13th Street and Dayton Avenue – Ames, IA
Intersection StudyByungOck Kim
Greg Karssen
13th Street and Dayton Avenue - Location
13th Street and Dayton Avenue – Lane Configuration
13th STREETD A Y T O N
A V E
Approach #2
Approach # 4
Approach #3
13th Street and Dayton Avenue – Images
13th Street and Dayton Avenue – Images
Looking west
Looking south
Looking east
Looking north
13th Street and Dayton Avenue – Traffic Volumes
Intersection Approach Label in Figure 2 AADT Left turn Thru Right turn
East Approach 1 13900
North Approach 2 5933
West Approach 3 13900
South Approach 4 5933
13th Street and Dayton Avenue – Crash History
Table 1: Crash Frequency
Table 2: Crash Types
MAJOR CAUSES
(7) Failure to Yield ROW – Left Turn(4) Ran Traffic Signal(3) Following Too Close (Rear End)(2) Driving Too Fast for Conditions
**Signalized intersection crashes…
Crash Diagram• This diagram shows the
major injury crashes were angle collisions involving a turning vehicle and a vehicle proceeding through the intersection
13th Street and Dayton Avenue – Crash Countermeasures
Crash Pattern Probable Cause Data Needs Countermeasures already there?Left-turn collisions Large volume of left turns volume data provide left turn signal phase Yes
absence of left-turn phase signal timing info retime signal
No protectedturns onNorth/South
traffic conflictsexcessive speed on approaches speed study reduce speed limit on approaches n/a
Right-angle collisions excessive speed on approaches speed study reduce speed limit on approaches n/ainadequate signal timing signal timing info retime signallarge total intersection volumes volume data turn lanes yes
traffic conflictsRear End Colissions large number of turning vehicles volume data left turn lanes Yes
at signalized intersections traffic conflicts provide left turn signal phase Yesinadequate signal timing signal timing info retime signal
all red phase Yes
13th Street and Dayton Avenue – Recommendation #1
• Left turn Signal phase– Evaluate signal times
for left turns on EB/WB approaches
– Provide exclusive left turns for NB/SB approaches…special concern for trucks and sight problems
Looking north…imagine a truck here
13th Street and Dayton Avenue – Recommendation #2
• P-Turn, “quadrant intersections”– Unconventional turns– Two right turn
movements (through-right-right) replace single left turn movement
• Follow vehicle on street B as it moves to street A Source: FHWA
13th Street and Dayton Avenue – Recommendation #3
• Offset Left Turn Lanes
– Improves sight distance for left-turning vehicles
– The left turning vehicle can see around the opposing left turning vehicle
Questions??
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