Friday, December 13, noon to 1
Presentation by Ryan Greene-Roesel, Senior Transportation Planner at the San Francisco County Transportation Authority
Vew the slides and listen to the presentation remotely at: http://escholarship.org/uc/item/4fq4q450(link is external)
The state of the practice in safety has advanced rapidly in recent years with the emergence of new tools and processes for improving selection of the most cost-effective safety countermeasures. However, many challenges prevent fair and objective comparisons of countermeasures applied across safety disciplines (e.g. engineering, emergency services, and behavioral measures). These countermeasures operate at different spatial scales, are funded often by different financial sources and agencies, and have associated costs and benefits that are difficult to estimate.
This research proposes a methodology by which both behavioral and engineering safety investments are considered and compared in a specific local context. The methodology involves a multi-stage process that enables the analyst to select countermeasures that yield high benefits to costs, are targeted for a particular project, and that may involve costs and benefits that accrue over varying spatial and temporal scales.
The methodology is illustrated using a case study from the Geary Boulevard Corridor in San Francisco, California. The case study illustrates that: 1) The methodology enables the identification and assessment of a wide range of safety investment types at the project level; 2) The nature of crash histories lend themselves to the selection of both behavioral and engineering investments, requiring cooperation across agencies; and 3) The results of the cost-benefit analysis are highly sensitive to cost and benefit assumptions, and thus listing and justification of all assumptions is required. It is recommended that a sensitivity analyses be conducted when there is large uncertainty surrounding cost and benefit assumptions.
Ryan Greene-Roesel is a Senior Transportation Planner at the San Francisco County Transportation Authority with experience in performance measurement and policy analysis applied to road safety. She was the lead researcher for NCHRP 17-46, A Comprehensive Analysis Framework for Safety Investment Decisions, which involved developing methods to compare engineering, enforcement, and education-based safety strategies. She formerly worked at Cambridge Systematics and at SafeTREC, where she helped author a guidebook for Caltrans on measuring pedestrian exposure to collisions.