MRIGlobal Research Advances Safety in Highway Design
MRIGlobal is a leading center for research on the relationship between highway geometric design and safety.
MRIGlobal conducts research on the safety of design elements, including lane width, roadside slopes, median types, treatments for left and right turns, interchange ramps, and speed-change lanes, among other elements.
MRIGlobal has extensive experience in multivariate statistical modeling of relationships between design and safety, before and after evaluations of geometric design improvements, and development of practical geometric design policies using research results.
- Research on the safety of design elements:
- Lane and shoulder width
- Horizontal alignment
- Vertical alignment
- Sight distance
- Roadside slopes and clear zones
- Median types and widths
- Passing lanes
- At-grade intersections
- Left- and right-turn treatments
- Interchange ramps and speed-change lanes
- Work zone taper length, median crossover designs, and barrier applications
- Policy development
- Development of design and guidelines, manuals, and handbooks
MRIGlobal’s Geometric Design/Safety Relationship Research Successes:
- Policy development: MRIGlobal research on intersection sight distance and divided highway median widths was incorporated into the American Association of State Highway and Transportation Officials (AASHTO) Policy on Geometric Design for Highways and Streets, also known as the Green Book. MRIGlobal prepared the AASHTO Guidelines for Geometric Design of Very Low-Volume Local Roads and key portions of the AASHTO Highway Safety Manual.
- Computer tools for safety evaluation: MRIGlobal played an active role in planning and developing the Interactive Highway Safety Design Model (IHSDM), a series of computer tools to provide an explicit evaluation of the safety performance of proposed designs, for the Federal Highway Administration. MRIGlobal contributed to IHSDM modules for accident prediction, diagnostic review of at-grade intersection designs, geometric design consistency, driver/vehicle performance, and traffic analysis.
- Technology transfer: MRIGlobal prepares research reports, manuals, guidelines, handbooks, design policies, benefit/cost and cost-effectiveness procedures, and resource allocation procedures.
Engineer Contributes to MRIGlobal’s Legacy in Traffic Safety Guidelines
MRIGlobal’s traffic engineers have been responsible for key portions of America’s traffic safety policies and guidelines, including the Transportation Research Board’s Highway Capacity Manual, the Federal Highway Administration’s Manual on Uniform Traffic Control Devices, and the AASHTO Policy on Geometric Design for Highways and Streets.