In the case of speeding it is well known that higher speeds leads to more traffic deaths so we can easily calculate the death toll of people going 85 instead of 55 and implement appropriate measures to reduce that.
Just because everyone ignores or despises a law, it doesn't necessarily make it unjust or wrong.
Even with many young men, you are not cool, not a rebel, not “boys will be boys”, not “just this once”, none of that “I live nearby”. You are a bloody idiot, mate, and a wanker.
But there is a very practical point that if the "governed" are not listening, than the "governor" had better! Revolutions and civil wars have occurred over such.
Also too often "popular" is conflated with "visible/noisome support". See the gay marriage here in Australia. Lots of noise on both sides, it took a referendum to prove that 61% supported it.
Aside: my experience is it has been socially unacceptable to drink drive for 25+ years for everyone I know. You and I are having different life experiences!
Hope yours is a good one, cheers!
Things aren't always so simple when second level effects are accounted for.
Several reports point out that when the 55 speed limit was repealed, traffic deaths increased. Here are a couple of citations:
1) "Rising speed limits over the past 25 years have cost nearly 37,000 lives, including more than 1,900 in 2017 alone, a new study by the Insurance Institute for Highway Safety shows ... For the new study, Charles Farmer, IIHS vice president for research and statistical services, analyzed the effect of changes in the maximum posted speed limit in every state from 1993 to 2017. ... Farmer found that a 5 mph increase in the maximum speed limit was associated with an 8 percent increase in the fatality rate on interstates and freeways " - https://www.iihs.org/news/detail/speed-limit-increases-are-t...
2) "Long-Term Effects of Repealing the National Maximum Speed Limit in the United States" - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2724439/
> We examined the long-term effects of the 1995 repeal of federal speed limit controls on road fatalities and injuries in fatal crashes. ... We found a 3.2% increase in road fatalities attributable to the raised speed limits on all road types in the United States. The highest increases were on rural interstates (9.1%) and urban interstates (4.0%). We estimated that 12 545 deaths (95% confidence interval [CI] = 8739, 16 352) and 36 583 injuries in fatal crashes (95% CI = 29 322, 43 844) were attributable to increases in speed limits across the United States."
But that's after it was repealed.
Going back to when the law was put into place, https://en.wikipedia.org/wiki/National_Maximum_Speed_Law#Saf... states "The limit's effect on highway safety is unclear."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5005740/ shows "Joinpoint analysis of trends in motor vehicle traffic fatality rates, all ages, by sex, 1968 to 2010" in figure 2 you can see the decrease in fatalities after the law was put into place in 1973, followed by a regression to a decreasing mean.
This is in agreement with Wikipedia's statement "Although the vast majority of states reported fewer traffic deaths in 1974 compared with 1973, there were in fact three states where traffic deaths actually increased ... According to the National Research Council, there was a decrease in fatalities of about 3,000 to 5,000 lives in 1974, and about 2,000 to 4,000 lives saved annually thereafter through 1983".
It therefore doesn't appear that traffic deaths increased with the enactment of the National Maximum Speed Law.
People ignore the sign if the sign doesn't match the road design.
Roads designed for 30, 55 and 85 miles are completely different beasts with different lane width, straight segments length, turn radius, traffic calming elements, etc.
Puting an autobahn and plunking a 50 mph limit there is a recipe for all-out "speeding."