an evaluation of wildlife crossings for mule deer and other wildlife in nevada

Center for Advanced Transportation Education and ResearchUniversity of Nevada, Reno

Student PaperIvy Attah

AN EVALUATION OF WILDLIFE CROSSINGS FOR MULE DEER AND OTHER WILDLIFE IN

NEVADA

Ivy Attah

Zong Z. Tian (PhD) Center for Advanced Transportation Education and Research

Department of Civil & Environmental Engineering

University of Nevada, Reno

Email: [email protected]

1



Outline

Introduction Background Methods Results Conclusions



Introduction

Observed high mortalities of mule deer along U.S Highway 93 in Elko County.

• During Spring and Autumn migrations.

75 - 150 known deer killed seasonally; estimated total of approximately 300 deer killed per year.

This lead to construction of several overpasses and underpasses to mitigate issue.



Background Approximately 1.5 million deer-vehicle

collisions occur resulting in:

Over 29,000 human injuries, 200 human fatalities, 1.3 million deer fatalities, and over 1 billion dollars worth of property damage in the United States.

200,000 deer killed on U.S. roadways in deer vehicle collisions in 1980.

An estimate of more than 538,000 deer killed by vehicles in the United States in 1991.

In 2002, NDOT reported 698 collisions between large ungulates and motor vehicles throughout the state.



Objectives

Evaluate the effectiveness of the US Highway 93 wildlife overpass in reducing DVCs by conducting: • A Before-After study on crash reductions• A Benefit-Cost Analysis

Analyze discrepancies with DVC data and Carcass removal data



Deer Collisions by Month on US 93 of Wells, NV FOR 2000-2004

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

0 20 40 60 80 100 120

Mortalities

Collisions



Methods Overview



Methods Overview Cont.



Methods Overview Cont.

Benefit-Cost Estimate-• Purpose- To determine the economic justifiability of having

wildlife crossings at high deer vehicle locations.

• Quantifies and compares benefits and costs of a project to determine if it is a sound investment.

• Costs- Largely construction oriented in present terms (design, implementation, maintenance and removal efforts)

• Benefits- Distributed more uniformly over the life of the project.

• Includes savings accrued by reducing the number of crashes.• Effectiveness of mitigation measures in reducing collisions



Case Study

Before-After Study

Treatment Group Comparison Group

Before (2001-2010) K=30 M =17

After (2011) L= 1 N = 2

thus a reduction in the expected number of crashes by 2.53.

ʎ = L

rc = N/M = 2/17 = 0.1176

π = rcK = 0.1176*30 = 3.528

δ = π- ʎ = 2.528,

Year 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Total

Crashes 0 4 0 1 8 2 6 4 2 3 30



Case Study Cont.11

• E-B Method

)582.23

5066.0(*101

1

8232.0

30*)8232.01()582.23(*8232.0}/{ KkE 717.24}/{ KkE

SPFNEVADA = Cr*SPF

SPF = 0.02652×ADT^0.53, AMF=0.95



Case Study Cont.

Year 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Total

ADT 5060 5270 5350 5200 5200 5050 5500 5400 5200 5200

Accidents 0 4 0 1 8 2 6 4 2 3 30

μ year(mile-year)2.436 2.489 2.509 2.472 2.472 2.434 2.546 2.522 2.472 2.472 24.823

(μyear)*AMF2.314 2.365 2.384 2.348 2.348 2.312 2.419 2.396 2.348 2.348 23.582

Expected accidents/yr 9.988 10.206 10.288 10.134 10.134 9.978 10.440 10.339 10.134 10.134 101.774

Expected Annual Acc for Segment (μyear/∑μyear)

2.426 2.479 2.498 2.461 2.461 2.423 2.535 2.511 2.461 2.461 24.717

..ds 717.24)8232.01( 091.2

Thus, the expected accidents = 24.72 ± 2.09 accidents in 10yrs.



Case Study Cont.

Benefit-Cost Analysis (i = 4%, n = 40 years)

CONSTRUCTION COST (CC)

Approximate cost of overpass $2,018,000

Backfill and Top Soil $112,085

Fencing and Vegetation $196,150

Maintenance Cost (annual) $3,363 Total Construction Cost $2,329,598.00

COST ASSOCIATED WITH DEER-VEHICLE COLLISIONS (DC, IC, FC)

Damage Cost (DC) (2011) $7,625.16

2003 Utah data adjusted to 2011 $1,941.32

Value of deer in Nevada (2011) $4,990.04

2011 value of hunters’ travel, food, lodging, equipment, etc. $693.81

Injury Cost (IC) (2011) $91,091.74

Fatality Cost (FC) (2011) $3,068,359.10 Total Collision Cost $3,174,701.00

Total $5,504,299.00



NPW = {(DC) (PD) + (IC) (PI) + (FC) (PF)} (N) (PWF) – {CC + (MC) (PWF)}

NPW = {7625.16 *0.9591 + 91,091.74*0.0407 + 3,068,359.10*0.0002} (10.4*3.5*0.90)*19.79– {2,329,598+3,363*19.79)

NPW= $5,146,665million

B/C ratio = 3.15

Case Study Cont.14



Wildlife Crossings US 93 in Wells, Nevada

OverpassUnderpass



Practical Results



Conclusions

The Empirical Bayes method provides a more accurate estimate compared with other methods.

• Combines crash counts with knowledge about the safety of similar entities

• Corrects the regression-to-the-mean bias

A reduction of 17.6% crashes gives overpass some credibility of effectiveness

A B/C ratio of 3.15 proves that wildlife crossings are economically justifiable.



Thank You!Slow down

for Deer

an evaluation of wildlife crossings for mule deer and other wildlife in nevada

Documents

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