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SAFETY ASSESSMENT

For

NFSR 708 Fossil Creek Road

Coconino National Forest, Arizona

PREPARED FOR

UNITED STATES FOREST SERVICE REGION 3

Prepared by

Federal Highway Administration (FHWA)

Central Federal Lands Highway Division (CFLHD)

12/07/2016
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Table of Contents

I. Executive Summary

II. Introduction

III. NFSR 708 Safety Assessment

IV. Conclusions and Recommendations

V. References

VI. Appendices

A. Driving Log/Issues and Proposed Mitigation

B. Site Photos

C. Maintaining Traffic Sign Retroreflectivity

D. Roadside Treatments

E. W-Beam Guardrail Standards

F. Aesthetic Guardrails

G. Preliminary Existing Road Surface Investigation and Recommendations -

Technical Memorandum
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I. Executive Summary

The United States Forest Service (USFS) Region 3 contacted Central Federal Lands to conduct a

Safety Assessment along National Forest System NFSR 708 (NFSR 708) in the Coconino

National Forest. NFSR 708 is a popular road for day-use and camping, and was chosen for an

assessment due to the severe washboarding, pedestrian and vehicle conflicts, and driver behavior.

In addition to the safety assessment, a surfacing study was performed to provide potential

solutions for the washboarding. Projected traffic data reveals that there are approximately 316 

vehicles per day; however, during peak seasonal times the volume can be as high as 1,000 

vehicles per day.

There have been 59 crashes reported on the road from July, 2006 to April, 2016. Of the total

crashes, 37 (63%) were property damage only crashes, and 22 (37%) crashes resulted in at least

one injury. Single vehicle run-off-road (ROR) type crashes were indicated in 28 of the total

crashes, of which 15 resulted in an injury. Multiple vehicles were reported in 14 of the crashes,

of which 2 resulted in an injury. Not all of the crash reports noted driver behavior; however, 14

of the crash reports indicated that speeding was the main contributing factor to the crash.

Based on Engineering, Enforcement, Education, and Emergency response (4E’s of Safety),

short-term improvements include upgrading all signs to current MUTCD requirements,

providing a consistent clear zone wherever practical, providing adequate sight distance along

curves, and partnering with Yavapai County to maintain a crash database. Long-term

improvements include upgrading the existing bridge railing, installing guardrail and end

terminals, and resurfacing the road.

This publication identifies possible safety improvement recommendations along with a

preliminary cost estimate for short-term and long-term improvements. The conclusions and

recommendations in this report are to be used as a guide.
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II. Introduction

The United States Forest Service (USFS) Region 3 contacted Central Federal Lands to conduct a

Safety Assessment along National Forest System NFSR 708 (NFSR 708) in the Coconino

National Forest (see Figure 1). NFSR 708 (Fossil Creek Road) is accessed off of Arizona State

Highway 260 (SH 260) approximately 7 miles east of Camp Verde, Arizona (see Figure 2).

NFSR 708 also extends into the Tonto National Forest, but that section of the road is currently

closed due to rockfall issues. Unlike the Tonto National Forest, Coconino National Forest has

fairly stable rock slopes.

NFSR 708 is a bedrock and gravel road which connects SH 260 with Tonto National Forest. The

study area includes 15.8 miles along NFSR 708 from the intersection with SH 260 to the bridge at

Fossil Creek.

The road is classified as an ML-3, but due to the road surface conditions the actual maintenance

level is more similar to a ML-2. The Forest performs maintenance through force accounts. The

climate is generally dry with frequent rainfall and flooding from July through September. The

area does not receive any measurable snowfall.

NFSR 708 is a popular road for day-use and camping. Many of the visitors are coming from the

Phoenix area. Forest personnel reported that there is no bicycle use on the road, but pedestrians

use to the road to access the swimming sites at Fossil Creek. Passenger cars, pickup trucks, and

SUVs are frequently seen along the road. Due to the severe washboarding, motorcycles, campers,

and RVs are not common on the road. Occasionally, large utility company vehicles use the road

to access the power plant on NFSR 502 (Childs Road).

Utilities include overhead electric near Childs Road and an underground fiber optic line along

the entire study area. The fiber optic line is generally on the west side of the road, but frequently

crosses under the road. The fiber optic is a concern because it is buried only 2’-4’ and many of

the needed drainage and cattleguard improvements are not feasible due to the shallow depth of

the utility.

Safety Assessments provide as many pertinent improvement recommendations as possible, but

unique conditions within the Forest, including environment, wildlife, and visitor experience must

be taken into account when considering any of the recommendations. The conclusions and

recommendations in this report are to be used as a guide.
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Figure 1. Arizona map

Coconino 

National 

Forest
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Figure 2. NFSR 708 To Strawberry, AZ

To Camp Verde, AZ

MP 1.1 NFSR 

708 - NFSR 500 

Intersection

MP 0.0 Begin 

NFSR 708 at 

SH 260

Approximate location 

of traffic counter

MP 14.2 NFSR 

708 – NFSR 502 

Intersection

Approximate 

location of 

traffic counter

MP 15.8 End 

NFSR 708
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The Safety Assessment was conducted June 7, 2016, and included an office meeting and a

field review. The office meeting provided for a discussion of the observations along NFSR

708, including speeding, washboarding, sharp horizontal curves, signing, narrow roadway

template, and steep roadway grades. The following were in attendance:

Jennifer Dean Assistant Regional Transportation Engineer USFS Region 3

Lance Haubrick Civil Engineer USFS Region 3

Barbara Burke Highway Safety Engineer FHWA-CFLHD

Traffic Data

The USFS provided traffic volume counts obtained during a 19-day study period from July 15,

2011 to August 2, 2011. This time period is fairly representative of the highest-use time of year.

Two counters were placed on Fossil Creek Road (see Figure 2). One counter was placed at

approximate MP 0.5 near NFSR 500. The second counter was placed on Fossil Creek Road

approximately one-half mile east of the intersection of NFSR 502 and NFSR 708 in the Tonto

National Forest. The counter at MP 0.5 recorded 3,562 vehicles, and the counter in the Tonto

National Forest recorded 7,326 vehicles.

A portion of Fossil Creek Road in the Tonto National Forest is now closed and traffic is no

longer coming from the town of Strawberry, AZ. For this report, the traffic counts are averaged

to best represent traffic conditions. The total count is 10,888 vehicles for the 19-day period in

2011 and the average is 5,444 vehicles. The Average Daily Traffic (ADT) for the 19-day period

is 287 vehicles per day (vpd). Using a 2% annual growth rate, the 2016 ADT is projected to be

approximately 316 vpd. However, Forest personnel reported that during the peak camping

season, the traffic volumes can approach 1,000 vehicles on any given day.

Crash Data

Typically, crashes are analyzed from law enforcement crash reports which indicate crash severity,

crash type, driver behavior, location, object struck, driver citation, time of day, weather, road

surface conditions, etc. The data can then be used to determine “hot spot” locations and common

crash characteristics and conditions. It should be noted that not all crashes are reported. This is 

especially true for Property Damage Only (PDO) crashes when no law enforcement officers or

towing services are called to the scene.

Coconino National Forest obtained crash data from Yavapai County Law Enforcement which

covered an approximate 10-year period of time from 7-15-06 to 4-24-16. The crash data is in the

form of a narrative description, and as such it was not possible to identify all of the crash

characteristics for each crash. For example, there were no latitude/longitude coordinates to
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locate the crashes. Weather (rain, clear, fog), road geometry (curve, tangent), road conditions

(dry, wet, muddy), driver behavior (speeding, inattention, impaired), object struck (tree, rock,

ditch), and driver citation (failure to control, DUI) were noted in less than half of the crash

narratives. However, data is available for annual distribution, time of day, single and multiple

vehicles, crash severity (PDO, Injury), and crash type (ROR, rollover, head-on, sideswipe), and

can be analyzed for all crashes.

