Moose are NOT nocturnal.
More Info: Moose are not active at night or nocturnal but are crepuscular, meaning that they are most active at dawn or dusk. Moose rest during the night hours. Moose have eyesight that is worse than a human's, but possess better senses of smell and hearing.
Advantages of Being Crepuscular
There is an evolutionary advantage to being crepuscular. Dusk and dawn are twilight times, so that it just light enough for the moose to get around but too dark for predators to easily see. Some animals see best at twilight than they are at what we human would consider normal light levels. For example, anole lizards can only see certain colors in twilight.
It is unknown if the moose can see better in twilight than in bright sunshine. Dawn and dusk tend to be cooler parts of the day. During hot weather, moose move out to find a body of water to cool off in or they will suffer from the heat.
Warnings to Motorists
Because moose are most active at dawn and dusk, motorists need to be especially careful of hitting a moose at these times. Drive slowly in areas known to have moose, even driving below the speed limit if necessary.
Also drive slowly during the spring and the autumn. In the spring, young moose away from their mothers for the first time tend to blunder into oncoming traffic. In the autumn, adult moose are distracted by the rutting season to notice moving vehicles.