It makes for a cute things to do tip but it has its serious side. The cows do have right of way and beware if you hit one when driving - you will have to pay a fine for the damage (about AUD 300) as well as the damage to your rental car. The roads are very winding and hilly so be careful when you go around a tight corner. Keep to the speed limit of 50 kph.
Because everything that isn't grown locally comes by ship there are times when the fruit and veg section of the supermarket is a bit low on stock. The hotels and resorts stock up so are OK and the locals grow most for themselves in the fabulous fertile soil. Look for road side stalls to supplement your fruit and veg
Should you run over one of these animals, you are in the wrong. Even though the animal might have fell off a cliff and landed on your vehicle, you are still in the wrong. Silly you, you should have stayed in bed.
Then comes the bad news, you have to pay. Whoa, not just for the beast but for what it is estimated it would have been worth in the future in terms of breeding, meat etc.. So, you might end up paying for 20 cows even though you only hit one or it hit you.
So, there's a 50kph speed limit all over the island except in town, where it's 40. Dare I suggest you abide by it.
Having said all that, the cows are pretty street smart, unlike their Aussie counterparts.
You have to be carefull. If you want to travel to this Island and you are not from Australia, you have to have a reentry visa. I called the Hungarian Australian Embossy, they told me Norfolk Island is a part of Australia, but when we were there. The officer told me Norfolk Island not a part of Australia, Norfolk is independent. You need reentry visa, because you have to go back to Australia. So we did a new visa on the Island. The officer was very nice too. He helped us. But we had not enough information.
The island have many cows. Don't hit any of them, because you have to pay for. People like cows on the island. They give you milk. You have to be carefull, if you driveing a car.