Safe Streets, Livable Streets

Abstract

Transportation safety is a highly contentious issue in the design of cities and communities. While urban designers, architects, and planners often encourage the use of aesthetic streetscape treatments to enhance the liability of urban streets, conventional transportation safety practice regards roadside features such as street trees as fixed-object hazards and strongly discourages their use. In this study, I examine the subject of livable streetscape treatments and find compelling evidence that suggests they may actually enhance the safety of urban roadways. Concerns about their safety effects do not appear to be founded on empirical observations of crash performance, but instead on a design philosophy that discounts the important relationship between driver behavior and safety. This study traces the origin and evolution of this philosophy, and proposes an alternative that may better account for the dynamic relationships between road design, driver behavior, and transportation safety.

It has taken many decades for roadway designers to begin to recognize that how road and road environments are designed affects safety, and to identify what particular features enhance or detract from safety in a given environment. This process is still evolving. Historically, there has been a tendency for those funding research to focus on rural or high-speed environments, and on pavements and structures. One outcome of the resulting underemphasis on safety and urban design concerns, as author Eric Dumbaugh identified in this article, is the problem with the published research about urban roadside design in the U.S.: it is limited in both scope and quantity. With these limitations, it is understandable that city street designers extrapolate from principles learned in a rural highway environment. They may not be standing on the firmest ground when they do this, but they judge that it is the best ground they have.