From the available information in the crash narratives, there are several factors which can be

analyzed. During the10-year period, there were 59 reported crashes on NFSR 708. Crash

distribution indicates that 2015 had the highest number of crashes comprised of 5 Property

Damage Only (PDO) and 6 Injury crashes. See Figure 3.

Figure 3. Crash Distribution

Crash severity was noted in all of the crash narratives. Of the total reported crashes there were 37

(63%) Property Damage Only (PDO) and 22 (37%) Injury crashes. There were no Fatal crashes.

See Figure 4.

0

1

2

3

4

5

6

7

8

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

PDO

Injury
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Figure 4. Crash Severity

Time of day was noted in all of the crash narratives. During the period from Midnight to 6 am

there were 2 crashes (3% of the total). From 6 am to Noon, there were 8 crashes (14%). From

Noon to 6 pm there were 29 crashes (49% of the total). From 6 pm to Midnight there were 20

crashes (34%). The high percentage of mid-day (Noon-6 pm) crashes is consistent with the dayuse characteristic of NFSR 708. See Figure 5.

Figure 5. Time of Day

Property 

Damage Only

63%

Injury

37%

35

30

25

20

15

10

5

0

Midnight-6 am 6 am - Noon Noon-6 pm 6 Pm - Midnight
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The number of vehicles was noted in all of the crash narratives. Of the total crashes, 45 (76%)

were single vehicle crashes and 14 (24%) were multiple vehicle crashes. Of the 45 single vehicle

crashes, 29 (64%) were ROR, either to the left or to the right. Rollover crashes account for 4 (9%) 

of the single vehicle crashes. As stated earlier, not all of the data fields were described in the

narrative. As such, there were 12 single vehicle crashes (27%) that were not described as to crash

type. See Figure 6.

Figure 6. Single Vehicle Crash Type

Of the 14 multiple vehicle crashes, 6 (43%) were head-on crashes, 5 (36%) were sideswipe

crashes, 1 (7%) was a rear end crash in a parking area, and 2 (14%) were not categorized. See

Figure 7.

ROR

64%

Rollover

9%

Unknown

27%
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Figure 7. Multiple Vehicle Crash Type

The crash narratives provided partial information on road geometry, objects struck, driver

behavior, and driver citation. Of the 59 crashes, 17 crashes (29%) listed horizontal curves, 4

crashes (7%) listed vertical curves, and 3 crashes (5%) listed Tangent/On-Grade. Thirty-five

crashes (59%) did not have geometry noted in the crash narrative. See Figure 8.

Figure 8. Road Geometry

Of the 59 crashes, the crash narratives provide information on single vehicle object struck for

39% of the crashes. The most common object struck by a single vehicle is the embankment,

Horizontal 

Curve

29%

Vertical Curve

7%

Tangent/OnGrade

5%

Unknown

59%

Unknown

14%

Rear End

7%

Head on

43%

Sideswipe

36%
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reported in 14 (24%) of the total crashes. A single vehicle striking a ditch was reported in 4

crashes (7%). A single vehicle striking a rock or tree was reported in 5% and 3% of the total

crashes, respectively. See Figure 9.

Figure 9. Single Vehicle Object Struck

Of the 59 crashes, the crash narratives provided information on the driver behavior in 29% of the

total crashes. Fourteen crashes (24%) listed speeding as a driver behavior factor in the crash.

Impaired driving was noted in 2 (3%) of the 59 crashes. Inattention was noted in 1 crash (2%).

See Figure 10.

Figure 10. Driver Behavior

Embankment

24%

Ditch

7%

Rock

5%

Tree

3%

Unknown

61%

Speeding

24%

Impaired

3%

Unknown

71%

Inattention

2%
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Of the 59 crashes, the crash narratives provided information on the driver citation in 22% of the

total crashes. Failure to control vehicle was cited in 8 crashes (13%). Driving Under the

Influence (DUI) was cited in 3 crashes (5%). Reckless Driving was cited in 1 crash (2%). See

Figure 11.

Figure 11. Driver Citation

To summarize, the crash narratives provide complete data for annual distribution, crash severity,

time of day, number of vehicles, and crash type. However, other crash characteristics such as

road geometry, road condition, object struck, driver behavior, and driver citation are not a

complete data set. Even though there are gaps in the data set, there are some conclusions that

can be provided based on the known crash characteristics:

• 36% horizontal and vertical curve-related crashes is consistent with the numerous sharp

curves seen along the entire route,

• 24% speeding is consistent with the Forest personnel’s description of speeding issues

along the route,

• 31% single vehicle ROR and striking the embankment or ditch is consistent with the

numerous steep fill and cut slopes, and

• 79% multiple vehicle head-on and sideswipe crashes is consistent with the narrowness of

the roadway template.

Failure to

Control Vehicle

13%

DUI

5%

Reckless Driving

2%

Unknown/No

citation

78%

Disorderly

Conduct

2%
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III. NFSR 708 Safety Assessment

During the field review there were several safety concerns that were either witnessed or

described by Forest personnel. The concerns include:

• Severe washboarding

• Speeding

• Horizontal curves with limited sight distance due to slopes and vegetation

• Narrow roadway template with no recoverable foreslope

• Steep cut and fill slopes

• Sign damage and vandalism

• Sign post installation

• Too many signs is an issue for Forest maintenance

• Pedestrians walking along the narrow road

Refer to Appendix A for the Driving Log with issues and proposed mitigation measures.

Road Conditions

The terrain is rugged and the road surface material is composed of bedrock and aggregate (see

Photo 1). During the field review, several measurements were taken at various locations.

Generally, the road measured 15’-21’ in width, with an average width of 19’. The ditches are 2’-

6’ in width and 1’-4’ in depth. The road is bladed on a 1-2 year cycle. There are steep cut and fill

slopes with numerous horizontal and vertical curves. There is a section of the road near MP 10.5 

which has a very steep vertical grade (12%-14%). Falling rock does occur, but the rocks are

normally less than 1’ in diameter, and are usually trapped in the deep ditches (see Photo 2).
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Photo 1. Terrain Characteristics

Photo 2. Typical rockfall in ditches

Washboarding is an issue, partially due to very little depth of aggregate over the bedrock.

Washboarding is typically 2”-4” deep and is prevalent throughout the alignment. See Photo 3.

Many fractured boulders protrude out of the roadway surface making travel difficult for a
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passenger car. Recently, the Forest Service placed millings mixed with aggregate in order to

stabilize the material and reduce washboarding near MP 4.0. See Appendix G for a summary of

surface conditions and recommendations.

Photo 3. Severe washboarding

Structures

There are two Low Water Crossings (LWC) along the road (MP 7.7 and MP 7.9). Photos 4 and 5

show the two LWCs.
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Photo 4. MP 7.7 Low Water Crossing

Photo 5. MP 7.9 Low Water Crossing

There are numerous drainage crossings, most of which are either dual, or single, corrugated

metal pipe (CMP). Frequently, there is significant erosion at the inlet and outlet of the culverts.

See Photo 6.
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Photo 6. Typical dual CMP installation with significant erosion

Also there are three concrete box culverts structures with headwalls and wingwalls (MP 1.3, MP

1.6, and MP 5.2). See Appendix G for additional discussion of the culverts. Two of the structures

have metal tube railing; however, the railing is not NCHRP 350 or MASH (Manual for Assessing

Safety Hardware) crashworthy. The concrete box culvert at MP 1.6 has significant erosion at the

wingwall. All of the concrete box culverts have OM3 object markers at the four corners. See

Photos 7-11.

Photos 7 and 8. Structure at MP 1.3
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Photos 9 and 10. Structure at MP 1.6

Photo 11. Structure at MP 5.2

There are approximately 7 cattleguards on the route (MP 0.0, MP 1.0, MP 4.8, MP 7.9, MP 10.4,

MP 14.6, and MP 15.3 ). Generally the cattleguards are 16’-18’ in width. See Photos 12 and 13.
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Photos 12 and 13. Typical cattleguard installations

Pullouts, Parking and Campgrounds

There are very few pullouts and parking areas along the road. Many visitors use the large parking

area at MP 0.0 (see Photo 14). Photo 15 shows a pullout at MP 9.8. Since there are so few

pullouts on the narrow road template, drivers have difficulty passing one another.

