Around here, almost everything besides residential streets is 45 mph. There are a few streets that are 30-35-40 mph, but if you want to actually get anywhere, you have to take the 45 mph streets. My '07 Met topped out at 38 mph. It is common here for everybody to go 50-55 on 45 mph roads, and when the light changes, they just have to see how fast they can reach that speed. If you are in front of them on a Met, you're in trouble. Once they see how slow you are, then they just get mad and start blowing their horns. The real danger is before they know. They expect you to take off like a rocket, and will run over you before you even get across the intersection. There have been many scooter accidents here because of that. Even with the 4 way flashers I never felt safe enough to ride it in town. Much safer out on 65 mph rural roads where you can ride on the shoulder. My Zuma 125 keeps up fairly well on 45 mph roads when they are flat. Slight hills got it down to 40 mph, but I weigh 220. It can be ridden on 65 mph roads, as long as you stay to the far right, and move over if a car comes up behind you and there is oncoming traffic. A 50cc Met can be ridden from coast to coast if you are determined enough, and plot your course well. Now that is what I would call and adventure ride, and it would not cost a fortune to do it either.
2002 Vulcan 750, 2013 Royal Enfield B5
2001 XT225, 2009 Genuine Stella
2012 Zuma 125, 1980 Puch moped