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Environmental assessment and nationwide section 4(f) evaluation Canyon Ferry Road : STPS 430-1(5)1; CN 4480, Lewis and Clark County, Montana (Volume 2003) online

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rural section near RP 7.3, RP 8.1, andRP 8.6 are not adequate for tiie applicable design criteria.

Vertical Alignment. The existing vertical alignment is adequate from the project's begimiing
to about RP 5.0 where the road encounters rolling tenain. Sight distance is substandard at most
veitical curves east of RP 5.0 since the existing road closely follows tiie lully tenain.

The project encounters a long grade between RP 4.6 and 6.0. The steepest grade in this segment
is about 10 percent, which exceeds tiie maximum design gradient of 7 peicent. The project
includes anotiier grade fioniRP 6.8 to 7.1, which is approximately 6 percent. Canyon Ferry
Road intersects Spokane Creek Road on a short, relatively steep giade.


Canyon Ferry Road: STPS 430-1(5} 1 Environmental Assessment

Intersection Geometries. Most of the intersections along the commercial/residential portion
of the project are simple m design and located on flat ten'ain. Most existing intersections have
"T" or four -leg con&guiations. Geometiic problems aie apparent at the intersection of Canyon
Ferry Road and Wylie Drive, particularly for large tracks with trailers. Eastbound tiafQc on
Canyon Feny Road stopped at Wylie Drive may occasionally have to stop well short of tlie stop
line or have to back up to allow large trucks with trailers to turn west onto Canyon Feny Road
fiom Wylie Drive. Reconstructionoftheintersectionwithlarger radii in each quadrant of tlie
intersection is necessaiy to alleviate this undesuable geometiic and operating condition at
Canyon Ferry Road and Wylie Drive.

The intersection of Canyon Ferry Road and Spokane Creek Road in the rural segment is located
on a curve, has steep grades on all approaches and sight distance restrictions due to its skewed
configuration. The intersection is cmrently configiu'ed witli Spokane Creek Road as the major
tlirough road requiring the predominant eastbound fiaffic on Canyon Ferry Road to stop.
Eastbound motorists have minimal room to stop at tlie intersection.

Studies indicate that 70 percent of all traffic passmg through the Canyon Feny Road/Spokane
Creek Road intersection tiun fiom or onto Canyon Ferry Road. This tiaffic pattern indicates a
need to reconfigure the intersection so that tiie major traffic movement would be given
preference and would not be requued to turn or stop.


MDT periodically conducts detailed evaluations of tire condition of bndges on tire state highway
system and on many off-system roads. The evaluations are used to develop a Sufficiency Rating
to measure the condition of each bridge. The Sufficiency Rating is a composite of several ratings
of individual bridge items that consider the stnictuial condition and geometry of tire bridge. A
bridge with a low ratmg on stractural items vvdll be designated as "stractmally deficient" and a
bridge with a poor rating for geometry items will be designated as "functionally obsolete."
Sufficiency Ratings are based on a 100-point scale.

The Canyon Feny Road project contains three bndges that are proposed for replacement with
eitiier new stnictmes or large diameter culverts due to their deteriorated physical condition, lack
of adequate deck width or incompatibility vvdth tire proposed road design's horizontal or vertical
features. The locations, bridge types, date of construction, and Sufficiency Ratings for these
bridges are listed m TABLE 3.

The Helena Valley Canal Bridge at RP 4.77 is considered to be functionally obsolete and eligible
for rehabilitation by MDT's Bridge Bureau based on tiie results of the stnictiue's inspections in
August 2002. The bridge at RP 4.77 would also not meet proposed road elevations or
accommodate tiieproposedroadway width of 12.0m (40 feet) for tire rural section of the project

The load Irmit for bridges in tiie project area should be 36-tons. MDT's Bridge Bureau rated the
load-carrying capacity of tiie bridge at RP 8.68 ("No Name" Spring Creek) at 15-tons. The
bridge at "No Name"" Spring Creek has undergone at least one temporary fix by MDT
maintenance crews to protect its structural load canying capacity. Prior to tiiis project's


Canyon Ferry Road; STPS 430-1(5} 1

Environmental Assessment

nomination, MDT had proposed to replace the bridge with a large culvert. Because of tire low
load rating, any larger-tlian-noimal tiiickloads could be at risk crossing this bridge. Additionally,
tlie budge at "No Name"" Spring Creek cannot accommodate tire proposed 12.0 m (40 feet) wide


TABLE 3: Bridge Locations, Types, and Sufficiency Ratings
1 Canyon Ferry Road

Location (RP)
MDT Bridge No.

