Western Federal Lands Highway Division

Yale-Kilgore Road Safety 

and Traffic Assessment 

SAFETY DATA CASE STUDY 

FHWA-SA-21-073 

Federal Highway Administration Office of Safety 

Roadway Safety Data Program 

http://safety.fhwa.dot.gov/rsdp
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SAFETY DATA CASE STUDY FHWA-SA-21-073

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SAFETY DATA CASE STUDY FHWA-SA-21-073

1. Report No.

FHWA-SA-21-073

2. Government Accession 

No.

3. Recipient's Catalog No.

 

4. Title and Subtitle

Yale-Kilgore Road Safety and Traffic Assessment

5. Report Date

May 2021

6. Performing Organization Code

7.Author(s) 

Ian Hamilton and Dylan Coley

8. Performing Organization Report No.

9. Performing Organization Name and Address

Vanasse Hangen Brustlin, Inc (VHB)

940 Main Campus Drive 

Raleigh, NC 27606 

10. Work Unit No.

11. Contract or Grant No.

DTFH61-16-D-00052

12. Sponsoring Agency Name and Address

Federal Highway Administration Office of Safety 

1200 New Jersey Ave., SE

Washington, DC 20590

13. Type of Report and Period

Case Study, January 2020-January 

2022

14. Sponsoring Agency Code

FHWA

15. Supplementary Notes

The contract manager for this report was Jerry Roche. Funding for this effort provided in part by the Highway Safety 

Manual Implementation Pooled Fund, TPF-5(255).

16. Abstract

This case study presents a safety analysis by the Federal Highway Administration, Western Federal Lands Highway 

Division (WFLHD) Highway Safety Team. The WFLHD used the Interactive Highway Safety Design Model (IHSDM) 

software as part of the design process for the rehabilitation of Yale-Kilgore Road. The Yale-Kilgore Road corridor is a 

county owned and operated two-lane undivided road located in Clark and Fremont counties in Idaho. The project corridor 

is an important recreational and commercial artery for the community. As a rural highway in and around a national forest, it 

has many unique challenges that may not exist in more urban and suburban environments. The Yale-Kilgore Road Safety 

and Traffic Assessment is a practical example of how the suite of IHSDM modules can support typical project development 

in an atypical context. Although the corridor is currently a mix of paved and unpaved surfaces, with speed and out-of-town 

traffic representing major concerns in both the present and the future, IHSDM assisted practitioners with the analysis 

tradeoffs necessary to make informed design and safety countermeasure decisions. The ability to analyze the corridor from 

a broad perspective (i.e., not crash prediction alone) allowed WFLHD to assess targeted improvements along the corridor, 

especially along segments of the corridor where the relative crash risk is highest.

17. Key Words: 

Rural, 2-lane, Undivided, Safety, IHSDM, 

Highway Safety Manual

18. Distribution Statement

No restrictions.

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this 

page) Unclassified

21. No. of Pages

 16

22. Price

Technical Documentation Page
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Acronyms

Acronym Description

AADT annual average daily traffic

AASHTO American Association of State Highway and Transportation Officials 

CPM Crash Prediction Module

DCM Design Consistency Module

DVM Driver/Vehicle Module

EB Empirical-Bayes 

FHWA Federal Highway Administration

FI fatal and injury

HSM Highway Safety Manual 

ID Idaho

IHSDM Interactive Highway Safety Design Model

ITD Idaho Transportation Department

mph miles per hour

PDO property damage only

PRM Policy Review Module

PS&E Plans, Specifications, and Estimates

TAM Traffic Analysis Module

WFLHD Western Federal Lands Highway Division
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Table of Contents

Introduction............................................................................................................................................... 1

Safety Performance Analysis ................................................................................................................... 2

Challenges.................................................................................................................................................. 8

Conclusions and Lessons Learned ........................................................................................................... 9

References ................................................................................................................................................ 10

List of Figures

Figure 1. Graphic. Yale-Kilgore Road project location.......................................................................... 1

Figure 2. Graphic. Yale-Kilgore Road segment groups. ........................................................................ 3

List of Tables

Table 1. Yale-Kilgore Road expected crash frequencies by year.......................................................... 5

Table 2. Comparison of expected and predicted crashes for the evaluation period.......................... 5

Table 3. Expected crash type distribution. ............................................................................................. 6

Table 4. Segment groups ranked by risk score. ..................................................................................... 7
 

SAFETY DATA CASE STUDY FHWA-SA-21-073

Executive Summary

This case study presents a safety analysis by the Federal Highway Administration, Western Federal Lands 

Highway Division (WFLHD) Highway Safety Team. The WFLHD used the Interactive Highway Safety Design 

Model (IHSDM) software as part of the design process for the rehabilitation of Yale-Kilgore Road. The YaleKilgore Road corridor is a county owned and operated two-lane undivided road located in Clark and Fremont 

counties in Idaho. The project corridor is an important recreational and commercial artery for the community. 

