Should states or regions of a country standardize their laws?

[robocpf1]

I would appreciate input from people in other countries that have large or politically powerful states or regions (Quebec in Canada, for instance, or the Basque in Spain).

In the US, we have a dual government system of both Federal laws (that affect everyone in the country) and State laws (that only affect people in that particular State). Both federal and state governments also have different political structure and power, but that's not what I want to get into right now.

Specific to the question at hand, you can have two completely different sets of laws between two different states. If you get pulled over for driving too fast in North Carolina, for instance, how fast you were driving determines what kind of offense it is. Just a few mph over the limit is an infraction, but if you reach...I think 15? mph over the limit, the offense becomes a serious felony.

However, in other states, for a simple speeding violation it doesn't matter how fast you were going at all - every iteration is still only an infraction, just a minor blemish on your record and not very serious.

So my question is, for the US (and I guess for any other country that utilizes this dual system) should we have some sort of Standardization between the states' different laws? Are there really things that, between different states, should be considered a grand crime in one state but not at all illegal in the next?