Effects and Controversy

Rush hour on I-45, downtown Houston.

Freeways have been constructed both between urban centres and within them, making common the style of sprawling suburban development found near most modern cities. As well as reducing travel times, the ease of driving on them reduces accident rates, though the speeds involved also tend to increase the severity and death rate of the collisions that do still happen.

Freeways have been heavily criticized by environmentalists and preservationists for the noise, pollution, and economic shifts they bring. Additionally, they have also been criticized by the driving public for the inefficiency with which they handle peak hour traffic.

Often, rural freeways open up vast areas to economic development, generally raising property values. But mature freeways in urban areas are quite often a source of lowered property values, contributing to the deleterious effects of urban blight. One major problem is that even with overpasses and underpasses, freeways tend to divide neighborhoods — especially impoverished ones where residents are less likely to own a car that could easily take them around the freeway. For these reasons, almost no new urban freeways have been built in the U.S. since 1970.

Some have even been demolished and reclaimed as boulevards, notably in Portland (Harbor Drive), San Francisco (Embarcadero Freeway) and Milwaukee (Park East Freeway). Growing anti-urban freeway sentiment has resulted in some significant policy changes; the most noteworthy was an FHWA case study involving the West Side Highway in Manhattan, a quintessential urban freeway in need of expansion and reconstruction. The outcome of the study basically concluded that the current elevated highway should be replaced with a new, at-grade boulevard with integrated pedestrian facilities. This case study may be a precedent for areas where a typical, elevated urban freeway is not desirable and/or may not be effective at handling impacted traffic. In Boston, Massachusetts, the elevated Central Artery, originally built in the 1950s, was demolished in 2005 when new tunnels were built for an expanded Central Artery directly beneath the pre-existing elevated highway. Completion of the project, referred to as the Big Dig allowed Boston to reunite its business district with the waterfront, severed by the original elevated Central Artery, while maintaining the expressway through downtown, now located underground.

Freeway opponents argue that freeway expansion is self-defeating, in that expansion will just generate more traffic. That is, even if traffic congestion is initially shifted from local streets to a new or widened freeway, people will begin to run errands and commutes to more remote locations which took too long to reach in the past. Over time, the freeway and its environs will become congested again as both the average number and distance of trips increase.

Freeway advocates argue that properly designed and maintained freeways are aesthetically pleasing, convenient, and safe, at least in comparison to the uncontrolled roads they replace or supplement, and that they expand recreation, employment and education opportunities for individuals and open new markets to small businesses. And for many, uncongested freeways are fun to drive.

At present, freeway expansion has largely stalled in the United States, due to a multitude of factors that converged in the 1970s: higher due process requirements prior to taking of private property, increasing land values, increasing costs for construction materials, local opposition to new freeways in urban cores, the passage of the National Environmental Policy Act which imposed the requirement that each new project must have an environmental impact statement or report.