As a rural highway in and around a national forest, it has many unique challenges that may not exist in more 

urban and suburban environments. The Yale-Kilgore Road Safety and Traffic Assessment is a practical example 

of how the suite of IHSDM modules can support typical project development in an atypical context. Although 

the corridor is currently a mix of paved and unpaved surfaces, with speed and out-of-town traffic representing 

major concerns in both the present and the future, IHSDM assisted practitioners with the analysis tradeoffs 

necessary to make informed design and safety countermeasure decisions. The ability to analyze the corridor 

from a broad perspective (i.e., not crash prediction alone) allowed WFLHD to assess targeted improvements 

along the corridor, especially along segments of the corridor where the relative crash risk is highest.
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Introduction 

The Transportation Research Board’s Safety Performance and Analysis (ACS20) User Liaison 

Subcommittee has an on-going initiative focused on practical application of the American Association of 

State Highway and Transportation Officials (AASHTO) Highway Safety Manual (HSM) (i.e., “using the 

HSM in the real world”). The Federal Highway Administration (FHWA) also administers the HSM

Implementation Pooled Fund, which includes 22 States focused on projects to help further HSM 

implementation. Development of HSM case studies will assist practitioners in performing data-driven 

safety analysis using the advanced methods described in the HSM. The primary purpose of the HSM case 

studies is to highlight noteworthy applications of HSM methods, focus on common challenges, and 

feature agencies that overcame those challenges. These case studies serve as a source of lessons learned 

and noteworthy practices to help guide practitioners applying the HSM.

Background

This case study presents a safety analysis by the FHWA, Western Federal Lands Highway Division 

(WFLHD) Highway Safety Team. The WFLHD used the Interactive Highway Safety Design Model 

(IHSDM) software as part of the design process for the rehabilitation of Yale-Kilgore Road. Yale-Kilgore 

Road is a county owned and operated two-lane undivided road located in Clark and Fremont counties in

Idaho (ID). The western half of the corridor in Clark County is unpaved and transitions to paved asphalt 

at the county line with Fremont County. Although the road is county owned and operated, a substantial 

portion of the corridor falls within the Caribou-Targhee National Forest, and the eastern terminus of 

the corridor is less than 30 miles from an entrance to Yellowstone National Park.

Figure 1. Graphic. Yale-Kilgore Road project location.

© 2021 Google® © 2021 Maxar Technologies. Modified by the authors. 

Note: The white location pins and white dashed line were added by the authors to delineate the project bounds.
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Purpose and Need

Although the Yale-Kilgore Road project is primarily focused on rehabilitation, the corridor is expected 

to assume a more regionally important role in the near future. The western, unpaved portion of the 

corridor will be paved, and the entire corridor will become an increasingly important connection 

between I-15 near Spencer, ID and US 20 near Island Park, ID. With asphalt paving becoming necessary 

for future mobility along the corridor, WFLHD applied the IHSDM software to assess anticipated safety 

needs. The application of the IHSDM software allowed WFLHD to comprehensively analyze the 

corridor for safety and operational concerns during the project development process. The IHSDM

software contains five evaluation modules and an Economic Analysis Tool. WFLHD used the evaluation 

modules to assess future safety performance and make recommendations based on existing conditions, 

historical crash trends, and anticipated design changes to the corridor: 

1. Crash Prediction Module (CPM). 

2. Design Consistency Module (DCM). 

3. Policy Review Module (PRM). 

4. Traffic Analysis Module (TAM). 

5. Driver/Vehicle Module (DVM). 

Project Description

• Sponsoring agency: WFLHD.

• Project location: Clark County and Fremont County, ID.

• Project bounds and length of project: Yale-Kilgore Road from milepost 9.0 to milepost 

30.8 (21.8 miles).

• Facility type(s): 2-lane, undivided major collector.

• Area type: Rural, mountainous terrain.