Bridge Length and
Roadway Width

Structure Type



Helena Valley Canal


13.41 mx 7.35 m
(44feetx 24.1 feet)

Two- span timber



"No Name" Spring Creek

(RP 8.68)

5.57 111 X 7.70 m

Single-span timber



Helena Valley Canal

{RP 4.70**)

21 .94 mx 9.39 m
(72 feet X 30.8 feet)

Three-span timber



* Rating based on results of inspection during April and August 2002.

** Bridge location referenced to Spokane Creek Road (Secondaiy Route 284).

Anotliei bridge crossing tlie Helena Valley Canal (at RP 4.70 on Spokane Creek Road) would
need to be replaced due to its inadequate width and the mabihty to incorporate the structiue and
its approaches mto the proposed recon&giuation of the Canyon Ferry Road/Spokane Creek Road
uitersection and transition to the existmg liighway at tlie eastern project tenninus.

The location of bridges and major imgation structures along Canyon Feiiy Road are shown in
FIGURE 7 in Part IV of the EA.


The surfacing of Canyon Ferry Road varies considerably over the length of the project due to
manner in wliich the road was originally built and later improved. Testmg shows that the road's
surface consists of bitummous surfacing material ranging in tliickness fi'oin 1 5 millimeters (mm),
or about 0.5 mches, to 110 mm (4.3 inches) over gravel base material rangmg &om50 mm (2
inches) to 255 mm (1 mches) in thickness.

Overall, the existing road surface is in poor condition and exliibits many forms of pavement
distress (such as raveling, bleeding, pot holes, iiitting, and various types of surface cracking) that
affect tlie quality of the ridmg surface. Most of tlie existing liighway within tlie project coiTidor
has not received any major work, except for localized maintenance activities, since 1972.
However, MDT completed a large overlay project on the liighway fi'om tlie beginning of the
proposed Canyon Ferry Road project to Lake Helena Drive m 2000.

-21 -

Canyon Ferry Road: STPS 430-1(5} 1

Environmental Assessment

MDT annually collects data on pavement condition and rates the roughness of pavements on the
state road system. MDT uses tlie Average Ride Index (ARl), a measurement of pavement
rouglmess, as an indicator of pavement performance factors like driving comfort, vehicle
operating cost, and safety. The ARI is a to 100 scale that represents the nde quahty of the
pavement. The ARI scale values ranging fiom 80 to 100 indicate "Good" ride quality and values
fiom 60 to 79.9 indicate "Fan" ride quality. ARI values of less tlian 59.9 suggest the ride quality
of tlie pavement is "Poor."

MDT's most recent (July 25, 2002) ARI for Canyon Ferry Road between RP 1 .0 and 9.2 was 68,
suggesting the road's pavement has a fair ride quality. This liigher tlian expected rating is due to
tlie fact that a major portion of tlie roadway was overlaid m 2000.

C. Safety


Information about past motor vehicle accidents on Canyon Feny Road was reviewed to identify
long-term accident patterns and characteristics. Data fiom the Safety Management System, the
State's computerized accident recording system, provides information on the type, fiequency,
location and severity of each reported crash withm the project area . For this evaluation, the
accident history fiom October 1, 1991 to September 30, 2001 was reviewed for the Canyon Ferry
Road corridor between RP 1.00 and 9.241 and in the vicinity of Canyon Feny Road's
intersection with Spokane Creek Road.

The accident data revealed tliat a total of 200 accidents, mcluding one fatal crash and 85 crashes
tliat produced injuries, were investigated withm the Canyon Feny Road project conidor during
tlie specified period. A total of 1 48 accidents were mvestigated in the commercial/residential
section (between RP 1 .00 to 4.200) and 52 accidents were reported in tlie nual section (between
RP 4.201 to 9.241). Five additional accidents occuned along Spokane Creek Road witliin about
0.8 km (0.5 miles) distance of the Canyon Feny Road intersection. Please note that otlier fatal,
injury and property damage accidents have occurred within the project comdor since tlie end of
the ten-year accident study period ending in September 2001 .

TABLE 4 smnmarizes the major accident types and severity characteristics for the crashes that
were investigated on the route during the ten-year accident study period. FIGURE 3 shows the
generalized locations of reported motor vehicle accidents durmg tlie study period on Canyon
Ferry Road and on Spokane CreekRoadmthe vicinity of the intersection of these routes.

