39TH INTERNATIONAL FORUM ON TRAFFIC RECORDS & HIGHWAY

INFORMATION SYSTEMS

D . B R E T T H A R R E L S O N , P E

S T A T E S A F E T Y E N G I N E E R

S C D O T

O C T O B E R 3 0 , 2 0 1 3

SCDOT Collision Diagram Tool

Background

South Carolina is 40th largest state

Average 100,000 crashes per year

Average 800-900 fatalities per year

SC has 4th largest state maintained roadway system

Over 41,000 miles of roadway

Approx 95 % of fatalities and 90% of all collisions

SC Safety Rankings – 2011

Mileage death rate – 3rd

Population death rate – 9th

DUI death rate – 1st

Motorcycle death Rate – 2nd

Bicycle death rate – 5th

Pedestrian death rate – 9th

Speed related death Rate – 2nd

Purpose

SCDOT produces approximately 300 diagrams per year

SCDOT wanted a way to automate the diagram process

Wanted a tool designed to work within SCDOT’s RIMS system

Create consistency

among diagrams

(among personnel)

Goals

SCDOT’s Goal was for the CD Tool to be used two ways:

1. As an on-demand tool for specific requests

2. As a support system in determining all safety concerns based on a statewide ranking

Faster way to complete diagrams

Software to mirror current diagram product

Create a “one stop shop” for generating a crash diagram

MicroStation Process

Labor intensive – approx. 1 hr to complete average size diagram

Requires staff to be proficient in MicroStation

MicroStation is a learned skill, not just computer knowledge

Uses multiple resources to combine geometry, roadway data and crash data

Requires hand tallies and calculations

MicroStation Process

Obstacles

Turning handwritten drawing into electronic data

Obstacles

Code and validation rules had to be designed to transform written report into symbols on diagram

Rules specific to SCDOT and SC’s crash form

Relies on the accuracy of the investigating officer Direction of Travel

Manner of Collision

Orientation of routes (N,S vs. E,W)

Challenge fitting all possible crash types on diagram

Complexity of Plotting a Crash

CD Tool relies on codes from the crash report

Complexity of Plotting a Crash

All crash types possible on x-type intersection diagram

264 Possible plotting locations

20 zones, 17 symbols

Complexity of Plotting a Crash

All crash types possible on section diagram

CD Tool Capabilities

CD Tool can generate diagrams from a standard query or from the state Rank table

CD Tool can generate diagrams for sections, X-type intersection and T-type intersections

Section length limited to 0.5 miles

Intersections limited to 4 legs

Standard Query Statewide Ranking

Generating a Collision Diagram

On-demand access

Network screening

CD Tool Interface

Four major components

Basic Information Tab

Crash Data Tab

Diagram Legend Tab

Diagram Archive Tab

Basic Information Tab

Automatically generated based on user’s query

Linked to roadway data tables

North arrow can be rotated

Crash Data Tab

• Automatically assigns a symbol and plotting zone based on crash details

• User can edit crash to plot in the correct spot or exclude the crash from the diagram

Hyperlinked Crash Reports

Editing Crash Data

Crash data can be edited to correct location and symbol or it can be excluded from diagram. Check box included to let other users know a crash has been reviewed and verified. Goal of user is to clear out the “Cannot Plot” section

Generating a Diagram

Once all crash data is edited/verified the user can generate a crash diagram from the “Crash Data” tab

Diagram file name is automatically generated to include route, local name, crossing milepoint and date – can also be edited by user

Linking to Crash Rankings

02-2012 CD

07-2012 CD

10-2013 CD

Completed Diagram – page 1

Completed Diagram page 2

Benefits of Automated CD Tool

Up to 50% time savings vs. drawing each location individually to site specific conditions using MicroStation

Diagrams are stored in a central location with all users having access to diagrams

The latest diagram is readily available

No human error when calculating rates, date range, etc.

Diagrams are completed with the latest roadway information (AADT, road names)

CD Tool only as good as crash data

Crash listed as “head on” in code

Future Enhancements

Add total number of crashes beside each symbol on finished collision diagram

Include turning lanes on diagram layout

Improved accuracy of plotted crashes with enhancements to the crash data

Questions