Today’s topic: What to do with Japanglish?

マナーアップ？

An anecdote from several years ago. During the Spring Traffic Safety Campaign here in Sendai (仙台), many signboards were erected here and there along the roads to remind the drivers of safe driving. That was OK, for sure, but the thing is, the phrase on the boards regrettably appeared to be quasi-English or Japanglish.
It said:
「マナーアップ　ザ宮城　ー宮城県警」
Although the Japanese itself was, in a sense, rhythmical and catchy as it was, I wondered what an English equivalent would be. So, to begin with, I tried breaking it down into several factors:

First, ‘the’ is superfluous (「宮城」is a proper name).
Second, the portion「ザ宮城　ー宮城県警」is perhaps not necessary in the first place: because
(a) the mention of the authorities is redundant information in such a context as this, and
(b) in light of the ‘brevity requirement’ imposed on roadway signs, ‘the more extended the phrase, the more danger it may cause.’
Third,「マナーアップ」does not seem to be proper English.

But back then, the last problem appeared a bit tough for me to solve.

My tentative solution was the following:

“DRIVE COURTEOUSLY”

But I’m still not sure this might be a neat and happy solution. Could you spare time to help me out with this, buddies? Should I drop the idea? Is there a more appropriate expression?

Thank you in advance :).