Things you should expect to see on the highway include people texting and driving, dead animals, and Finnish F-18s landing and taking off.
Well, that last one may be only true in the Finland. While it's a myth that the Interstate Highway System in America requires one straight mile for every five miles of road, many military aircraft are perfectly capable of landing and taking off from civilian highways. Finland practices this capability to ensure they can disperse their fighters if necessary during a conflict.
And as you can see in the above GIF from a similar exercise, the fighters don't need anywhere near a mile of road. The minimum takeoff distance for an F-18C on a flat surface is 1,700 feet, about 0.33 miles. The Finnish F-18 taking off in the video is using a downhill slope, letting it gather speed a little more quickly and get off the road.
The whole video from the Finnish Defence Forces is fun, but skip to 0:18 if you only want to watch the jets.