Photo 14. Parking area at MP 0.0
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Photo 15. Typical Pullout at MP 9.8

There are a few dispersed camping areas along the route. Photo 16 shows a typical campsite.

Photo 16. Dispersed Campsite at MP 7.8
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Visitors who wish to access the swimming holes at Fossil Creek use the small parking areas

adjacent to the road. These small parking areas fill up quickly, which results in vehicles being

parked along the roadside. See Photo 17. Pedestrians must exit their vehicles and walk along the

road. See Photos 18 and 19.

Photo 17. Parking along the road

Photos 18 and 19. Pedestrians walking along the road

To control the high-use periods, the Forest has initiated a lottery system for reserving a

campground. Once the campground area is filled to capacity, reservations are discontinued. This

has proven to help relieved some of the vehicle congestion on the road. Photo 20 shows the

checkpoint area at NFSR 502 (Childs Road) where visitors must show their lottery verification.
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Photo 20. Gated camping checkpoint area at NFSR 502

Signs

In October 2005, a features study including existing signs was conducted for the Forest Service.

Based on the recommendations in the study, Forest maintenance personnel have installed curve

warning signs, Chevron signs, object markers, and delineators to mark hazards. Object markers

are located at the structures, culverts, and cattleguards. See Photos 21 and 22.

Photos 21 and 22. Typical object markers at cattleguard and culvert

Some of the existing warning signs (curves, rough road) are damaged or have reduced

retroreflectivity (Photos 23 and 24).
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Photo 23. Damaged sign

Photo 24. Reduced retroreflectivity on sign MP 0.6
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The Forest uses U-channel sign posts. The terrain is too rocky to install carsonite posts.

Maintenance crews will use U-channel sections to raise the sign to the desired height by

telescoping the U-channel sections. See Photo 25.

Photo 25. Typical U-channel post installation

Typically, the maintenance crews place advance warning signs for LWCs and cattleguards, but

only if there is reduced sight distance from a horizontal or vertical curve. See Photo 26.
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Photo 26. Advance warning signs for LWC and cattleguard

Driver Behavior

Many visitors are coming from the Phoenix area and as such, they may be driving passenger

vehicles with limited axle clearance. Since the road is very narrow in many places, drivers tend

to drive along the centerline. When encountering on-coming traffic, drivers quickly move to the

edge of roadway, or come to a complete stop to allow the on-coming vehicle to pass.

Although speeding was mentioned as an issue on the road, speeding was not observed during the

field review. However, field observations of tracks in the aggregate reveal that vehicles do fishtail

which can be an indicator of speeding.

During the field review, driver speeds ranged from 5-10 mph. However, Forest personnel

reported that after blading operations and in the tangent sections of road where washboarding is

not as severe, drivers tend to increase their speed to 25-40 mph.

There is no cell phone coverage along the road; and as such, people frequently leave the scene of

a crash and drive or walk to the SH 260 intersection in order to notify law enforcement and

emergency personnel.
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IV. Conclusions and Recommendations

The Safety Assessment considered the 4Es (Engineering, Enforcement, Education, and

Emergency Response) when reviewing road characteristics, driver behavior, road users, and

crash information for recommending safety improvements.

• Engineering includes horizontal and vertical design, clear zone establishment, signing

and striping, vehicle types, road users, road surface, right-of-way, and the environment.

• Enforcement includes enforcement of traffic laws and regulations and any law

enforcement personnel actions at the scene of an incident (vehicle and non-vehicle

related).

• Education encompasses the dissemination of information to the road users through

programs and media.

• Emergency Response (EMS) includes the procedure and critical timing for response to

an incident.

NFSR 708 is a good example of the complicated interaction between human factors (speeding,

pedestrian use), vehicle types (passenger cars, pickup trucks, SUVs), and road conditions (steep

cut/fill slopes, limited sight distance, severe washboarding, sharp curves, fixed objects near the

edge of road). Therefore, the Assessment followed a six-step process to mitigate the potential

for crashes: Identify Sites, Characterize the Experience, Characterize the Conditions, Identify

Countermeasures, Select Appropriate Countermeasure, and Evaluate the Countermeasure. See

Figure 12.
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Figure 12. Six Step Process

Source: FHWA-NHI-380083

Engineering

Horizontal and Vertical Curves

As mentioned previously, there are curves with limited sight distance due to slopes and

vegetation. While it may not be practical for the Forest to scale back the cut slopes, the

vegetation can be managed through regularly scheduled brushing and clearing operations. Of

course, vegetation plays a vital role in providing habitat protection for the animal population, and

for erosion control on the steep fill slopes; therefore, total removal of all vegetation is not

recommended.

Clear Zone Establishment

“Clear Zone” is the term used to designate the unobstructed, traversable area provided beyond the

edge of the traveled way for the recovery of errant vehicles. NFSR 708 has several locations

where there is very little traversable/recoverable slope area, especially in the cut and fill sections.
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Based on the traffic data compiled from July 15, 2011 to August 2, 2011, the current Average

Daily Traffic (ADT) is approximately 316 vehicles per day (vpd). The AASHTO Roadside

Design Guide (RDG)1 indicates that for a road with a design speed of less than or equal to 40

mph, and an ADT of <750 vpd, a 7’-10’ clear area is recommended with slopes flatter than

1V:4H (RDG, Table 3-1). The RDG recognizes that it is not always practical to provide 7’-10’

of clear area due to terrain and environmental constraints. As a result, the AASHTO Guidelines

for Geometric Design of Very Low-Volume Local Roads (ADT </= 400)2 (VLVLRR) can be

used for roads such as NFSR 708. The VLVLRR guidelines indicate that a 6’ clear area should

be considered if social and environmental impacts can be kept to a minimum. Where constraints

of terrain and environment make a 6’ clear area impractical, recovery areas less than 6’ can be

used, including designs with 0’ clear area.

In order to balance the clear area distance with the terrain and environmental constraints and the

need to reduce ROR crashes, a consistent 3’ minimum clear area is recommended for NFSR 708.

In specific areas where the 3’ minimum cannot be met, additional delineation and/or shielding of

hazards should be considered as a potential mitigation.

Signs

The Forest has done a good job of installing signs which meet current minimum retroreflectivity

requirements. The few existing signs which do not meet the minimum retroreflectivity should be

replaced to ensure that the retroreflectivity meets current MUTCD3 Section 2A.08 standards.

See Appendix C for additional information. Regulatory and Warning sign panels should be

mounted so that the bottom of the panel is a minimum of 5’ above the road surface. When

pedestrians are frequently walking along the edge of road, the minimum panel height is 7’ above

the road surface.

The practice of splicing the U-channel sign post is appropriate; however, there are many sign

posts with the splice located 2’-4’ above the ground surface (see Photo 25). Crash testing of

several U-channel sign post makes/models reveals that the height of the exposed portion of the

splice must not be greater than 4” above the finished ground. If the splice is higher than 4” it

could snag the vehicle’s wheels and bumpers. All sign posts with the raised splice should be

replaced with break-away connections at the base of the post. There are several U-channel post 

products on the market which have been crash tested. The steel posts are sized at 2-4 lb/lf (avg. 3 

lb/lf) with ASTM A354 Grade BD bolts, or equivalent. Splice lengths and the use of spacers vary

by manufacturer. See Appendix D.

The Forest is commended for their efforts to install Object Markers (OM2 and OM3) to denote a

hazard (culverts and bridge structures) near the edge of traveled way. Object Markers (OM2 and

OM3) should be installed so that the bottom of the sign panel is approximately 4’ above the near
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edge of roadway. The nearest vertical edge of the panel should be flush with the near edge of the

hazard.

