to invoke some jurisdictions laws about pressure vessel certification.Electrical generation on average in the US results in 90 grams of CO2 per mile in an average BEV, well ahead of the current gas powered automotive average of 350 grams per mile. Electric sourced hydrogen will be triple that figure, don't know enough about the steam reforming process to do an accurate calculation for the methane source. (just accounting for the input chemicals, you get about 5kg of CO2 for every kg of hydrogen extracted, but that doesn't account for all the heat you have to add)"