# Presentation: 479977

## Reducing Crash Severity at High Speed Isolated Rural Intersections: Considering Emergency Response Times and Implementation of Modern Roundabouts

- January 11, 2005
*Dwight D. Eisenhower *
*Transportation Fellowship Program Research Showcase*
- 84th Annual Transportation Research Board Meeting
- Washington, D.C.

- Hillary Isebrands
- Iowa State UniversityDepartment of Civil, Construction and Environmental Engineering

## Overview

-  Background
-  Relevant Literature
-  Data Collection and Analysis
-  Methodology
-  Summary

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Background

- Intersections
- Planned conflict points
- Safety initiatives
- FHWA
- Vital Few Priority – safety
- 20% reduction in fatalities and serious injuries by 2008
- State and local agencies

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Fatal Crash Statistics (2003 FARS Data)
49% - Nighttime
25% to 33% VMT
58% - Rural areas
28% - Intersection related
40% - Occur at night
42% - Occur in rural areas

- 49% - Nighttime
- 25% to 33% VMT
- 58% - Rural areas
- 28% - Intersection related
- 40% - Occur at night
- 42% - Occur in rural areas

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

- Background

## Problem Statement
Consistently high number of rural intersection crashes each year
Emergency response times for rural crashes tend to be higher
Roundabouts may potentially reduce speeds and crash severity at rural intersections
Scope of Research
Identify rural intersections with high crash severity
Evaluate emergency response times at rural intersections
Evaluate effectiveness of roundabouts as an alternative to traditional rural intersections

- Consistently high number of rural intersection crashes each year
- Emergency response times for rural crashes tend to be higher
- Roundabouts may potentially reduce speeds and crash severity at rural intersections
- Scope of Research
- Identify rural intersections with high crash severity
- Evaluate emergency response times at rural intersections
- Evaluate effectiveness of roundabouts as an alternative to traditional rural intersections

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

- Background

## Significance of Research
Increase safety 
Who benefits?
 Traveling public
 Local emergency response teams
 Insurance companies and employers

- Increase safety
- Who benefits?
-  Traveling public
-  Local emergency response teams
-  Insurance companies and employers

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

- Background

## Relevant LiteratureRoundabouts

- US Roundabouts
- Mostly urban or suburban
- NCHRP 3-65 does not address rural roundabouts in depth
- Rural Roundabouts - MD, KS, WA and OR
- Rural roundabouts
- Successful internationally
- Flexibility in Geometry
- Single lanes – low volumes
- Change in direction for primary route
- Skepticism
- High approach speeds
- Driver unfamiliarity
- Unbalanced flows
- Farm vehicles
- Land impacts

- http://www.jayz-web.com/nz_holiday

- http://www.awsairreels.com/

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Safety
Fewer conflict points

- Fewer conflict points

- Diverging	8Merging	8_Crossing__	__16_Total	32

- Diverging	4Merging	4_Crossing__	__0_Total	8

** ****Traditional 4-Approach Intersection                              4-Approach Roundabout**

- Relevant LiteratureRoundabouts

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

- Reduced speeds
- Changes the collision type

## Safety
Empirical Bayes observational before & after study (Persaud et al, 2001)
Crash Reduction
5 - Single Lane, rural, stop control intersections
 All crashes - 58%
 Injury Crashes - 82%

- Empirical Bayes observational before & after study (Persaud et al, 2001)
- Crash Reduction
- 5 - Single Lane, rural, stop control intersections
-  All crashes - 58%
-  Injury Crashes - 82%

- Relevant LiteratureRoundabouts

- Lothian, Maryland

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Safety
King County, WA

- King County, WA

| Injury Accident Statistics High-Speed Roundabouts vs. High-Speed Signals  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
| Category | Injury Accidents per 100 Million Vehicles |  |  |  |  |  |
|  | Fatal | Serious | Slight | Total | Number of
Sites | Average
Daily Traffic |
| Roundabouts
50–70 mph1 | 0.19 | 3.8 | 24.7 | 28.7 | 11 | 27,800 |
| Signals
45-55 mph2 | 0.56 | 11.8 | 39.2 | 51.5 | 8 | 20,400 |
| Novelty Hill Road,
Existing2 | 0.0 | 29.9 | 62.3 | 92.2 | 1 | 13,700 |
| Projected
Roundabout3 | 0.13 | 2.54 | 16.52 | 19.19 |  |  |
| 1   Maycock and Hall, “Accidents at 4-arm Roundabouts” 1984
2  WSDOT Accident Records and WSDOT Traffic Counts
3  Projections from RODEL Ltd. |  |  |  |  |  |  |