Installing a Type 1 Delineators on the outside of sharp horizontal curves and along steep fill

areas with limited clear zone can be an appropriate means to provide visual guidance to

motorists, especially in low-light and dark conditions.

Delineators should be installed so that the bottom-most reflective device (round or rectangular) is

approximately 4 feet above the near edge of roadway. Delineators can be installed with two

identical retroreflective devices oriented toward each direction of travel. This back-to-back

method of installation will provide the visual clues to drivers, and ensure a minimum amount of

signs. The delineators should be installed at a constant distance from the roadway edge. The

MUTCD indicates that delineators should be placed 2’ to 8’ outside the shoulder edge. On tangent

sections with steep fill slopes, given the low speed of the road, the delineators could be spaced at

200’ intervals. On curve sections, the delineators are spaced based on radii. For NFSR 708, the

curve radii ranges from 50’ to over 1,000’, which equates to a delineator spacing of 20’ to over 

90’. See Appendix D.

One mitigation strategy that is commonly used on roads with limited sight distance, sharp

horizontal and vertical curves, high pedestrian use, etc. is the use of flashing beacons on the

warning signs which helps to gain the drivers attention. However, due to the high incidence of

vandalism along NFSR 708, improvements to signs with solar-powered enhancements, such as

flashing beacons and speed feedback signs, are not recommended.

Crash Reduction Factors

Safety improvements can reduce the number and severity of crashes. The current state of the

practice in safety is to utilize crash prediction methods as much as possible to assist in

prioritizing safety improvement countermeasures. One commonly used predictive method to

determine the effectiveness of a safety improvement is to determine the Crash Reduction Factor

(CRF)4

.

The CRF is widely used within Federal Lands Highway Divisions as a means to measure the

expected performance of a safety improvement. Basically, higher CRF percentages indicate a

greater expected reduction in the number of crashes. As part of the description of the short-term,

long-term improvements, the CRF value is given for several of the improvements listed below.

See Table 1 for a cost breakdown of the proposed Engineering improvements. Table 1 can be

used as an aid in decision-making for programming various safety improvements by priority and

initial cost. In other words, improvements can be ranked by short-term, long-term, lower cost, and

higher cost. Forest management can use the information to rank low-priority and high-priority
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improvement projects.

Engineering

Short Term, Lower Cost improvements

• Signs

o Upgrading worn and damaged signs to meet the latest retroreflectivity

requirements will improve visibility in dark and low-light conditions. Upgrading

signs to meet current retroreflectivity recommendations has been shown to reduce

the number of crashes by 10% (CRF-10).

o Installing OM3 Object Markers at cattleguards and OM2 Object Markers at

culverts will provide visual clues to drivers of obstacles near the road. The object

markers are particularly helpful in warning drivers under low light/night driving

conditions.

o If it is not practical to use the Object Markers and a Type 1 Delineator is

preferred, use a white reflector lens, instead of an amber or red lens.

o Installing Type 1 Delineators along steep fill slopes and horizontal curves will

also provide visual clues to drivers. Delineators have been shown to reduce the

number of crashes by 30% (CRF-30). See Appendix D for MUTCD delineator

installation recommendations.

o Installing curve warning signs with advisory speed plaques at select curves is an

effective means to communicate with the traveling public and reduce speeds.

o Install pedestrian warning signs in areas where pedestrians frequently use the road

to access swimming holes. Use the fluorescent yellow-green sheeting. This will

increase driver awareness and expectancy.

o Replace sign posts that have the raised splice so that the splice is a maximum of

4” above the ground surface. See Appendix D.

• Culvert Improvements

o Install OM3 Object Markers on all four corners of the concrete box culvert

structures. Install the OM3 Object Markers so that the bottom of the sign is 4’

above the road surface, and the inner-most edge of the sign panel lines up with the

closest edge of the hazard.

o Clean existing CMP culverts and install riprap at outlet to reduce erosion.

• Roadside Treatments

o Consider providing a minimum 3’ unobstructed clear area where ever possible

as long as there is sufficient room to do so and there are no adverse

environmental effects. This will provide an additional recoverable area for

errant vehicles and will increase driver expectancy.

• Pullouts

o Consider grading pullouts on alternating sides of the road especially near the
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narrower sections of roadway, as long as there is adequate room to do so and there

are no adverse environmental impacts. More pullouts will provide refuge for

vehicles to pull over when encountering on-coming traffic.

• Vegetation

o Brushing trees and shrubs that are close to the edge of roadway will improve sight

distance, especially on the inside of curves and at the approaches to structures.

Long Term, Higher Cost improvements

• Concrete Box Culvert Structure Improvements

o Replace the bridge railing and install transition railing and guardrail end terminals

meeting Crash Test Level 2 (<45 MPH) criteria.

o Regrade the eroded corners at the concrete box culvert (MP 1.6).

• Road Surfacing (see Appendix G)

• Utility

o Partner with the Fiber Optic utility company to relocate the line so that damaged

culverts can be replaced and lowered to the appropriate ditch grade elevation.

Enforcement

Short Term, Lower Cost improvements

• Yavapai County has provided crash data. Continuing to collect this data is essential to

making conclusive decisions concerning the crashes and determining how to implement

effective safety countermeasures at hot-spot locations and throughout the alignment.

• Partner with Yavapai County to ensure that the crash data is documented and all crash

report fields, such as direction of travel, latitude and longitude coordinates, driver

behavior, object struck, etc. are consistently filled out.

Long Term, Higher Cost improvements

• Consider establishing a part-time position to maintain and analyze the crash data within

the Forest. The position could be a shared/rotational assignment with the adjoining Tonto

and Prescott National Forests.

Education

Short Term, Lower Cost improvements

• Continue to utilize the existing bulletin boards to post pamphlets and brochures. This is

an effective way to inform the users of safety concerns along the roadway, such as road

conditions, special events, road closures, etc.

• Educating the public can be accomplished by using readily understood traffic signs that

comply with the MUTCD. While signing is usually considered an engineering

countermeasure, it also provides for consistent communication with drivers.
33 | Page

Long Term, Higher Cost improvements

• One means to communicate with the traveling public is through social media. This is

becoming an increasingly effective and popular method to educate the public. Coconino

Forest has a Public Affairs Officer who maintains the website and issues press releases.

The Forest might consider adding real-time information on roadway conditions, safety

concerns, or to simply remind the public to avoid speeding, distracted driving, etc. to

the existing Forest website.

• Consider adding a special sign near MP 0.0 notifying visitors that there is no cell phone

coverage along the route. Coordinate with Law Enforcement to define what visitors

should do in the case of an emergency.

Emergency Response

Long Term, Higher Cost improvements

• Since the Tonto National Forest portion of NFSR 708 is closed, emergency response

must use SH 260 from Camp Verde, AZ. Helicopters cannot land in the area, so all

response is from road vehicles. There are sections of the road which are very narrow

and deeply rutted, and emergency vehicles may have difficulty passing an on-coming

vehicle. Resurfacing the road, installing pullouts, and providing a consistent width, as

much as practical, will reduce this conflict.
34 | Page

Table 1. NFSR 708 Recommended Improvements

Priority

No.

