First of all, in SimCity 3000 it is the Mayor's job to place those nice, fancy on-ramps, off-ramps and highway intersections. They all get made with the same On-Ramp tool.

You can put this tool to work in two different situations. One is in the corners of the intersection between two highways. Poke your on-ramp tool snug in the corner there, and if the tiles turn blue you. re all set to build an interchange. That is, if you. ve been taking care of business and have enough money in the treasury.

The other situation is where a road crosses under a highway. You can't put a ramp on just any stretch of highway. There has to be a road to drive on from, or off to -- otherwise some poor sap of a Sim would drive off the highway into nothing, and I'd have to send out a crew to clean up the mess. Hey, I've got enough to worry about, thank you very much.

The main trick is to point your On-ramp tool a tile or two to the side of the road, right next to the highway. Once again, if it turns blue you're in business.

If it stays red, there are a couple of things to look for. One is uneven terrain. Though my construction crews can make highways go over all sorts of bumpy terrain, for an on-ramp they need at least three flat tiles, at the same elevation as the highway, counting from the spot where the road and the highway intersect. Oh, and if there's anything built on one of those tiles -- a park, say, or a zone with something already built on it? Uh-uh. My teams are under strict instructions not to tear down anyone's property in order to put in road stuff. Only the Mayor can demolish public or private property to make way for highway construction.