I dont get why you guys are discussing the possiblity of a hydrogen burn/explosion. This would only happen if the hydrogen is stored, and then only if it gets stored in large amounts. At the infinitessimal amounts that appears to be released during this process, it makes no sense to even try to store it beyond what makes for an efficient amount to bother igniting it. Storing hydrogen is impractical at best, and as hydrogen has the smallest possible atomic structure, it can pretty much escape any container, so noone stores hydrogen beyond what they need for immediate use anyway.
So obviously, the hydrogen needs to be used (almost) immediately, and very little if any amount stored. Presumably it would be burned to produce electricity for lights, or during winter for heating the highways, Both of which would produce safer, greener highways. Or during summer and daylight, being transmitted directly into the electric grid, similar to power from water/windmills, wavemachines or solar cells.