Can an Electronic Message Board Be Used as a Campaign Sign in Maine?

We've all seen the campaign signs cropping up like weeds at election time each year. Every intersection seems to have them littered all over the side of the road, trying to get your attention to vote for particular candidates.

These signs are usually pretty small, and about the size of most home "For Sale" signs on front lawns. But this seemed really weird and unfair to me when I was driving with my son last week.

At the intersection of Lisbon and Pleasant Street were a bunch of political signs and a giant electronic message sign that dwarfed them all.

It made me wonder if this is even legal. It's not the only one I saw in the city either.

I know that the campaigns with the most money to spend get more ad time on TV and radio, and I guess the same goes for the size of your sign. This definitely gets people's attention, but the message will be missed on green lights as the sign tries to cycle through each message. There were several candidates and issues the sign was cycling through.

I did a little digging to see if I could find laws that prohibit a sign this large, and looked specifically for laws in the city of Lewiston. This is what I found:

5. Political signs. Signs of a temporary nature bearing political messages relating to an election, primary or referendum may be placed within or outside the public right-of-way of any street or highway in accordance with the timelines established in M.R.S.A. Title 23, §1913-A, Section 1(H). Political signs located within or outside the public right-of-way of any street or highway are prohibited on or in front of City owned property including schools, parks, cemeteries, and municipally owned buildings. Notwithstanding Article V. Sec. 7, the code enforcement official may remove any political signs erected contrary to this section.

It also appears that this might be private land the sign is on. If so, I guess it's perfectly legal. What do you think?