• Project status (as of January 2021): Analysis completed based on a 30-percent plans, 

specifications, and estimate (PS&E) package submittal; begin construction in 2022. 

Safety Performance Analysis

This section provides an overview of the safety analysis methods, proposed alternatives, and final results.

Analysis Overview 

WFLHD obtained crash data from the Idaho Transportation Department’s (ITD’s) OpenData portal for 

all years between 2005 through 2018. The high number of years of crash data reflect the low frequency 

of crashes on the corridor. (Underreporting is a noted concern on rural, Federal Lands roads, and more 

years of crash data on low frequency roads better reflect long-term average frequency). The limited 

number of historical crashes emphasized the need for other modules of the IHSDM software to assess 

more nuanced risks. The project team linked crash data to the corridor by using associated mileposts 

and assigning project station equivalences for each location. The PS&E package submission for 30-

percent designs provided relevant traffic information. The PS&E package documented a base year (2015) 

annual average daily traffic (AADT) of 650 vehicles per day (7-percent truck traffic) and a future year 
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SAFETY DATA CASE STUDY FHWA-SA-21-073

(2035) AADT of 966 vehicles per day (12-percent truck traffic). The project team assumed a linear 

growth rate between 2015 and 2035 to estimate traffic for the construction year (2021) and design year 

(2041). For other design and roadside elements, the PS&E package contained normal cross slopes, 

typical sections provided shoulder widths, and the project team derived driveway density and roadside 

hazard rating (i.e., a 1-7 rating of roadside objects and the availability of recoverable space; Harwood et 

al., 2000) from aerial imagery. 

To begin the analysis, IHSDM segmented the study corridor based on changes in geometric 

characteristics (e.g., lane width, shoulder width, cross slope, roadside hazard rating), traffic data, and 

anticipated driver behavior. This identified 363 unique segments, and WFLHD aggregated these locations

into 18 distinct “groups” for easier output analysis and reporting (figure 2). 

The defining features of these segments include long tangents or a series of reverse curves. The project 

team used the TAM and DVM to help identify errors in data inputs, areas of high opposing speed 

differentials, and higher risk locations within the study area; the project team did not complete the 

remaining three modules until these two modules were run without error.

The project team used the IHSDM DVM and DCM to examine expected speeds throughout the 

corridor. These modules use geometric features, horizontal curves, and vertical grades to assess likely 

Figure 2. Graphic. Yale-Kilgore Road segment groups.

© 2019 Google® © 2019 Maxar Technologies. Modified by FHWA. 

Note: The yellow arrows and lines, number callout boxes, and red line were added by the WFLHD project team to 

delineate project extents and sections.
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SAFETY DATA CASE STUDY FHWA-SA-21-073

impacts on speed. The WFLHD analysts used a design speed of 45 miles per hour (mph). Since the 

project team lacked formal speed data, they used a desired free-flow speed of 55 mph due to long 

tangents and minimal variation in grade. The project team also assumed a “nominal” driver type, a 

“passenger car” vehicle type, and “long tangent” for driver road familiarity. Discrepancies between the

design speed and the expected speed (i.e., predicted as a result of horizontal curvature, vertical grade, 

or other design elements that lead to large changes in speed) highlight locations where speed 

countermeasures would be most appropriate.

WFLHD compared each of the 18 groups using the CPM, PRM, DVM, and DCM in IHSDM. The project 

team developed the following metrics for each group:

• An Empirical-Bayes (EB) analysis using historical crashes; this produced an estimate of expected 

crashes per group per mile.

• Predicted crashes using the default, uncalibrated CPM in IHSDM.

• A design consistency analysis that flagged differences between the design speed and expected 

speed based on the results from the TAM.

• A policy review flag for design elements that did not conform to the guidance of the AASHTO A 

Policy on Geometric Design of Highways and Streets or “Green Book” (2011) or deficient stoppingsight distance.

o WFLHD obtained surveyed horizontal and vertical alignments, used preliminary crosssection designs, and reviewed aerial imagery for vegetation or other fixed obstructions 

to support this analysis.

• An average lateral vehicle offset for both directions of travel; this DVM analysis assesses the 

difficulty with which vehicles are able to stay within a travel lane (e.g., side friction demand).

