This road is shared by cars and sheep, although you're much more likely to encounter the latter than the former.
This trail follows the paved and gravel road into the Borgarfjörður valley. It starts by the town's main road as route 946, southbound out of town.
After coming out of town (over the sheep gate), the trail is on a paved road and very gently slopes up. As you pass a hill on your right after the dip the trail turns into a gravel road. As you go further and further into the valley, the views really open up, with the Dyrfjöll mountains coming into view in the west as well as the hidden rhyolite valleys to the east.
This road keeps going after the Mr. Sandman trailhead, passing over the mountains to the deserted inlet Húsavík and the deserted fjord Loðmundarfjörður.