As the TABLE 4 shows, the ten-year accident rate for tlie commercial/residential and the rural
sections of the Canyon Ferry Road Study Area were 5.64 accidents per million vehicle miles of
travel (ACC/MVMT) and 1.46 ACC.MVMT, respectively. These rates compare to a statewide
average accident rate of 1 .77 ACC/MVMT for all rural Secondary Roads. The accident rate in
the commercral/residential section of the project conidor is nearly 3.2 times lirgher than tlie
statewide average for all rural Secondary Roads. The accrdent rate witliin tlie niral sectron of the


Canyon Ferry Road; STPS 430-1(5) 1

Environmental Assessment

o Property Damage Only
вАҐ Injury Accident

(includes incapacitating, non-incapacitating

and possible injury accidents)

Fatal Accident

Figure 3:

Accident History Map

October 1, 1991 thru September 30, 2001
RP 1.205 to RP 9.605


Canyon Ferry Road: STPS 430-1(5} 1

Environmental Assessment

corridor is slightly below tlie statewide average accident rate for all rural Secondary Roads.

The severity index and severity rate presented in TABLE 4 aie statistics commonly used by
MDT as measuies of tlie overall severity of accidents on a road segment or route based on the
number and degree of injuries recorded during a given time period.

TABLE 4: Accident Summary (1 991 -2001 )
Canyon Ferry Road Corridor (RP 1.000 to RP 9.241)

Section (RP 1.00 to 4.20)

Rural Section
(RP 4.201 to 9.241)

Total Number of Accidents



Number of Fatal Accidents
(# fatalities)



Number of Injury Accidents
(# injuries)


23 (29)

Number of Properly Damage Only
(PDO) Accidents



Accident Rate (All Vehicles)



Severity Rate



Severity Index



Notes: "lujury" accidents include those crashes with incapacitating, non-incapacitating, and other injuries.
Statistics based on accidents that occuired on route from October 1, 1991 to September 30, 2001.

The severity mdex is a ratio of crashes weighted by severity to the total number of crashes and is
expressed by the foUovvdng formula.

Severity Index = 8t#ofK+A crashes) +3t# of B + C crashes) + 1(# of O crashes)

Total # of crashes

K = crash with fatahty

A = Clash with incapacitating injury B = crash with non-inciqiacitating injury
C = crash with possible injury O = crash with propeily damage only

The severity late is the number of crashes weighted by severity per million vehicle miles. The
severity late is calculated by multiplying the accident crash rate times the severity index.

The accident severity mdices foi the commercial/residential and the nual section of Canyon
Feny Road were calculated to be 2.38 and 2.50, lespectively. These figures compare closely to
tlie statewide average accident severity index of 2 . 44 for all nual Secondaiy Roads in Montana.
The severity rates for the commercial/residential and the niral section of Canyon Feny Road
were calculated to be 13.42 and 3.65, respectively, for the 1991-2001 period. These flguies
compaie to a statewide average severity rate of 4.31 for state luial Secondary roads. The severity
rate for the commercial/residential section is moie than tiuee times greater than tiie statewide
average severity late.
A review of the characteristics and contributing factors to motor vehicle accidents occuiring


Canyon Ferry Road: STPS 430-1(5} 1 Environmental Assessment

witliin the Canyon Feriy Road project corridor duiing a the ten-year study period identified the
following variations from average statewide occmrences for all nual secondary routes:

Canyon Ferry Road - Commercial Residential Section (RP 1 .0 to RP 4.2)

73.7% on roadway accidents vs. 47.7% statewide.
82.4%i dry road accidents vs. 65.1% statewide.
67.6% daylight accidents vs. 52.5% statewide.
24.3% rear-end collisions vs. 7.9% statewide.
31.1% right-angle coUisions vs. 9.7% statewide.

Canyon Ferry Road - Rural Section (RP 4.201 to RP 9.241 )

28.9% icy road collisions vs. 18.4% statewide.
19.2% rear-end collisions vs. 7.9% statewide.

A review of the accident data also revealed tlie followir^:

Alcohol was a factor in 7 percent of all the reported accidents on Canyon Feny
Road over the 1991 tliiough 2001 period.

Five percent of the recorded accidents during the study period involved domestic
or wild anunals.

Along the commercial/residential section of Canyon Feny Road (RP 1.000 to 4.200), the
accident tiend is collisions between moving vehicles. Of the 148 recorded crashes in this
section, 100 (67.6%) were coded as "in intersection", "intersection related", "in driveway access"
or "driveway related." In 58 of tlie 148 recorded accidents in tliis section of the project area, at
least one of the vehicles intended to tiun. Based on the data, the greatest concentration of
intersection-related accidents occurred at tlie intersection of Canyon Feny Road and Valley
Drive. Of tlie 27 accrdents that were reported at this locatron during the 1991-2001 period, 19
were right-angle coUisions, 3 were rear-end coUisions, and 2 were sideswrpes. One accident
involved a coUisron between a motorrst and bicyclist.