Type of

Improvement

Suggested

Implementation

Timeframe

Preliminary

Cost Estimate

1 Signing 1 Short Term $44,000

2 Install object markers/delineators 2 Short Term $26,100

3 Brushing trees, shrubs Short Term $8,000

4 Clean culverts and place riprap at outlet 3 Short Term $200,000

5 Grading pullouts 4 Short Term $40,000

6 Replace spliced sign posts 5 Short Term $3,600

SHORT TERM TOTALS $321,700

7 Bridge railing, transition railing,

and end terminals 6 Long Term $94,000

8 Relocate fiber optic line Long Term $3,000,000 7

9 Replace culverts, install riprap,

and flared end sections 8 Long Term $360,000

LONG TERM TOTALS $3,454,000 9

1 Assume 110 signs (Curve warning, Steep Grade, Chevrons) at $400/sign

2 Assume 30 OM3 Object Markers at $170 each; and 500 Type 1 Delineators at $42 each

3 Assume 50 culverts at $4,000/culvert

4 Assume 10 pullouts at $4,000 each. See Appendix D, Figure D13

5 Assume 30 posts at approximately $120/post (materials only)

6 Assume 180’ railing @ $250/lf; 12 end terminals @ $2500 each; and 150’ of transition railing @ $125/lf.

7 Estimate only

8 Assume 40 - 36” corrugated metal pipe culverts with riprap @ $9,000/culvert

9 Long Term total does not include Surfacing Options A, B, or C in Appendix G.
35 | Page

In conclusion, Coconino National Forest is commended for actively seeking ways to improve

safety on the roadway. NFSR 708 was chosen for a safety assessment due to several conditions:

• Road surface conditions (washboarding)

• Roadway characteristics (narrow width, steep fills, high cut slopes, sharp curves,

limited sight distance, erosion at drainage structures)

• Driver behavior (speeding)

• Vehicle and pedestrian conflict

The recommendations for each phase (short-term, long-term, lower cost, and higher cost) are

intended to assist the Forest in determining when to program roadway safety improvements. The

Forest is encouraged to modify the priority list as necessary to address concerns as they arise.
36 | Page

V. References

1 AASHTO, Roadside Design Guide, 4th Edition, 2011

2 AASHTO, Guidelines for Geometric Design of Very Low-Volume Local Rural Roads (ADT </=

400), 2001

3 Manual on Uniform Traffic Control Devices, 2009, Rev. 1, Rev. 2 

http://mutcd.fhwa.dot.gov/pdfs/2009r1r2/pdf_index.htm

4 FHWA, Crash Modification Clearinghouse

http://www.cmfclearinghouse.org/index.cfm
37 | Page

VI. Appendices
38 | Page

Appendix A

Driving Log/Proposed Mitigation

Mile

Post

Log Description Photo

(Appendix B)

Proposed Mitigation

0.0

Begin NFSR 708.

Gate and Cattleguard. Pullout on left.

Information kiosk. Special Primitive

Road and Narrow Rough Road warning

signs.

1 - 5

Install OM3 Object Markers at cattleguards

at the minimum height per MUTCD Section

2C.63

Replace special warning signs according to

MUTCD retroreflectivity requirements. See

Appendix C.

0.1 Road width is 21’.

0.3 Deep roadside ditches. 6 - 7

0.3 Culvert without object marker. 8 Install OM2 signs. See Appendix D.

0.4 Curve warning sign.

Culvert with headwall. No OM3 signs. Install OM2 signs. See Appendix D.

0.6

Stop ahead sign with poor

retroreflectivity in northbound

direction.

Install W3-1 Stop Ahead sign according to

MUTCD retroreflectivity requirements. See

Appendix C.

1.0 OM2 signs on cattleguard installed too

low.

11

Remove OM2 Object Markers.

Install OM3 Object Markers at cattleguards

at the minimum height per MUTCD Section

2C.63

1.2 Limited sight distance curve.

For consistency, install W1-1 signs for

curves under 30 mph design speed. See

MUTCD Section 2C.05

1.3 Narrow Bridge sign with poor

retroreflectivity

Install W5-2 sign according to MUTCD

retroreflectivity requirements. See Appendix

C.

1.5 Limited sight distance curve.

Chevron signs mounted too low. 14

Install Chevrons in both directions at the

minimum height per MUTCD Section

2C.63.

1.6 Erosion at culvert Install OM2 signs. See Appendix D.

1.7 New installation of cattleguard sign

2.0

Road narrows to 19’ at concrete box

culvert. Washboarding is 2”-4” deep.

W1-1 Curve to left sign.

Install OM3 signs at the minimum height

per MUTCD Section 2C.63. See Appendix

D.

Replace W1-1 sign according to MUTCD

retroreflectivity requirements. See

Appendix C.
39 | Page

Mile

Post

Log Description Photo

(Appendix B)

Proposed Mitigation

2.1

Concrete Box Culvert on horizontal

curve. Severe erosion. Curve to right

sign in northbound direction needs to be

remounted.

Install OM3 signs at the minimum height

per MUTCD Section 2C.63.

Upgrade bridge railing and install guardrail

with end terminals meeting Test Level 2

(<45 MPH) criteria.

2.2

Hairpin curve sign with poor

retroreflectivity. Steep fill slopes.

Limited sight distance curve.

15 - 16

Install W1-11 sign according to MUTCD

retroreflectivity requirements. See Appendix

C.

Install Chevron signs according to MUTCD

Figure 2C-2. Install Type 1 delineators

along fill slope. See Appendix D.

2.4 Typical U-channel post. Sharp Curve to

right sign is new.

Replace sign posts using FHWA approved

splice location and hardware. See

Appendix D.

2.6 Culvert with OM3s. Winding Curves

sign

Install W1-5 sign according to MUTCD

retroreflectivity requirements. See Appendix

C.

Install OM3 Object Markers at the

minimum height per MUTCD Section

2C.63

2.9 New Hairpin Curve sign installation

3.0 Pullout

3.2 Winding Road to left sign. Install Chevrons or Type 1 delineators. See

Appendix D.

3.9 Road narrows to 17’ wide. Steep fill

slope. Regrade road. See Appendix G

4.0 to

4.1

Road widens to 21’. Recently place

millings with aggregate to stabilize

surface and decrease washboarding.

Regrade road. See Appendix G

4.5 Recent tree trimming at sign. 17

To be consistent, replace the W1-2 sign with

a W 1-1 since the design speed on the curve

is less than 30 MPH.

4.8

Road widens. 30 MPH sign. Horizontal

curve with cattleguard. Missing OM3

sign in northbound direction.

Install OM3 signs at all four corners of

cattleguard at correct height.

4.9 Road narrows to 15’ wide. Regrade road. See Appendix G

5.1

Chevrons signs are damaged. Good

sight distance for the Hairpin Curve

sign.

Replace Chevron signs. See MUTCD Figure

2C-2. See Appendix D.
40 | Page

Mile

Post

Log Description Photo

(Appendix B)

Proposed Mitigation

5.2 to

5.8

Concrete Box Culvert with metal

railing.

Narrow Bridge signs in both directions.

Road width is 18’.

19

Trim vegetation on inside of curves.

Install OM3 Object Markers at the

minimum height per MUTCD Section

2C.63.

Upgrade bridge railing and install guardrail

with end terminals meeting Test Level 2

(<45 MPH) criteria.

5.5 Reverse Curve sign blocked by

vegetation Trimvegetation.

5.6 Hairpin curve with Chevrons

Replace signs to meet current

retroreflectivity requirements.

See Appendix C.

Install Chevron signs per MUTCD Figure

2C-2. See Appendix D.

6.1

Hairpin curve with steep fill slopes.

Two Chevron signs in northbound

direction only

Install Chevron signs per MUTCD Figure

2C-2. See Appendix D.

6.2 to

6.3

Limited sight distance. Hairpin Curve

sign. Trimvegetation.

6.7 Hairpin Curve sign.

Replace sign to meet current

retroreflectivityrequirements.

See Appendix C.

7.5 Limited sight distance Trimvegetation.

7.7 Low Water Crossing 22 Install W8-2 DIP sign.

7.9

Road narrows to 12’ at cattleguard.

Low Water Crossing near campsite.

DIP sign in northbound direction only.

Install cattleguard warning sign.

Install additional DIP sign in southbound

direction.

8.9 Curve to Left sign installed too low. Replace sign at the minimum height per

MUTCD Section 2C.63.

9.8 Horizontal curve with limited sight

distance. Pullout. Trimvegetation.

9.9 Hairpin Curve to Right sign installed

too low.

Replace sign at the minimum height per

MUTCD Section 2C.63.

