Pedestrian Safety Guide and Countermeasure Selection System
Example of a well-designed right-turn slip lane with a refuge islands that forces pedestrians to face on-coming traffic, and marked crosswalks. Source: Living Streets (Dan Burden)
Raised medians are curbed sections that typically occupy the center of a roadway. They can facilitate pedestrian crossings by providing a crossing area that is physically separated from the automobile path of travel, reducing pedestrian crossing distances, and enabling pedestrians to focus on one direction of traffic at a time when crossing the street. Raised medians can be especially helpful for pedestrians who are unable to judge distances accurately or who have difficulty completing wide roadway crossings. They can also improve the visibility of crossing pedestrians to motorists by putting them in middle of the roadway and providing space for lighting to illuminate the crossing.
Trees and other landscaping elements can be added to raised medians as long as they do not restrict visibility. These elements can help change the character of a street and reduce speeds. Raised medians can also improve motorist safety when they replace two-way center turn lanes; however, desired turning movements need to be carefully studied and provided where necessary so that motorists are not forced to travel on inappropriate routes, such as residential streets, or make unsafe U-turns.
Continuous raised medians are not always appropriate. In some cases, separating opposing traffic flow and eliminating left-turn friction can increase traffic speeds by decreasing the perceived friction of the roadway. Raised medians may also take up space that can be better used for wider sidewalks, bicycle lanes, landscaped buffer strips, or on-street parking, and may cause problems for emergency vehicles. In some environments, raised medians can be constructed in sections, creating an intermittent rather than continuous raised median. Another good alternative device for two-, three- or four-lane roads is the crossing island, which provides a crossing landing for pedestrians and, in some designs, aids in decreasing vehicle speeds.
Raised medians are most useful on high-volume, high-speed roads, and they should be designed to provide tactile cues for pedestrians with visual restrictions to indicate the border between the pedestrian refuge area and the motorized vehicle roadway. Examples of designs demonstrating a range of quality for raised median crossings can be found in Chapter 8 of Designing Sidewalks and Trails for Access: Part II of II: Best Practices Design Guide.5
FHWA recommends particular consideration in areas with mixtures of significant pedestrian and vehicle traffic (more than 12,000 Average Daily Traffic) and intermediate or high travel speeds. They also recommend the medians be at least 4 feet wide (preferably 8 feet to accommodate pedestrian comfort and safety) and of adequate length to allow the anticipated number of pedestrians to stand and wait for gaps in traffic before crossing.9,10,11