Crash Prediction Analysis & Results

WFLHD developed estimates for predicted crashes, as well as EB-derived expected crashes, based on 

the HSM’s default model values for two-lane, undivided rural roads. For the historical period between 

2005 and 2018, the study corridor averaged 3.1 total crashes and 0.6 fatal and injury (FI) crashes per 

year. WFLHD assumed a future paved condition along the entire corridor for the purposes of this 

analysis. Table 1 summarizes the results of the CPM analysis for each year in the study period (2021-

2041). Over 30 percent of all expected crashes were FI crashes with the remaining crashes being 

property damage only (PDO); this is the default distribution from the predictive method, and it is 

constant throughout the study period. 
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Table 1. Yale-Kilgore Road expected crash frequencies by year. 

Year Total

Crashes 

FI

Crashes 

Percent 

FI

(%)

PDO 

Crashes 

Percent 

PDO 

(%)

2021 4.33 1.35 31.188 2.98 68.812

2022 4.43 1.38 31.188 3.05 68.812

2023 4.52 1.41 31.188 3.11 68.812

2024 4.62 1.44 31.188 3.18 68.812

2025 4.72 1.47 31.188 3.25 68.812

2026 4.82 1.5 31.188 3.31 68.812

2027 4.92 1.53 31.188 3.38 68.812

2028 5.01 1.56 31.188 3.45 68.812

2029 5.11 1.59 31.188 3.51 68.812

2030 5.21 1.62 31.188 3.58 68.812

2031 5.31 1.66 31.188 3.65 68.812

2032 5.41 1.69 31.188 3.72 68.812

2033 5.5 1.72 31.188 3.78 68.812

2034 5.6 1.75 31.188 3.85 68.812

2035 5.7 1.78 31.188 3.92 68.812

2036 5.8 1.81 31.188 3.99 68.812

2037 5.9 1.84 31.188 4.06 68.812

2038 6 1.87 31.188 4.13 68.812

2039 6.1 1.9 31.188 4.2 68.812

2040 6.2 1.93 31.188 4.27 68.812

2041 6.3 1.97 31.188 4.34 68.812

Total 111.48 34.77 31.188 76.71 68.812 

Table 2 compares the results of the expected and predicted crash analyses. The comparison indicated 

that more crashes are predicted based on the HSM predictive methodology than are expected based on 

the available historical crash data and the application of the EB method. Table 3 shows the distribution 

of expected crash types. The largest expected crash type involved single vehicle, run-off-road crashes.

Table 2. Comparison of expected and predicted crashes for the evaluation period. 

Scope Total 

Crashes 

FI 

Crashes 

Percent 

FI (%)

PDO 

Crashes 

Percent 

PDO (%)

Predicted 129.55 41.59 32.10 87.97 67.90

Expected 111.48 34.77 31.19 76.71 68.81

Expected - Predicted -18.07 -6.82 n/a -11.25 n/a

Percent Difference -16.21 -19.61 n/a -14.67 n/a

Note: n/a = not applicable. 
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Table 3. Expected crash type distribution. 

Crash Type

Single/ 

MultiVehicle

FI 

Crashes 

FI 

Crashes 

(%)

PDO 

Crashes 

PDO 

Crashes 

(%)

Total 

Crashes 

Total 

Crashes 

(%)

Collision with 

Animal Single 1.3 1.2 14.1 12.7 13.5 12.1

Collision with 

Bicycle Single 0.1 0.1 0.1 0.1 0.22 0.2

Other Singlevehicle Collision Single 0.2 0.2 2.2 2.0 2.3 2.1

Overturned Single 1.3 1.2 1.2 1.0 2.8 2.5

Collision with 

Pedestrian Single 0.2 0.2 0.1 0.1 0.3 0.3

Run Off Road Single 19.0 17.0 38.7 34.8 58.1 52.1

Right-Angle 

Collision Multi- 3.5 3.1 5.5 5.0 9.5 8.5

Head-on 

Collision Multi- 1.2 1.1 0.2 0.2 1.8 1.6

Other Multivehicle Collision Multi- 0.9 0.8 2.3 2.1 3.0 2.7

Rear-end 

Collision Multi- 5.7 5.1 9.4 8.4 15.8 14.2

Sideswipe Multi- 1.3 1.2 2.9 2.6 4.1 3.7

Total Crashes n/a 34.8 31.2 76.7 68.8 111.5 100 

Note: n/a = not applicable. 