Within the rural section of the project corridor, accrdent data reveals a concentration of off-road
crashes at the curve near reference post 7.4. Additionally, the data shows a concentiation of
crashes near' and at tlie intersection witli Spokane Creek Road at the east end of the project,
including a fatal crash.

Theroadwidening, improved sight distance, slope flattening, provrsion of turn lanes, access
management, lighting and delineation, and intersection reconfiguratrons associated with this
proposed lirghway improvement project should substantially improve traffic safety in the Canyon
Ferry Road corridor.

P. Legislation Mandating Action


Canyon Ferry Road: STPS 430-1(5} 1 Environmental Assessment

The 56"' Montana Legislature made major changes to Montana's Secondary Highway Program
during the 1 999 session. The signing of Senate Bill 333 mto law changed the long-standmg
Secondary Program and required MDT to assmne maintenance responsibility for all paved
Secondary Routes. Some Secondary Roads that are either gravel or not sufficiently paved do not
fall under the maintenance directive from tlie Legislature.

MDT's newly delegated maintenance responsibilities on Secondary Routes like Canyon Ferry
Road includes: winter maintenance, pavement mamtenance, striping and signing, the
maintenance of safety devices, and maintenance of diainage and roadside activities. This means
MDT is obligated to maintain, preserve and enhance (if needed) tlie roadway and associated
facihties to ensure continued and safe use by the tiavehng public. Even if improvements were
not proposed or being investigated for Canyon Ferry Road, MDT is obligated to ensure that
travel on the route can be accomphshed m a safe and efficient manner.

E. Overall Conclusions on Need

The existing roadway and bridges have many physical deficiencies that contribute to leduced
safety for users of Canyon Feny Road. Several of these deficiencies are related to the roadway's
original design and can be coirected only through reconstruction.

Reconstructing tliis segment of Canyon Ferry Road would substantially improve safety by
bringing the design of the highway into compliance with MDT's current design standards for
Rural Major Collectors with desrgn speeds of 90 km/li (55 mph) for the road's
commercral/residential section and 80 km/li (50 mph) for its rural section. The width of the
roadway's surface would increase fiom 7.2 m (24 feet) to at least 12.0 m (40 feet) to include
shoulders. Desuable stopping sight distance would be provided at substandard vertical curves
and deficient horizontal curves would be rebuilt to meet the criteria foi the design speed. The
new bridges associated with tiiis proposed actron would be wrder than existing stiuctiires and
have mcreased load carrying capacrties.

Many of the road's intersections would be redesigned to accommodate left-turn lanes to help
keep tiaffic flowing and enliance safety. Othei safety enliancements for the project include
widened shoulders for the occasional bicyclists and continued roadside mail delivery on the
route, the addition of roadway hghtmg at major mtersectrons; a tiaffic signal at Wyhe Drive;
flasliing beacons, tiansverse nunble strips on major intersecting road approaches; shoulder
nunble strips m the rural segments; and appropriate signmg and delineation tliioughout tire
pioject corridor.


Canyon Ferry Road

STPS430-ifSJ i/ Control No. 4480

En vironmen tal Assessmen t


Canyon Ferry Road; STPS 430-1(5) 1

Environmental Assessment

. Alternatives Considered

A. Introduction

This Part describes tlie alternatives considered to address the transportation and other needs
identified in Part II. Alternatives are the various activities or actions that could be implemented
by MDT to meet the purpose and tire need for improving Canyon Feiiy Road between RP 1 .2
and RP 9 . 6 and improving a portion of Spokane Creek Road near the east terminus of tiiis
proposed project.

As indicated earlier in this EA, MDT's Canyon Feiiy Road project would reconstruct 13.6 km
(8.4 miles) of S-430 and a portion of Spokane Creek Road (S-284) near its mtersection with
Canyon Feny Road. A variety of prelimmary engineering activities and stiidies have been
completed to establish the use and condition of tire existing facihty and to evaluate how the
piesent load complies witii MDT's design standar'ds for Rmal Collectors with design speeds of
80 km/li (50 mph) and 90 km/h (55 mph). The "action" alternatives considered for this proposed
project are comprised of actions to eliminate deteriorated conditions and replace substandard
roadfeatiires; enliance the overall safety and efficiency of the liighway; and measures to ensure
file reconstnicted liighway is responsive to its current and fiituie roadside environment and uses.

