Grand Ave & Duff Ave

Craig

&

James

CE 550

4/18/2007

Problem Statement

Grand Ave/Duff Ave intersection is on the northeast part of Ames, with 36,600 vehicles entering the intersection each day.

Figure 1 Grand Ave/Duff Ave Interesection

Problem Statement (Cont’) There were 33 crashes

in this intersection during 2001~2005 period. Figure2 shows the summary of these crashes. The average property damage is $4,214.

Crash Summary

Unknow n12%

Property Damage Only

73%

Minor Injury9%

Major Injury6%

Fatal0%

Figure 2

Figure 3

Problem Statement (Cont’) ‘Ran Traffic Signal’ and ‘Making Left Turn’

are the two major causes, which take about 79% of the total crashes.

Major Cause Summary(2001~2005)

02468

10121416

Ran Traffic Signal Making Left Turn Made ImproperTurn

Other Unknown

Problem Statement (Cont’) It is surprised to

discover that ALL the crashes by last 5 years are related to alcohol.

Figure 4

’Making Left Turn’ Crashes

As there is no left-turn protected traffic lights in this intersection, usually the left-turn vehicles on the Grand Ave will pull upward a little bit to make an easy left-turn. This is the typical situation when a crash will happen.

One Crash in June 2002

Possible Solutions Majority – Left-turn incidents Garber & Hoel

Create one-way streetWiden roadProvide left-turn signal phaseProhibit left turnsReroute left-turn trafficChannelize intersectionRevise Signal Sequence

Possible Solutions

Traffic SignalsRetime Signals

Increase amber phase Longer all-red phase

Advanced Warning

Recommended Solution

Left-turn Incidents Grand Ave

Majority of IncidentsProtected left-turn only

Duff AveTurning bays for left-turnProtected left-turn only

Recommended Solutions

Traffic signals

Retime signals

Collect data on signal sequence

References Crash Mapping Analysis Tool, Version 3.6.0. Developed

by Center for Transportation Research and Education at Iowa State University. PI: Dr. Reg Souleyrette. Lead Software Developer: Nick Burdine. Copyright 2002-2005.

Crash Report Diagrams and Narratives. Prepared for use by the Iowa Department of Transportation, Office of Traffic Safety.

Iowa’s GIS-SAVER:E5. Iowa Department of Transportation, Office of Traffic Safety. Dr. Michael D. Pawlovich.

Garber and Hoel. Traffic and Highway Engineering, 3rd edition. 2002.

Questions ??

Thank you. ☺