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Segment Crash Analysis. 6/2011. PE Services Roadway Begin/End Facility Type (2-lane) Rumblestrips. Analysts Rural/Urban Crash history Weighed ADT Distance Edge Risk Assessment Shoulder Type and Width Access Density Passing Zones. Information Gathering. Gravel Roads.
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Segment Crash Analysis 6/2011
PE Services Roadway Begin/End Facility Type (2-lane) Rumblestrips Analysts Rural/Urban Crash history Weighed ADT Distance Edge Risk Assessment Shoulder Type and Width Access Density Passing Zones Information Gathering
Gravel Roads • Leave Gravel roads in the segment list • Be sure to note that its gravel • Gather crashes and ADT for segments, DO NOT get ERA & Access Density • DO NOT include in Rural Road Prioritization
Crash Selection • Typically use Route Segment function • Search Distance: 25’ • Select All Crashes • Years: 2006-2010
Duplicate Crashes • To be removed in Excel with Macro • Order of Priority • Assigned to officer coded roadway • Assigned to lower RP (typically W>E, S>N)
ADT • Calculate weighted corridor ADT • 30% of segment – 100 ADT • 70% of segment – 150 ADT • Weighted Average – 30%*100+70%*150 = 135 ADT • Use most recent ADT information • Add text in the Excel file for documentation
Distance • Options for gathering this data: • Google Maps • Bing (Live) Maps • ArcMap data from Mn/DOT • Determine distance to the nearest 0.1 mile.
Edge Risk Assessment 1– Usable Shoulder, Reasonable Clear Zone • Be sure to add info about 2 2– No Usable Shoulder, Reasonable Clear Zone 2– Usable Shoulder, Roadside with Fixed Obstacles 3– No Usable Shoulder, Roadside with Fixed Obstacles
Shoulder Width/Type • Gather shoulder type and width as part of the ERA drive • Be approximate with the width. 2’, 4’, 8’, 12’ etc.
Access Density Depends on if segment is continuous or not • Road Access • Count each leg that intersects • Count only beginning termini for continuous segments • County beginning and end termini's for the last segment • Commercial • Residential/Farm Access 1 3 5 7 9 2 4 6 8 10
Passing Zones The distance between samples is : • 0-<2 mile segments, use 1,820 foot spacing • 2+ mile segments, use 3,140 foot spacing • NOTE: One concern was the use of the ½ and ¼ mile spacing of the samples would often fall at the typically 1-mile spaced intersections. So instead of the exact ½ and ¼ miles spacing, the decision was to go 500’ more.