Transcript 13th Street and Dayton Avenue – Ames, IA Intersection Study

13th Street and Dayton Avenue –
Ames, IA
Intersection Study
ByungOck Kim
Greg Karssen
13th Street and Dayton Avenue Location
13th Street and Dayton Avenue –
Lane Configuration
Approach # 4
Approach #3
13th STREET
D
A
Y
T
O
N
A
V
E
Approach #2
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
East Approach
1
13900
North Approach
2
5933
West Approach
3
13900
South Approach
4
5933
Left turn
Thru
Right turn
13th Street and Dayton Avenue –
Crash History
Table 1: Crash Frequency
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…
Table 2: Crash Types
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
Left-turn collisions Large volume of left turns
absence of left-turn phase
excessive speed on approaches
Right-angle collisions excessive speed on approaches
inadequate signal timing
large total intersection volumes
Rear End Colissions
large number of turning vehicles
at signalized intersections
inadequate signal timing
Data Needs
volume data
Countermeasures
provide left turn signal phase
signal timing info
traffic conflicts
speed study
speed study
signal timing info
volume data
traffic conflicts
volume data
traffic conflicts
signal timing info
retime signal
already there?
Yes
No protected
turns on
North/South
reduce speed limit on approaches n/a
reduce speed limit on approaches n/a
retime signal
turn lanes
yes
left turn lanes
provide left turn signal phase
retime signal
all red phase
Yes
Yes
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 (throughright-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??
?