This highlights the difference between a law and a social contract. In the case of something like murder or domestic abuse, the law and the social contract are very closely aligned - they are forbidden, and everyone almost universally agrees on these prohibitions.
In the case of something like speed limits, the law and the social contract can be quite far apart. As your linked video illustrates, road design (not the posted speed limit) is the primary factor in determining how fast people drive. A social contract is still in place here, but it's rooted in what people collectively think is safe and acceptable, not what is posted on the speed limit sign. It is not usually socially acceptable to drive significantly faster or more aggressively than the rest of traffic, regardless of whether everyone is already speeding or not. Aggressive driving like interfering with or intimidating other drivers is much less acceptable than a simple speed differential.
People can get pretty riled up when the law doesn't match the social contract:
freerepublic.com
Gord Thompson may be the only man in Ontario ever charged under the Highway Traffic Act for obeying the letter of the law. The teacher from Campbellford and another motorist caused a four-kilometre traffic jam on Highway 401 seven years ago by driving side by side at the posted 100 km/h speed limit. They were charged with obstructing traffic and had their licences temporarily suspended.
Weeks earlier, Thompson had been ticketed for going 117 km/h on the same road and staged his slow-motion protest after a judge told him he was breaking the law by going even a kilometre over the posted limit.
“It still kind of gets my blood going,” Thompson said this week. “The number on the [speed limit] sign isn’t the number you’re expected to drive at and no one will tell you what the tolerance actually is.” Thompson’s situation may be the most ludicrous application of Ontario’s speeding laws but it puts into focus what motorists prove with their right feet – that 100 km/h is often too slow for the province’s 400-series highways. A recent study by University of Toronto researcher Baher Abdulhai found every single driver exceeding the speed limit on some stretches of highway that he and graduate student Jaime Abraham studied. His study recommended that the speed limit be raised to a more realistic 130 km/h.
The best road design elements shift the context of the social contract to include more people. In Ontario every piece of pavement is effectively a
road, with the implied context that
this is a place exclusively for automobiles, and therefore that the appropriate social contract is the one used between vehicles. If a pedestrian or cyclist happens to be on the pavement, the common reaction of drivers is to say "get the hell out of the road", rather than adjusting the social contract to include them. The video on 'stroads' from the same channel is also worth watching: