Crash Data: How Kentucky Improved Their System

Eric Green, MSCE, PE, GISPUniversity of Kentucky

Kentucky Transportation Center

Improving Crash Data in Kentucky

• Traffic Records Committee (KTRAC)• Crash Location Research• Crash Query software• Crash Mapping (GIS)• Safety Circuit Rider Program• HSM

KTRAC

• SAFETEA-LU• Section 408• Programs to improve the timeliness,

accuracy, completeness, uniformity, integration, and accessibility of traffic safety programs

Crash Locations

• Location, location, location• GPS units issued to police in 2000• Evaluated accuracy of location data in

2004– Recommendations made– Software developed

Paper Reports• Submitted manually• GPS from Magellan,

Google® Maps, 911 system

• County, Route and Milepoint (CRMP) using reference system

Map Click

eCrash KYOPS• MapIt• Added October 1st

2007• CRMP data linked

to GPS• Between/Intersect

streets• Searchable• RT Unique:“034-US-0068 -000”

9

Crash Locations

• Follow-up study in 2010• Investigated crash data since the

MapIt system was added to eCrash

Crash Data Potted by Lat/Long

Crash Data plotted by Lat/Long Showing County Check

Conclusions and Recommendations

• 92% of all crashes were accurate compared to around 50% in the previous study

• Most of this improvement can be attributed to the implementation of the MapIt system in eCrash

• A large majority of incorrectly located were largely due to a lack of reference points

• The MapIt system currently requires user to know where they are on a map

• Identified errors should be investigated by KYOPS

Potential Improvements• Aerial photos• Integrated GPS receivers• Reference log data

– Mileposts, bridges, culverts, etc.• Training

– QC of location data• Contact specific agencies or evaluate county data• ‘Distance From’ glitch• Edits to check for county and distance between

CRMP and GPS

Critical Rate Calculator CRC

CRC Results

Buildup

Buildup – Results

Public Crash Website

Crash Results

Map Results

Secured Crash Website

Crashes by Type

Crash Densities

1 F = 12 PDO1 I = 3 PDO

Safety Circuit Rider

• KY LTAP Stared in 2005• SCR: Todd Morrison

– Retired engineer from KYTC D3• Technical assistance to counties and

cities• Safety improvement workshop• Focus counties• RSA

Safety Circuit Rider

Highway Safety Manual

• Science-based• Combines predicted and actual

crashes• Doesn’t assume crashes are normally

distributed• 10 years in the making

Safety Performance Function

Four-Lane Divided Road - Total Crashes Per Year

General Form of PredictionMethodology

WHERE:

N = predicted accidents per year (road

segment or intersection)

Nbase = predicted accidents per year - base conditions

C = calibration factor - convert predicted accidents to local conditions

AMFn = accident modification factor – adds effects of specific site situation to base conditions

Highway Safety Manual

• Safety Analyst• www.highwaysafetymanual.org • FHWA-NHI-380106:

– Google search above– 12 Hours– Free!

Questions?

• Eric Green, GISP, MSCE, PEKentucky Transportation CenterResearch Engineer140C Raymond BuildingUniversity of KentuckyLexington, KY 40506-0281  egreen@engr.uky.eduPhone: (859) 257-2680