1. Existing service station equipment is less than 5 minutes for a 20 gallon equivalent tank.
2. We have had Compressed Natural Gas vehicles on the road for decades. While not great in numbers, they have certainly been involved in accidents. The basic design requirement of needing to withstand the 3,600 psi pressure makes them rather sturdy in the first place. The rock-stuff is not very practical; it greatly increases the storage volume or greatly reduces the already lesser range.
Since Honda has been selling CNG powered Civics since 1998 along with others since then, those issues are fully resolved. The main problem now is the refueling infrastructure. Past sales were limited to places like California and Oklahoma where commercial CNG refueling was available. Now that is growing to more locations so vehicle sales are growing, slowly, but growing.
We switched to NATGAS...on the Freeways...when we could. Sometimes...it was dicey. And we would end up on the shoulder for a period of time. Ha!!
Point being....NATGAS powered vehicle's have been around for a long time.