Bayesian methodology incorporating expert judgment for ranking countermeasure effectiveness under uncertainty: Example applied to at grade railroad crossings in Korea

This paper describes the formalization and application of a methodology to evaluate the safety benefit of countermeasures in the face of uncertainty. To illustrate the methodology, 18 countermeasures for improving safety of at grade railroad crossings (AGRXs) in the Republic of Korea are considered. Akin to “stated preference” methods in travel survey research, the methodology applies random selection and laws of large numbers to derive accident modification factor (AMF) densities from expert opinions. In a full Bayesian analysis framework, the collective opinions in the form of AMF densities (data likelihood) are combined with prior knowledge (AMF density priors) for the 18 countermeasures to obtain ‘best’ estimates of AMFs (AMF posterior credible intervals). The countermeasures are then compared and recommended based on the largest safety returns with minimum risk (uncertainty). To the author's knowledge the complete methodology is new and has not previously been applied or reported in the literature. The results demonstrate that the methodology is able to discern anticipated safety benefit differences across candidate countermeasures. For the 18 at grade railroad crossings considered in this analysis, it was found that the top three performing countermeasures for reducing crashes are in-vehicle warning systems, obstacle detection systems, and constant warning time systems.

Field evaluation of innovative active warning devices for use at railroad-highway grade crossings /

"August 1988."

Experimental design for evaluating the safety benefits of railroad advance warning signs /

Mode of access: Internet.

Accident prediction model for railway-highway interfaces

Considerable past research has explored relationships between vehicle accidents and geometric design and operation of road sections, but relatively little research has examined factors that contribute to accidents at railway-highway crossings. Between 1998 and 2002 in Korea, about 95% of railway accidents occurred at highway-rail grade crossings, resulting in 402 accidents, of which about 20% resulted in fatalities. These statistics suggest that efforts to reduce crashes at these locations may significantly reduce crash costs. The objective of this paper is to examine factors associated with railroad crossing crashes. Various statistical models are used to examine the relationships between crossing accidents and features of crossings. The paper also compares accident models developed in the United States and the safety effects of crossing elements obtained using Korea data. Crashes were observed to increase with total traffic volume and average daily train volumes. The proximity of crossings to commercial areas and the distance of the train detector from crossings are associated with larger numbers of accidents, as is the time duration between the activation of warning signals and gates. The unique contributions of the paper are the application of the gamma probability model to deal with underdispersion and the insights obtained regarding railroad crossing related vehicle crashes. Considerable past research has explored relationships between vehicle accidents and geometric design and operation of road sections, but relatively little research has examined factors that contribute to accidents at railway-highway crossings. Between 1998 and 2002 in Korea, about 95% of railway accidents occurred at highway-rail grade crossings, resulting in 402 accidents, of which about 20% resulted in fatalities. These statistics suggest that efforts to reduce crashes at these locations may significantly reduce crash costs. The objective of this paper is to examine factors associated with railroad crossing crashes. Various statistical models are used to examine the relationships between crossing accidents and features of crossings. The paper also compares accident models developed in the United States and the safety effects of crossing elements obtained using Korea data. Crashes were observed to increase with total traffic volume and average daily train volumes. The proximity of crossings to commercial areas and the distance of the train detector from crossings are associated with larger numbers of accidents, as is the time duration between the activation of warning signals and gates. The unique contributions of the paper are the application of the gamma probability model to deal with underdispersion and the insights obtained regarding railroad crossing related vehicle crashes.

Boston, Massachusetts -- Railroads, 1850 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Rail-road crossings and termini in the vicinity of Boston, E.S. Chesbrough, commissioner ; reduced from a drawing by Chas. Perkins. It was published in 1850. Scale [1:7,200]. Covers Boston proper (Shawmut Peninsula and Boston Neck) and portions of Cambridge and Somerville, Massachusetts. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as railroads, railroad depots, railroad crossings, road, drainage, some public buildings, bridges, wharves, and more. Relief is shown by hachures. The accompanying profiles of railroad crossings are published separately under the title: Sections of railroad crossings in the vicinity of Boston. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

Crossing safety improvement program FY ... : proposed grade crossing protection fund projects for local roads and streets.

"On July 30, 1998 Public Act 90-659 was signed into law requiring the Illinois Commerce Commission to publish annually a five year plan of projected safety improvements at public railroad crossings on local roads."

A compilation of the laws of the forty-eight States relating to the protection of the public at points where railroads intersect highways at grade, including grade crossing elimination acts--Supplement.

Mode of access: Internet.

Motorists' requirements for active grade crossing warning devices /

Mode of access: Internet.

STIP Statewide Transportation Improvement Program 2017-2022

The South Carolina Statewide Transportation Improvement Program is the six-year transportation improvement program for all projects and program areas receiving federal funding, including pavements, bridges, upgrades, freight, safety, congestion mitigation and air quality, transportation alternatives program, railroad crossings, planning, State Infrastructure Bank payments, preventative maintenance and operations, and public transportation. The STIP is formatted to include summaries of statewide programming, as well as project information by county. In addition, regional project tables are included to account for multi-jurisdictional projects.

Evaluation of experimental railroad-highway grade crossings in Louisiana. Interim report no. 6.

Mode of access: Internet.

Evaluation of retroreflective markings to increase rail car conspicuity -- safety of highway-railroad grade crossings.

Transportation Systems Center, Cambridge, Mass.

Legal effects of use of innovative equipment at railroad-highway grade crossings on railroad's accident liability. Final report.

Federal Railroad Administration, Office of Safety, Washington, D.C.

Enhancements to passive warning devices at railroad-highway grade crossings.

Texas Department of Transportation, Austin

Summary statistics of the national railroad-highway crossing inventory for public at-grade crossings. Final report.

Federal Railroad Administration, Office of Policy and Program Development, Washington, D.C.