10.1 Damaged Reverse Curve to right Replace sign at the minimum height per

MUTCD Section 2C.63.

10.3 Advance warning for cattleguard before

horizontal curve

Continue placing advance cattleguard signs

in areas of limited sight distance.
41 | Page

Mile

Post

Log Description Photo

(Appendix B)

Proposed Mitigation

10.4 Road narrows to 12’ at cattleguard.

Install OM3 Object Markers at the

minimum height per MUTCD Section

2C.63.

10.5 Visitor parking area. Entering a steep

downgrade section of road.

Install advance warning for steep grade with

advisory distance plaque in both directions.

Install Hairpin Curve to left sign in

northbound direction.

10.7 to

10.9

Steep downgrade. Vegetation close to

edge of road. Road narrows. Vandalized

signs.

Install delineators on the fill slope side.

Brushing of trees.

11.3 to

11.4

Winding Curves warning sign with poor

retroreflectivity. Vegetation close to

edge of road.

Trimvegetation.

Replace sign to meet current

retroreflectivityrequirements.

See Appendix C.

11.7 Culvert with no cover 26 Regrade road. See Appendix G

12.6 to

12.9

Winding Curves warning sign. Steep

fill slopes and rock outcrop. Limited

sight distance on horizontal curve

Replace sign to meet current

retroreflectivityrequirements.

See Appendix C.

12.9 Hidden sign with poor retroreflectivity 28

Trimvegetation.

Replace sign to meet current

retroreflectivityrequirements.

See Appendix C.

13.4 Narrow Road and Curve sign

Replace sign to meet current

retroreflectivityrequirements.

See Appendix C.

13.8 Limited sight distance on horizontal

curve.

Install Chevrons. See MUTCD Figure 2C-2.

See Appendix D.

14.0 Concrete box culvert with metal railing.

Install OM3 Object Markers at the

minimum height per MUTCD Section

2C.63.

Upgrade bridge railing and install guardrail

with end terminals meeting Test Level 2

(<45 MPH) criteria.

14.8

NFSR 502 (Childs Road). Intersection

gate. Intersection advance warning sign

with poor retroreflectivity. Forest

recently added a STOP sign on Rt 708.

28 - 29

Install W2-3 intersection sign to meet

current retroreflectivity requirements. See

Appendix C.

15.1 Cattleguard. Pedestrians using road to

accessswimming holes. 30

Install W11-2 Advance Pedestrian Warning

sign with W16-2P NEXT XX FEET

Advisory Plaque

15.3 Cattleguard sign angled away from

traffic.

Orient sign to face traffic per MUTCD

requirements.
42 | Page

Mile

Post

Log Description Photo

(Appendix B)

Proposed Mitigation

15.5 Pedestrians using road to access

swimming holes 31

Install W11-2 Advance Pedestrian Warning

sign with W16-2P NEXT XX FEET

Advisory Plaque

15.8 End NFSR708.

North end of Fossil Creek Bridge.
43 | Page

Appendix B

Site Photos

Photos 1-3. MP 0.0

Begin NFSR708 at Cattleguard.

Installation of OM3 Object Marker

signs at varying heights.

Good delineation of pulloutlimits.

Good installation of information kiosk.

SuggestedImprovements:

Short Term. Use kiosk for posting the

CoconinoNational Forest website

information.

Install Type 1 delineators to help

define the kiosk location especially in

low-light conditions.

Install OM3 signs at consistent height

based on MUTCD requirements.

Ensure that boulders are not placed

within the clear zone of the roadway.
44 | Page

Photos 4 and 5. MP 0.0

Specially fabricated road conditions 

warning signs. Signs are damaged with 

very low retroreflectivity.

SuggestedImprovements:

Short Term. Replace signs meeting current 

MUTCD retroreflectivity requirements. 

See Appendix C.

Consider mounting a W7-3aP distance 

plaque for the next 16 miles with the 

Narrow Rough Road sign.
45 | Page

Photos 6 and 7. MP 0.3

Typical deep roadside ditches.

Road surfacewashboarding.

SuggestedImprovements:

Short Term. Install back-to-back Type

1 delineators along the outside edge

or roadway to increase visibility and

driver awareness on limited sight

distance horizontal curves.

Long Term. Resurface the road to

decreasewashboarding.

See Appendix G.
46 | Page

Photos 8 and 9. MP 0.4

Culvertinlet/outlet damage. Damaged

OM2 Object Marker. Fiber Optic is

buried along roadside preventing

fixing the damaged culvert.

SuggestedImprovements:

Short Term. Install OM2 Object

Markers on both sides of the road.

Long Term. Relocate fiber optic line.

Replace culverts to the natural

channel elevation and install cutoff

wall as needed to reduce erosion,

install riprap, and regrade the ditch.
47 | Page

Photo 11. MP 1.0

OM2 Object Markers are damaged and

installed too low.

SuggestedImprovements:

Short Term. Remove OM2 Object

Markers at all four corners.

Install OM3 Object Markers at MUTCD

height requirements.

Photo 10. MP 0.8

Typical tangent section of road. Steep fill

slope at culvert inlet.

SuggestedImprovements:

Short Term. Install Type 1 Delineators

along edge of road.

Long Term. Reconstruct road with 1:3 or

flatter foreslope.

Replace the culvert to the natural

channel elevation and install cutoff wall

as needed to reduce erosion, install

riprap, and regrade the ditch.
48 | Page

Photos 12 and 13. MP 1.5

OM3 Object Markers are installed

too low.

Bridge railing is not crashworthy.

SuggestedImprovements:

Short Term. ReplaceOM3 Object

Markers at all four corners; install at

MUTCDheight requirements.

Long Term. Replace bridge rail

meeting Test Level 2 (TL-2) criteria.

Install transition rail and end

terminals meeting TL-2 criteria.

See Appendix E.
49 | Page

Photo 16. MP 2.2

Steep fill slope and limited sight

distance horizontal and vertical curve.

SuggestedImprovements:

Short Term. Install Type 1 Delineators

along edge of road.

Photo 15. MP 2.2

Hairpin Turn. Good installation in

advance of curve.

SuggestedImprovements:

Short Term. Install back-to-back

Chevron signs per MUTCD

requirements. See Appendix D.

Photo 14. MP 1.5

Chevron signs installed in one

direction only. Chevrons not at

correct height

SuggestedImprovements:

Short Term. Install back-to-back

Chevron signs per MUTCD

requirements. See Appendix D.
50 | Page

Photo 17. MP 4.5

Good example of recent tree trimming

to improve visibility of the sign.

SuggestedImprovements:

Short Term. For consistency, replace

all W1-2 signs with W1-1 signs since

the curve design speed is less than 30

MPH. See MUTCD Section 2C.07

Photo 18. MP 5.1

Chevron signs installed too low.

Vegetation is partially blocking view.

SuggestedImprovements:

Short Term. Install back-to-back

Chevron signs per MUTCD

requirements. See Appendix D.

Trim vegetation.

Photo 19. MP 5.2

Structure. Road narrows to 18’.

SuggestedImprovements:

Short Term. Install OM3 at minimum

height per MUTCD requirements. See

Appendix D.

Long Term. Replace bridge rail

meeting Test Level 2 (TL-2) criteria.

Install transition rail and end

terminals meeting TL-2 criteria.

See Appendix E.
51 | Page

Photo 21.

Limited sight distance horizontal

curve.

SuggestedImprovements:

Short Term. Trim vegetation. Install

back-to-back Type 1 Delineators on

outside of curve.

Photo 20.

Severe washboarding with exposed

bedrock.

SuggestedImprovements:

Long Term. Resurface road. See

Appendix G.
52 | Page

Photo 22.

Road narrows. Advance warning

signing for Low Water Crossing and

Cattleguard. Area often has

overgrownvegetation.

SuggestedImprovements:

Short Term. Trim vegetation. Upgrade

signs to meet current MUTCD retroreflectivityrequirements.

