Car Fire Blanket
Bridgehill recommends stocking their Car Fire Blankets in every tunnel, car park, ferry, and - ahem - electric car charging station out there. And sure, following this recommendation would send a sack of cash Bridgehill's way, but in this case, I think averting the spread of fuel fires and potential explosions is one example of when making a few people rich benefits a whole lot more.
Plus, check out the Car Fire Blanket video, how fast and well this thing sucks the flames' oxygen supply out from under them. Bridgehill says Car Fire Blanketing an affected vehicle will isolate the fire in less than 20 seconds, and safely squelch it when left on for 20 minutes. It not only prevents the spread of the fire, but also heavy smoke and toxic gases, often times the worse offenders in fire emergencies.
Note: for electric cars whose batteries have caught fire, the standard Car Fire Blanket isn't suitable, but Bridgehill also makes a Lithium Blanket that is. However, that one is for professional use only, to be kept in firefighters' and other first responders' vehicles.