There's been a few times I've driven by a car fire, and even from the opposite side of a divided 4-lane highway, the heat I felt was impressive.
Fire requires fuel, oxygen and ignition (heat). Liquid fuels require external ignition. Batteries do not. But you also have to pump liquid fuels around and generally handle them more to make them do work.
Batteries are more dangerous on a fundamental/conceptual level because they have everything they need to release their energy all at once. So we build them with hard casings for the same reason we build large safety factors into pressurized gas containers so in practice it doesn't really matter.
Batteries and liquid fuels aren't really better or worse than each other from a "much safety or "won't somebody think of the children" point of view. They just require slightly different engineering considerations for an equivalent level of safety.
This is directed just as much (ore maybe even more) at the parent comment as it is at you.
And cars have come along way in the ability to protect the occupants. That same protection measures can be applied to the battery compartment if necessary (steal roll cage, elastic restraint system, air bags). Yes, these things need to be thought about, and yes we do have agencies such as the NTSB and insurance standards that will solve the problem.
Look up the definition of an explosion. I’m super excited about super capacitors - I think they are going to be required in order to make electric cars truly feasible - but the concerns around the safety of them should be dismissed just because they might hold up progress!
I'm dismissing these concerns not because they might hold up progress but because they're well withing what Donald Rumsfeld would call a "known known" of engineering difficulties.
That isn't to say gasoline isn't dangerous. However it isn't quite as dangerous as you seem to think.
Many people will stop only for fuel every 3 hours, and try to get everything they need to do (restroom, buy snacks, eat...) in the amount of time it takes the pump to fill the tank. This isn't a good idea, but it is what people in the real world do.
Gas cars don't have the advantage of being able to charge overnight when you're sleeping, or during the day when you're in meetings or hacking away on something - so in this sense, it's a solid 'pro' for electric vehicles.
It would be pretty easy to setup large scale energy buffers at the equivalent of an electric gas station - from stationary li-ion battery banks, to flywheel energy storage, to supercaps - if spikes were a major issue.
With California (and others) having excess capacity during the day due to Solar, it also allows better arbitrage opportunities, though not clear it would offset the costs.
You have to provision vehicles based off outlier usage (I've used zipcar, normal car rental services, etc. - they are terrible during exactly the times I would need them most, like holidays and months it's good to travel or visit somewhere, and are not reliable), and try to not ruin too badly your 90% pctile usage efficiency while doing so.
If a vehicle is a huge hassle (or impossible) to use for what I'd want to do 5% of the year, I either need a second vehicle for that 5% of the year (even more expensive and maintenance heavy), or a single vehicle that can cover 100% of my usage.
It shouldn't take hours to charge with specialized stations. Sure, the capacitors will give you a charge in minutes, but a supercharger station will give you a charge in about 1-1.5hr. Timing that with bathroom and food breaks should work well.
The capacitor charge stations would need to be more numerous for the decreased mileage. And with the ability to charge at home except for road trips, what makes that model viable?
Edit for sidenote: wilderness areas don't allow motorized vehicles, so maybe that doesn't matter.
Even here in overdeveloped California, the majority of the Sierra Nevada and Northern Coastal range easily counts, as does the ranges in the Mojave.
Federal wilderness designation is an administrative one to apply certain rules to a portion of federally controlled land, not a classification of the remoteness of something or a statement of how untouched it is. Technically the moment you step off Yosemite valley floor you’re in federal wilderness - try to not get distracted by the 1500 tourists staring at you or the 10 giant busses idling in traffic 100 feet away.
The area immediately around the roads are not wilderness in Yosemite, according to their maps.
The charging rate is limited both by the charging controller on the car, and the controller on the charging station. The standards for both of these are developed in consortia that include representatives of utilities and grid operators, so these things get taken into consideration at a very early stage.
> Unless you limit the rate, but then what's the benefit
Yes, as you say, specialized stations that have a buffer between themselves and the grid.
Also, regenerative braking requires storage systems to absorb much higher instant power than plug in charging. If the round trip efficiency of these is better than existing battery tech, that would also improve overall range.
> but then what's the benefit?
Braking and fast charging.
I'm not sure if I believe the above, but it is a good argument.
Over all, I think supercapacitors will be a good option in the future, but not at the current energy density. Especially if they're relying on graphene and the fast charging will essentially require a second one to act as a buffer for the grid.