Although the analysis predicts more crashes per year than the number of reported crashes between 

2005 and 2018, the project team noted that this annual increase is likely the result of projected traffic 

growth on the corridor. The project team also noted that increased speeds, as a result of paving

currently unpaved roads, could potentially lead to a higher baseline for crash frequency in addition to 

higher traffic volumes.

It is important to note that WFLHD used the IHSDM CPM results as just one component of its overall 

assessment of the corridor, and the project team applied the predicted, non-EB crash results as part of 

the final overall assessment. There are important considerations and trade-offs when using the crash 

prediction methodology in the HSM, and these are compared with the Yale-Kilgore Road project team’s 

assumptions in the Challenges section of this case study. 
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SAFETY DATA CASE STUDY FHWA-SA-21-073

Documentation and Use of Analysis Results

Using the aforementioned comparison metrics, the project team devised a scoring system to rank the 18

groups. For each metric, the project team assigned:

• One point to groups scoring in the 90th percentile (e.g., a segment group had a predicted and

expected per-mile crash rate greater than 90 percent of all groups). 

• One-half point to groups scoring between the 75th and 90th percentiles. 

• Zero points to groups scoring below the 75th percentile.

This comparison highlighted five groups for closer consideration, Groups 14, 13, 1, 7, and 18 (table 4).

Although Group 18 scored lower than the highest four and scored similarly to other groups, the project 

team included it for its history of recorded crashes.

Table 4. Segment groups ranked by risk score.

Rank Group Cumulative Risk 

Score Start (Station) End (Station)

1 14 3 876+63.81 950+00.00

2 13 2.5 825+46.46 876+63.81

3 1 2 10+00.00 36+83.43

3 7 2 570+19.81 581+09.88

5 18 1.5 1126+00.00 1140+89.50

5 2 1.5 36+83.43 259+00.00

5 8 1.5 581+09.88 637+19.92

5 11 1.5 756+85.00 790+00.00

9 4 1 295+00.00 364+77.78

9 5 1 364+77.78 380+00.00

9 9 1 637+19.92 701+00.00

9 15 1 950+00.00 1006+09.77

13 3 0.5 259+00.00 295+00.00

13 6 0.5 380+00.00 570+19.81

13 10 0.5 701+00.00 756+85.00

13 12 0.5 790+00.00 825+46.46

13 16 0.5 1006+09.77 1053+99.78

13 17 0.5 1053+99.78 1126+00.00

WFLHD has an agency-specific Crash Reduction Factor Calculation Spreadsheet that the agency uses to 

assess potential benefits with respect to specific treatments; this tool mirrors a common crash 

modification factor application. The project team applied the treatments and crash reduction factors 

available in the Crash Reduction Factor Calculation Spreadsheet to predicted crashes for the entire 

corridor, with the top 5 high-risk groups in table 4, (14, 13, 1, 7, and 18) receiving special consideration. 
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SAFETY DATA CASE STUDY FHWA-SA-21-073

The project team recommended several potential treatments based on the cumulative design flags, crash 

predictions in IHSDM, and the results of the Crash Reduction Factor Calculation Spreadsheet. The 

recommendations included:

 Replace all existing regulatory and warning signs.

 Increase enforcement and increase regulatory signage for speeding concerns.

 Convert the roadway surface from dirt/gravel to asphalt (with additional 2-ft paved shoulder). 

 Use safety edge.

 Stripe or restripe all centerlines and edge lines to wet reflective pavement markings. 

 Add or replace post-mounted delineators where necessary, especially on curves.

 Consider typical project clearing limits to remove trees and smaller vegetation within the 

roadside.

 Add guardrail in high-risk groups, especially at bridges and culverts.

 Flatten side slopes in combination with other warning signage, delineators, clear zone, and 

guardrail installations. 

Since roadway departure and speed were key concerns during the corridor assessment (table 3), 

WFLHD noted in the analysis documentation specifically how these countermeasures could potentially 

reduce crashes, as well as how the existing conditions in each high-risk group could be targeted by the 

suite of recommended countermeasures. Based on the current design, the WFLHD project team

estimated that these countermeasures could reduce crashes over the entire corridor by approximately 

35 percent over the project’s design life.

Challenges

Although the EB method is a way to account for regression-to-the-mean bias in future crash predictions, 

there are a few important caveats that could apply to a context similar to the Yale-Kilgore corridor:

1. The HSM predictive methods, and associated EB method, do not necessarily apply to unpaved 

roads; however, the Yale-Kilgore analysis only applied the predictive methods to an assumed 

paved condition in the future.