Install W5-1 Road Narrows sign in

each direction.
53 | Page

Photos 23. and 24.

Damaged signs

SuggestedImprovements:

Short Term. Upgrade signs to meet

current MUTCDretroreflectivity

requirements. See Appendix C.

Photo 25.

Existing pullout.

SuggestedImprovements:

Short Term. Install additional

pullouts especially near narrow

sections of the road as long as there

are no adverse impacts. See Appendix

D, Figure D13.
54 | Page

Photo 28. MP 14.8

Good example of signing on gate

structure.

Photo 27.

Sign hidden by vegetation.

SuggestedImprovements:

Short Term. Trim vegetation to

improve visibility of the sign.

Photo 26.

Exposed culvert.

SuggestedImprovements:

Long Term. Resurface the road. See

Appendix G.
55 | Page

Photos 30 and 31.

Pedestrians on the road.

SuggestedImprovements:

Short Term. Install W11-2 pedestrian

warning signs with fluorescent yellowgreen background color for both

directions of travel. Add the W16-2P

sign for added notification to drivers.

Install the sign so that the W11-2 sign

panel is a minimum of 7’ above the near

edge of roadway.

Photo 29. MP 14.8

NFSR 708-NFSR 502 (Childs Road)

intersection. Recent STOP sign

installation.
56 | Page

Photo 32.

Typical example of spliced U-channel

sign post along NFSR 708. Note the

height of the splice and the

orientation of the bolt.

SuggestedImprovements:

Short Term. Replace sign posts using

FHWA approved splice location and

hardware. See Appendix D.
57 | Page

Appendix C

Maintaining Traffic Sign Retroreflectivity

Source:www.fhwa.dot.gov/retro

The Maintaining Traffic Sign Retroreflectivity document was first prepared in 2007, and later

revised in 2013 to incorporate MUTCD compliance dates. The June 14, 2014 date has come and

gone, and at this time, all agencies should have their sign assessment or management method in

place.

The FHWA Roadway Departure – Retroreflectivity website indicates, “The compliance date of

June 14, 2014 applies only to the implementation and continued use of an assessment or

management method that is designed to maintain regulatory and warning sign retroreflectivity at

or above the minimum retroreflectivity levels in [MUTCD] Table 2A-3. Agencies are expected to

add signs other than regulatory or warning to their method as resources allow.”

The FHWA Roadway Departure – Retroreflectivity website further states,

“Similar to other occurrences of signs that are no longer serviceable, agencies are expected to

prioritize replacement of these signs based on engineering considerations such as the relative

importance of the sign to the safety of the road user, volumes and speed of nighttime traffic, and

optimal use of limited resources, among others. Signs that are no longer serviceable might

demand a higher priority for replacement over other non-compliant signs that are replaced by

systematic upgrading or routine maintenance schedules. Accordingly, it is expected that the use

of the assessment or management method would serve to identify and program the replacement

of signs that are found to be or expected to be below the minimum retroreflectivity levels.”
58 | Page
59 | Page
60 | Page
61 | Page
62 | Page

Appendix D

RoadsideTreatments

Figure D1. Example of placing reflective tape on fixed objects, such

as trees or poles, that can’t be easily removed due to right-of-way

issues, environmental issues, or utility conflicts.

Figure D2. Example of placement of Chevron (W1-8) signs on

horizontal curve. Using the fluorescent yellow sheeting is preferred

since the fluorescent color adds to the overall visibility, especially

in low light/night driving conditions.
63 | Page

Typical Warning Signs

Source: MUTCD

Figure D3. Chevron for use on sharp horizontal curves

12” x 18” (min.)

Figure D4. Type 2 Object Markers for use with obstructions adjacent to the roadway

(headwalls, stone masonry walls, culvert end sections).

Figure D5. Type 3 Object Markers for use with obstructions adjacent to, or within, the roadway

(headwalls, culvert end sections, and cattleguards).
64 | Page

Figure D6. Advisory Speed Plaque.

Type 1 Rigid Post Type 2 Flexible Post (Carsonite)

Figure D7. Delineators for use along the edge of roadway

(steep slopes, added night visibility).

Source: CFLHD

On tangent sections of roadway, install delineators with white reflective lens or tape

at a minimum spacing of 200 feet.

Note: the Carsonite post is not appropriate for the bedrock conditions along

NFSR 708

Minimum dimension of

3” (diameter or square)
65 | Page

Figure D8. Delineator Spacing on Curves (Source: MUTCD, Section 3F.04)
66 | Page

Figure D9. Example of Delineator Spacing on Curves (Source: MUTCD, Section 3F.03)
67 | Page

Figures D10 and D11 Schematic drawings of splice location 4” (max) above ground.

3’ anchor post (base) is embedded at least 32”

Note the bolt and nut orientation.
68 | Page

Figure D12 One example of a crash tested sign support system

Crash Test Level 2 (TL-2) for <45 MPH.

Note the bolts, washers, and retainer strap.

Source: http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/breakaway/pdf/ss09.pdf

To view other U Channel Post products and their crash testing results:

http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/listing.cfm
69 | Page

Figure D13. Examples of pullout dimensions.

Source: CFLHD
70 | Page

Appendix E

W-Beam Guardrail Standards

Source: http://flh.fhwa.dot.gov/resources/standard/
71 | Page
72 | Page
73 | Page
74 | Page
75 | Page

Appendix F

Aesthetic

Guardrail

Source: http://safety.fhwa.dot.gov/roadway_dept/policy_guide/road_hardware/resource_charts/aesthetic.pdf

NCHRP 350 TL-2 Steel-Backed

Timber Rail

6” x 8” x 7’ timber post.

6” x 8” x 10”Wood blockouts/

Dynamic deflection = 4’-4”

No crashworthy end terminal. Must

anchor into backslope or flare

away.

NCHRP 350 TL-2 Log Rail

12” diameter x 7’ log post.

Wood blockouts notched into log

post.

Dynamic deflection = 4’-4”

No crashworthy end terminal. Must

anchor into backslope or flare

away.
76 | Page

NCHRP 350 TL-2 Log Rail

6” diameter wood-clad steel post.

Steel spacer unit separates the post

from the rail.

7” diameter log rail

Dynamic deflection = 4’-7”

No crashworthy end terminal. Must

anchor into backslope or flare

away.

NCHRP 350 TL-3 Rustic Metal

Beam Guardrail

Standard wood or steel posts.

Standard metal rail.

End terminals are treated with

same rustic appearance. Steel posts

can be treated with rustic

appearance.
77 | Page

Appendix G

Preliminary Existing Road Surface Investigation and

Recommendations- Technical Memorandum
Subject: USFS Route 708, Fossil Creek Road

Preliminary Existing Road Surface

Investigation and Recommendations

From: Rick Marquez, RocksolConsulting Group

Approved for distribution by:

Mike Voth, 

Senior Pavements and Materials Engineer

CFLHD, Lakewood, CO

To: Barbara Burke,

HighwaySafety Engineer

CFLHD, Lakewood, CO

INTRODUCTION

Memorandum

Date: September 8, 2016

This memorandum presents an assessment of the existing traveled way surface conditions of

Forest Service (FS) Route 708 (Fossil Creek Road) located in the Coconino National Forest.

The route is approximately 16.0 miles in length beginning at the junction of SH260 and

proceeding south-southeast to the terminus (see Photo 1). The route provides recreational

(hiking/camping) and Forest access, with popular “natural spring swimming pools” at Fossil 

Creek

This memo also presents options and associated costs that may be considered to improve the 

ride-ability of the existing surface conditions as well as improve drainage. 
2

Photo 1, MP 0.00 Junction of AZ SH260 and Fossil CreekRoad

SCOPE

A roadway visual condition survey was conducted on July 12, 2016 of Route 708 to provide 

recommendations for rehabilitation and route maintenance process improvements. The route

conditions survey was conducted from MP 0.00(Jct. SH 260) to the terminus of the route at

approximate MP 16.0. The survey was conducted by Rick Marquez (Rocksol Consulting

Group/Central Federal Lands) in company with Raymond Holt, US Forest Service Facility

Engineer, Coconino National Forest. The intent of the survey was to address the roadway 

surfacing conditions and provide recommendations for issues and concerns that the

Forest Service has with the existing condition of the route. 

