Why does Milwaukee have to spend money replacing eighty percent of its street signs? It turns out its not a simple matter of dictation by some federal bureaucrat in Washington. It is a matter of state law.
Bob Bryson, Chief Traffic and Street Lighting Engineer for City of Milwaukee Department of Public Works, is an old fashioned, straight-talking, civil servant, who is happy to give informative responses to citizen inquiries. After a quick look at the state statutes (the ones he has to know to do his job), he identified Wis. Stats. 349.065, Uniform Traffic Control as the relevant law. This statute makes changes in the Manual on Uniform Traffic Control Devices for Streets and Highways mandatory for all city streets.
So, although the Manual itself is only advisory, when the manual was revised, Wis. Stats. 349.065 made the changes mandatory for all cities. Why is that in the Wisconsin legal code? Bryson doesn’t have the complete history, but state laws like that are often the result of federal funding requirements.
There are many things congress does not have direct constitutional authority to regulate, which it can influence by withholding federal funding. Since the federal income tax is the largest pot of money in American government, that can be a powerful tool.
For example, when all the states reduced their maximum speed limits to 55 miles per hour in the 1970s, that was because congress provided that no state with a higher speed limit could receive federal highway funds. States returned to 65 mph limits on freeways, and in some states even 70 mph, after congress decided they could do so, and still receive federal highway funds.
Congress can’t set speed limits in the states. It can only cut off highway funding to those states which don’t conform their laws to national policy. By some such indirect process, once the Federal Highway Administration published a Final Rule, “State Manuals must be in substantial conformance with the National MUTCD within two years as specified in 23 CFR 655.603(a).” CFR is the Code of Federal Regulations.
Why does the manual require street signs to be upper and lower case letters, instead of all capitals like we have now? The stated purpose is to make street signs more readable, for the speed drivers are moving at. A lot of people find all caps makes for a more readable sign from a greater distance while driving. Bryson personally agrees, but reports that a number of studies relied on, in updating the Manual, found drivers could read upper and lower case street names more easily.
Of course it is helpful to interstate drivers that stop signs look the same in every state, and all states have a common green-and-white sign system on freeways. Some standardization does “promote the general welfare” without making “the blessings of liberty” less secure. Arguably, dictating the type of lettering on the street signs of individual cities is over-reach. Maybe big green highway signs are more readable with a mix of capital and small letters. Maybe a study of city corner street signs would come up with a different result.