NCHRP Research Report 900 will assist in the selection of alternative access management techniques based the safety and operation performance of each affected travel modes. It documents operational and safety relationships between access management techniques and the automobile, pedestrian, bicycle, public transit, and truck modes; and consolidates the body of knowledge on the safety and operation effects of each technique on each travel mode. The safety, operational, and other analyses in the guide generally reflect a suburban/urban land use context. The material in this report will be of immediate interest to practitioners involved in how to weigh, evaluate, and understand the effects and trade-offs when implementing access management techniques in a multimodal corridor.
The roadway system must accommodate many types of users – bicycles, passenger cars, pedestrians, transit, and trucks. Increasingly, stakeholders are recognizing that there should be an appropriate balance among the various modes. Access connections to the roadway are a part of the system, and there is increasing recognition that the location and design of access to and from roadways impacts all transportation modes. As the emphasis on considering all users grows, there is a need to better understand the interactions between multimodal operations and access management techniques and treatments, and the tradeoff decisions that must be made. In addition, suburban and urban land uses continually redevelop, and access management planning for retrofitting corridors should consider the multimodal needs as well as the need to upgrade arterial performance. Past studies have shown that arterial roadway characteristics such as turning movements, unsignalized and signalized access density, median type, turn-lanes, sidewalks, bike lanes, and bus turnouts can affect corridor operations. Studies have also shown that effective access management treatments reduce conflict points along roadways, leading to reductions in delays and crashes. However, there was limited understanding of the effects of access management treatments on multimodal operations, and vice versa, particularly treatments in combination. As a result, quantitative relationships to assess measures-of-effectiveness of access management techniques and multimodal interactions for, but not limited to, average travel speed; travel time reliability; and capacity preservation were needed.
Under NCHRP Project 03-120, Kittelson and Associates, Inc was asked to identify and determine unknown relationship definitions between access management techniques and the various users/modes along multimodal corridors. Performance relationships and priorities may differ under a central business district context. The guide is not intended to supersede engineering judgment by the knowledgeable design professional. Specific combinations of characteristics in other environments may produce outcomes that differ from those presented herein. The fact that new operational and safety performance relationships are presented herein does not imply that existing roadways or highways are unsafe, nor does it mandate the initiation of improvement projects.
The research agency’s final report that documents the entire research effort is available as NCHRP Web-Only Document 256: Assessing Interactions between Access Management Treatments and Multimodal Users