2. As a general rule, practitioners should not apply the EB method to an uncalibrated model; this 

could lead to significant bias in the results.

3. If a corridor is expected to experience significant operational and geometric changes in the 

future (e.g., converting an unpaved facility to a paved facility), the EB method should not be used 

to directly compare a “Build” scenario with a “No-Build” scenario.

Although these are important considerations when applying the predictive method, WFLHD used the 

CPM results as one component to supplement its more detailed safety assessment. WFLHD noted that 

the analysis did not compare the Build scenario with a potential No-Build scenario, and the project team

did not use the analysis as a justification for the project. The results served to help assess potential risks 

along the corridor and identify appropriate countermeasures, complementary to the other IHSDM 

modules. The HSM contains more information regarding the application of predictive methods and the 

appropriateness of the EB method.
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SAFETY DATA CASE STUDY FHWA-SA-21-073

The IHSDM software provides a platform for safety analysts and engineers to assess the cumulative 

impact of various safety design and policy decisions. However, many of the inputs in the IHSDM modules 

are subject to engineering judgment, and the software may not be applicable for all circumstances 

(e.g., unpaved roads). For instance, the practitioner must assess the roadside hazard rating based on 

input criteria and professional judgment. Furthermore, the software can flag design deficiencies or assist 

with the tradeoffs associated with various elements, such as sight distances, clear zones, side slopes, and 

cross slopes, but the optimal solutions may not be feasible at every candidate location. In these 

circumstances, the practitioner can assess and outline potential improvements where possible. The 

WFLHD project team noted the order of preferential countermeasures (e.g., install/upgrade guardrail;

flatten side slopes; and install curve delineators and warning signage) based on the availability of clear 

zone. In more extreme circumstances, tree removal to improve sight distance or widen clear zone could

destabilize a slope (particularly on the inside of horizontal curves on Group 13). In these circumstances, 

the project team recommended vegetation trimming alone.

Conclusions and Lessons Learned

The Yale-Kilgore Road project corridor is an important recreational and commercial artery for the 

community. As a rural highway in and around a national forest, it has many unique challenges that may 

not exist in more urban and suburban environments. The Yale-Kilgore Road Safety and Traffic Assessment is 

a practical example of how the suite of IHSDM modules can support typical project development in an 

atypical context (WFLHD, 2020). Although the corridor is currently a mix of paved and unpaved 

surfaces, with speed and out-of-town traffic representing major concerns in both the present and the 

future, IHSDM assisted practitioners with the tradeoffs necessary to make informed design and safety 

countermeasure decisions. The ability to analyze the corridor from a broad perspective (i.e., not crash 

prediction alone) allowed WFLHD to assess targeted improvements along the corridor, especially along 

segments of the corridor where the relative crash risk is highest.
10

References

 American Association of State Highway and Transportation Officials. (2010). Highway Safety 

Manual: 1st Edition, Washington, D.C. Resources available online: 

http://www.highwaysafetymanual.org/Pages/default.aspx.

 American Association of State Highway and Transportation Officials. (2011). A Policy on 

Geometric Design of Highways and Streets: 6th Edition, Washington, D.C.

 Federal Highway Administration. (2021a). “CMF Clearinghouse” (website). Available online: 

http://www.cmfclearinghouse.org/index.cfm. 

 Federal Highway Administration. (2021b). “Interactive Highway Safety Design Model” 

(website). Available online: https://highways.dot.gov/research/safety/interactive-highway-safetydesign-model/interactive-highway-safety-design-model.

 Harwood, D.W., Council, F.M., Hauer, E., Hughes, W.E., Vogt, A. (2000). Prediction of the 

Expected Safety Performance of Rural Two-Lane Highways, FHWA-RD-99-207, Washington, D.C.

Available online: https://www.fhwa.dot.gov/publications/research/safety/99207/99207.pdf. 

 Western Federal Lands Highway Division. (2020). ID Clark 6805(1) Yale-Kilgore Road Safety and 

Traffic Assessment, Vancouver, WA. Project website available online: 

https://highways.dot.gov/federal-lands/projects/id/clark-6805-1. 

Contact

FHWA Western Federal Lands Highway Division

Sean Kilmartin, Highway Safety Engineer

sean.kilmartin@dot.gov

Matthew Hinshaw, Highway Safety Engineer

matthew.hinshaw@dot.gov