As I've seen mentioned here already, moose at night are very very dangerous, and accidents with them range from minor bumps where moose actually run into the vehicles(I've actually witnessed this), to full collisions where the animal can smash a windsheild, and its legs trash around inside a vehicle. No, you will not have time to react, as many moose sprint onto the road. Many people have been seriously injured this way. Another animal that you have to be aware of while driving(In particularly, the Northern Penninsula), is the caribou, which is not so big as a moose, but can pack quite a punch. These guys are not afraid of passing vehicles and sometimes, make a dash across highways, day or night. The daytime driving is not so much a problem, but please, while driving at night, don't even drive the speed limit, or you may have a unwanted wildlife encounter.
Newfoundland is full of big Moose - 127,000 of them at last count. You will see the occasional one along the highway through the daytime but they are out in force at night - on the highways too. They are dark (hard to see) and heavy when they fall onto your windshield and crush it. Gros Morne has a sign with the latest statistics for the year (13 moose and 7 caribou accidents so far that year in the park). Do not drive around at night if you have any sense (PS - I hit one in Maine on Interstate-95 so I know what they can do)!