This Part describes the proposed improvements that comprise the Preferred Action. The
"Preferred Action" is tire alternative tiiat MDT believes would best meet tire purpose and need
for the project, giving consideration to economic, environmental, technical factors, and pubHc
sentiment. This Part also identifies otiier alternatives initially considered by MDT for the
Canyon Ferry Road reconstruction project and discloses reasons for tiie rejection of such

The alternative of taking no action to improve Canyon Ferry Road is also considered here. The
No Action alternative does not meet the purpose and need for the project as described in Part II
and has been rejected fiom fuitiiei consideiation. The No Action alternative does, however,
provide a baseline against wliich the Preferred Action (or other alternatives) can be compared.
The environmental effects of the No Action alternative will be discussed in Part IV as a means of
comparing and contrasting tiie impacts of MDT's Piefeixed Action.

B. No Action Alternative

The No Build alternative (also knovm as the "do notiiing" alternative) involves taking no major
action to improve or change Canyon Feny Road. MDT would mamtain and repair the road and
its associated features as needed (and as economically feasible) to ensure contmued public use.

However, tins alternative would not improve the horizontal or vertical alignment of the highway,
increase the width of the roadway, replace substandard bridges, or include any measures to
respond to identified traffic safety oi operational concerns. The geometiic layout and sight


Canyon Ferry Road; STPS 430-1(5) 1 Environmental Assessment

distance problems at the intersection of Canyon Ferry Road and Spokane Creek Road would not
be addressed. The liighway woiild continue to be substandard based on MDT's geometric design
criteria for Non-NHS Secondary Rural Collector Roads for the amount of tiafQc using the route.

As the condition and operation of Canyon Feny Road continue to deteiiorate, it will become
incieasiiigly difficult foi its useis to leach tlieu homes, places of business oi recreational areas
served by tlie load. Taking no action may affect tlie safety of the tiaveling public due to
incieased traffic on a route with deteriorated road conditions and inherent geometric design

Drivers may mdirectly inciu' otliei costs with the No Build Alternative, including automobile
damage or more fiequent mamtenance due to poor road conditions, travel delays and mcreased
fliel consmnpti on because of traffic congestion, and damages (costs associated with property
damage and personal injuries) if accident numbers or seventies rise.

The remainmg costs associated with this alternative would be those associated with
implementing maintenance activities and repairing the roadway and its associated features. Other
tiian mmoi, temporary and locahzed adverse environmental effects, tire No Build Alternative
would not cause any new impacts to tiie surrounding environment. There would be no new
impacts on adjacent commercial or residential pioperties or agncultiiral lands since this
alternative would not change access to adjoining lands oi requue the acqmsition of any new

C. Preferred Action/Associated Improvements


The Prefened Action is to reconstruct Canyon Ferry Road fiom about RP 1.2, Walter Drive, to
just east of the mtersection of Canyon Ferry Road and Spokane Creek Road at about RP 9.6.
Transitions to and fiom existing roadways east and west of the project area would be required.
The pioposed reconstiuction project would vvdden the existing two-lane facihty to include paved
shoulders, turn lanes where appropriate, improve the geometiic layouts of major intersections
and alter tire road's grade and alignment to provide desirable sight distances tlnoughout the
project corridor. Reconstiuction of Canyon Feny Road would require development of detailed
design and right-of-way plans and the pieparation of an access contiol plan for the project area.

Montana liighways and bndges are designed to meet or exceed recommended minunum
geometric standards. These geometric standards are based on design policies and guidelines
established by MDT and AASHTO. MDT would develop and design tire liighway improvements
to confoim to MDT's "Road Design Manual" and "Bridge Design Standaids" and AASHTO's
Standard Specifications.

Site preparation work would include right-of-way acquisition, utility relocation, and clearing and
grading. Drainage stmctures with adequate roadside ditches to accommodate runoff from the
roadway would be installed and slopes would be stabihzed and revegetated. Curbs and gutters


Canyon Ferry Road; STPS 430-1(5) 1 Environmerital Assessment

would be installed along the roadway withm the commercial/residential section of the corridor
and minimal width ditches would typically be provided adjacent to the highway to convey nuioff
in the rural section of the corridor. New fences would be installed tliioughout tire nual section of
tlie corridor at new right-of-way limits.

New right-of-way would be acquired over the lengtli of the project and conflicting utilities would

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Online LibraryRobert Peccia & AssociatesEnvironmental assessment and nationwide section 4(f) evaluation Canyon Ferry Road : STPS 430-1(5)1; CN 4480, Lewis and Clark County, Montana (Volume 2003) → online text (page 3 of 19)