As the American economy continues to surge a very real bottleneck is emerging--the ability of the infrastructure to handle the traffic it generates. And this issue affects much more than weekend travelers. MODERN MARVELSTM visits planning offices and government agencies for an eye-opening look at, literally and figuratively, the road we are on. See how small the margins for error have become--and how disastrous the results can be when problems arise. And as our traffic systems come closer to their capacity, crises are likely to become more frequent.