While all states now observe the holiday, some did not name the day after King.
Most states now observe the higher speed limit.
Several other states observe maximum thresholds that are lower than the maxima provided by federal law.
Before 1961, the entire state observed central standard time.
Most, but not all, states and most private businesses also observe a Sunday holiday on the following Monday.
In cases where the federation mandates that each state observe the public holiday, it is considered a national holiday.
Yet four states and the majority of the nation's businesses did not observe the holiday at all.
Most states now observe the higher speed limit, which critics contend has led to more accidents.
Each referendum followed a trial period during which the state observed daylight saving time.
"Territorial integrity" requires states to actively observe international human rights standards.