Engineering Analysis for Tom McCall Intersection improvements workshop held with Crook County Court and Prineville City Council.

1. OR126/Tom
McCall
Intersection
Improvements
August 2, 2016

2. Traffic Engineering Analysis
 Operational Analysis
– Utilize Highway Capacity Manual
• Volume-to-capacity ratio
• Delay
• Level-of-service
• Queues
 Safety Analysis
– Utilize Highway Safety Manual and supplementing research
• Crashes per year
• Severity

3. Existing Intersection Operations

4. Existing Intersection Safety Performance
 5 years of historical crash data
– Total Number of Crashes: 12
– Total Injuries: 12

5. How does a roundabout compare to a signal?
Year 2035 Operations – Average Delay per Vehicle
> 80s
~ 29s (With left-turn lanes)
29s (Single-lane roundabout)
24s (With NB right-turn lane)
OR126/Tom McCall
Vehicle stacking
Queues are approximately half as
long with roundabout vs. signal

6. How does a roundabout compare to a signal?
Future Safety Performance over 5 Years
6.5 Total Crashes
3.4 Fatal/Injury
3.6 Total Crashes
3.3 Fatal/Injury
1.9 Total Crashes
0.4 Fatal/Injury
71% reduction
87% reduction
OR126/Tom McCall
44% reduction
3% reduction

7. Questions?

8. 73’
130’

9. 112’
113’
73’

10. Roundabouts reduce crashes
 Over 90% reduction in fatalities
 76% reduction in injuries
 35% reduction in total crashes
* NCHRP Report 572
Photo:LeeRodegerdts

11. Safety Performance (NCHRP Report 572)
 78% reduction in injuries
 48% reduction in total crashes
CONVERTED TO