- Relevant LiteratureRoundabouts

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Washington County, OR (Rosales et al 2001)
Improve safety
Agricultural equipment
Large trucks
Minimize environmental impacts

- Improve safety
- Agricultural equipment
- Large trucks
- Minimize environmental impacts

- Relevant LiteratureRoundabouts

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Emergency Response Times in Rural Areas
Difficult to quantify
MO - Only 34% of rural emergency calls within 5 min (Brodsky, 1993)
MI - Rural motor vehicle crash occupants 2 times more likely to be involved in a fatal crash (Maio, 1993)
Potential gaps in emergency response district coverage
IA - Emergency Response Information System - ERIS

- Difficult to quantify
- MO - Only 34% of rural emergency calls within 5 min (Brodsky, 1993)
- MI - Rural motor vehicle crash occupants 2 times more likely to be involved in a fatal crash (Maio, 1993)
- Potential gaps in emergency response district coverage
- IA - Emergency Response Information System - ERIS

- Relevant LiteratureEmergency Response

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Data Collection and Analysis

- DOTs
- Intersections with crash problems
- Crash database from 1999 to 2003
- Rural intersections with high crashes
- Frequency
- Rates
- Severity
- Emergency Response Districts
- Coverage boundaries
- Location in relationship to problem intersections
- Response time estimates

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Data Collection and Analysis

- Aerial imagery
- Geometric features
- Land use
- Environmental features
- Field visits

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Methodology

- ArcGIS
- Map EMS response coverage areas
- Comparative analysis
- Emergency response times
- Rural v. non-rural
- Siting roundabouts

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Summary

- Intersections
- Planned conflict points
- High fatal crash statistics
- Federal, state and local governments
- Reduce crash severity - intersections
- Roundabouts
- Reduction in crash severity
- Safer intersection alternative
- Emergency response times
- Difficult to quantify
- Response times tend to be higher

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

- Rural intersection + High crash severity + Long emergency response time = Safety Problem

- Solution    Roundabout

## References

- Crown, R.  Achieving Excellence and Safety in Roundabout Design.  Presented at the 2004 Institute of Transportation Engineers Technical Conference in Irvine, CA.
- Federal Highway Administration
- Kansas State University
- Maycock. G., R.D. Hall. Accidents at 4-arm roundabouts. Transport and Road Research Laboratory, Laboratory Report LR1120. 1984
- Persaud B., R. Retting, P. Garder and D. Lord.  Safety Effect of Roundabout Conversions in the United States: Empirical Bayes Observational Before-After Study. Transportation Research Record, No. 1751. 2001. pp 1 - 8.
- King County, Washington
- Rosales J., K Austin, and R. Morast. Improving Safety and Accommodating Future Traffic in Rural Areas with Double Lane Roundabouts.  Presented at the 2001 Institute of Transportation Engineers Annual Meeting in Chicago, IL.
- Roundabouts: An Informational Guide, FHWA, 2000
- Washington State Department of Transportation, “Injury Accident Statistics – High Speed Roundabouts vs. High Speed Signals”. Unpublished. 2004.

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## Questions?

- http://www.jayz-web.com/nz_holiday

- Lothian, Maryland

*Reducing Crash Severity at High Speed Isolated Rural Intersections*

## January 11, 2005

Dwight D. Eisenhower 
Transportation Fellowship Program Research Showcase

84th Annual Transportation Research Board Meeting
Washington, D.C.

*Dwight D. Eisenhower *
*Transportation Fellowship Program Research Showcase*
- 84th Annual Transportation Research Board Meeting
- Washington, D.C.

- Hillary Isebrands
- Iowa State UniversityDepartment of Civil, Construction and Environmental Engineering

**Reducing Crash Severity at High Speed Isolated ****Rural Intersections: Considering Emergency Response Times and Implementation of Modern Roundabouts**