ARTERIAL TRAFFIC CALMING-IS IT AN OXYMORON?

For decades, transportation professionals have worked to improve the safety and efficiency of our roadways. Some of the most intense study, emphasis, and success has been on our freeway systems. Through steps such as removing roadside obstacles, providing wider lanes, and managing access, accidents have been consistently reduced and capacity increased. Over time some of these principles have been applied to other street types, including arterial, collector and local streets, at times with mixed results. Street capacity may be increased, but often at a loss of access, neighborhood livability, and pedestrian and bicycle mobility. Streets that were once lined with large trees, parked cars, and full of pedestrian activity have given way to wide, inhospitable expanses of pavement, with few pedestrians and cyclists. In some cases, the application of freeway-type design principles has actually increased speeding and accidents. Thus, it’s no surprise that traffic calming is a recurring item on city council agendas and the topic of discussion in hundreds of neighborhoods across America. Most traffic calming efforts have been applied to local streets through liberal application of speed humps, circles, and various other devices. Often at the forefront of opposition are emergency service providers who are concerned about the proliferation of traffic calming devices and the impact on emergency response times. Now the pressure is on to address higher order streets such as collector and arterial roadways. Facilities, that by definition, are intended to carry the bulk of traffic. Ultimately the discussion of traffic calming can pit neighborhood desires for livability and traffic safety against the objectives of the fire department. Each side having legitimate concerns but often unable to find middle ground. In an effort to understand and quantify the relationship between traffic calming devices and