ISSUES

The following is a summary of FS issues, concerns, and considerations pertaining to the route 

conditions: 

1. Rough, gravel road with boulders and bedrock protruding above the roadway riding surface. 

2. A very small amount of previously placed aggregate remains in place.

3. Coconino Forest wants options for re-graveling to improve drivability but with limited grade

raise due to the existing narrow road. Options and discussion in the memo include;

• Traditional surface gravel with Plasticity Index (PI) using clay. 

• Stabilized surface gravel with a dust palliative and limited grade adjustment. 

• Target for expected performance life. 

• Estimated costs for the options.

4. Is it practical to excavate and lower the grade to gain additional width?

5. Can cut slopes be used to both allow for widening and be used as a source for material?

6. Roadway surface is to remain gravel, because it is very low volume road (typically < 400 

vehicles per day). 
3

FINDINGS/DISCUSSIONSOFISSUES/CONCERNS AS NOTED ABOVE

Roadway typical section: The roadway ranges in width from 17 to 21 feet, with numerous

sharp curves and some areas where vertical grades range from 12-14 percent.

The surfacing material of the roadway from beginning to the end is a combination of

Soil/aggregate with the majority of the surface consisting of large rocks (6”-24”) protruding

through the surface of the roadway, see Photos 2, 3, and 4. The large number of rocks

protruding through the surface makes “normal” maintenance blading of the surface difficult on 

the majority of the route and impossible to maintain a smooth surface for the traveling

public. Protruding rocks also make it difficult to maintain adequate roadway cross-section

(superelevation and crown) and positive drainage. 

In addition, due to the numerous rocks protruding through the surface of the roadway which

create a rough, irregular surface, it is impossible to maintain a consistent depth of 

aggregate base on the surface of the existing roadway. 

Photo 2 Typicalsurface with protruding rock
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Photos 3 and 4, Typical surface with protruding rocks

SURFACING OPTIONS

The following surfacing options are summarized: 

A. In place crushing of existing material

B. Use of recycled asphalt pavement(RAP) and aggregate base on the existing surface

C. Apply aggregate base w/PI only 

D. Lowering the roadway grade 
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A. In-place crushing: Due the large number of protruding rocks on the surface it would require 

a major reconstruction project to remove the large volume of rocks on the roadway surface

and reconstruct a smooth finished subgrade with aggregate base surface.

Recommendations: Look at mobile/portable onsite crushing equipment and process to a 

minimum depth of 6-inches. Crush the existing surface material to a maximum size of 1.5 

inches and utilize the resulting crushed material as aggregate surfacing. If this option is

chosen, a dust palliative is recommended for controlling dust and as a binder to prevent 

raveling and loss of surfacing aggregate. This option would also require the route closure due 

to size of equipment performing the work.

B. RAP with aggregate base: The use of Recycled Asphalt Mix (RAP) 50/50 with aggregate

base on this route may be a viable application. The RAP mixed with aggregate base would

provide a mixture that would bind together, and provide a smoother riding surface with 

consistent depth of cover over the existing protruding rock. Recommendations: Place a 

minimum, 3-inch layer of Recycled Asphalt Mix (RAP) mixed 50/50 with aggregate base

on the existing surface to cover the numerous protruding rocks on the surface. RAP, having

asphalt binder would tend to bind together and stay in place between surface rock in lieu of

only aggregate base, which tends to ravel and eventually be removed by traffic or wash 

away from the surface of roadway. Recommend constructing a trial section of 1 to 2 miles 

in length on a typical curvilinear section similar to the remainder of the route; for example,

between MP 1 and MP 3. Adjust the ratio of RAP to aggregate base to ensure a mixture

that will provide acceptable results. Once an acceptable ratio is achieved, compact the

mixture with a pneumatic roller. If this option is chosen, a dust palliative is recommended

for controlling dust and as a binder to prevent raveling and loss of surfacing aggregate. 

C. Aggregate base w/PI only: Thisis not a recommended option because the large volume of

protruding rock on the surface of the road would prohibit any type of aggregate base to

remain on the surface due to traffic, weather, steep grades and sharp curves. However, if 

this option is chosen, dust palliative application is recommended to assist in binding the aggregate 

and maintaining dust control. This option would require periodic applications at approximate

6-month intervals depending upon traffic volume and precipitation.

D. Lowering of the grade: This is not a recommended option for the following reasons:

1) Lowering the grade without excavating into the roadway cuts sections would eliminate

the ditch line and potentially adversely affect drainage with very little gain in width. 

2) Lowering the grade and shifting the road template into the cut slopes would result in 

extensive excavation of the cut slopes (some of which are solid bedrock and could 

require blasting) and into the subgrade, which would result in producing similar rock 

material that is unsuitable for subgrade finishing. As a result the surface would continue 

to exhibit the same protruding large rock resulting in rough road conditions. 

3) Lowering the grade is most likely cost prohibitive.
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 ADDITIONALCONCERNS

1) Roadway ditches: Roadway ditches left and right are in need of maintenance which

includes removing large boulders, debris and vegetation. 

2) Roadway culverts: There are approximately 130 culverts on this route. Most of the 

culverts are 18-24 inch diameter. Most of the culverts on the route do not have

adequate cover and most have been damaged as a result of maintenance and traffic. 

Culverts are beyond their design life and are in need of replacement, see Photo 5. 

3) Roadway structures: There are 5 bridges/drainage structures on this route. The

measured width, from inside curb to inside curb, is 20-21 feet. The structures on this 

route are in need of inspection for structural integrity. Some of these structures appear

to have very old stone facing that may be historic, see Photos 6 & 7. Further 

investigation is recommended. 

Photo 5, Typical exposed/damaged culverts
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Photo 6, Existing bridge/drainage structure

Photo 7, Existing structure with potential historic headwalls
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ESTIMATED COST FOR OPTIONS A, B & C

OPTION DESCRIPTION QUANTITY UNIT 

price/mile COST

A 

In-place 

Crushing

Dust Palliative

16 miles

5280 x 20/9 x 0.4 x 1.3/2000 = 3.1 tons/mi

(L) (W) (RATE) (WT/GAL)

 

Total Option A

$35,000/mi

$500/mi

$560,000

$8,000

$568,000

B 

RAP and 

Aggregate Base

(50/50)

 Dust Palliative

RAP = 5280 x 20 x 0.17 x 138/2000 = 1239 tons/mile

 (L) (W) (D) (PCF)

Agg. Base = 5280 x 20 x 0.17 x 138/2000 = 1239

tons/mile

 (L) (W) (D) (PCF) 

5280 x 20/9 x 0.4 x 1.3/2000 = 3.1 tons/mi 

(L) (W) (RATE) (WT/GAL)

Total Option B

$43,365/mi

$37,170/mi

$500/mi

$693,840

 $594,720

$8,000

$1,296,600

C 

Aggregate Base 

w/PI only

Dust Palliative

Agg. Base = 5280 x 20 x 0.33 x 138/2000 = 2405 

tons/mile

 (L) (W) (D) (PCF) 

5280 x 20/9 x 0.4 x 138/2000 = 3.1 tons/mi

(L) (W) (RATE) (WT/GAL)

Total Option C

 

$72,150/mi

$500/mi

$1,154,400

$8,000.00

$1,162400

 NOTES:

1. Cost is based on 16 miles of road surfacing and rounded to nearest $100.

2. Unit prices used for estimating: RAP=$35/ton, CAB=$30/ton, Palliative=$160/ton

3. Option “A” includes equipment rental and operating cost for in place crushing, does not include finishing, compacting or mobilization

4. Dust Palliative cost does not include finishing, compacting and watering.