If they plummet into the river you know you need to go back to the drawing board. When test vehicles pass over your bridge and make it safely across you know you've succeeded. In the Bridge Construction Set you design and build bridges and then stress test them to see how your creations hold up under pressure.
In The Bridge Construction Set, Building a bridge that doesn't break is what its all about, although watching your bridge creation break and plunge a train into the watery depths below can be half the fun.
