United States 

Department of 

Agriculture 

I 

Forest Service 

Northeastern Forest 

Experiment Station 

Research Paper NE-665 

Cost Estimators for 

Construction of Forest Roads 

in Central Appalachians 

Deborah A. Layton 

Chris B. LeDoux 

Curt C. Hassler 
Abstract 

Regression equations were developed for estimating the total cost of road construction in the central Appalachian region. Estimators include methods for predicting 

total costs for roads constructed using hourly rental methods and roads built on a 

total-job bid basis. Results show that total-job bid roads cost up to five times as 

much as roads built when equipment is rented hourly. The estimates presented are 

for well-drained, stone-surfaced, permanent, minimum- to high-standard roads. 

The Authors 

DEBORAH A. LAYTON is currently a private consultant, and was a graduate 

student at West Virginia University at the time this research was conducted. 

CHRIS B. LEDOUX is a supervisory industrial engineer with the Northeastern Forest 

Experiment Station at Morgantown, West Virginia. 

CURT C. HASSLER is Director of the Appalachian Hardwood Center at West 

Virginia University at Morgantown. 

-- 

Manuscript received for publication 11 May 1992. 

Northeastern Forest Experiment Station 

5 Radnor Corporate Center 

100 Matsonford Road, Suite 200 

P.O. Box 6775 

Radnor, Pennsylvania 19087-4585 

July 1992 
Introduction 

The construction of forest roads is the most expensive and 

time-consuming task involved in forest operations. Road 

construction costs are difficult to estimate because of the 

variability of terrain, soils, rock outcrops, machinery used, 

special design features, and other factors (Koger 1978; 

Kochenderfer et al. 1984; Ou and Swarthout 1984; Layton 

1990). There is a need for cost-prediction methods that 

can be used in conjunction with other stand- and forestlevel planning models. Ideally, road cost models should be 

developed in such a way that they can be used to estimate the cost of a given road section and also in combination with other algorithms as a forest management 

planning tool. 

In this paper we investigated the factors that have a major 

impact on the cost of forest road construction in the 

central Appalachians, and developed equations that will 

enable planners to estimate the cost of constructing roads 

to different standards for the central Appalachians. (Central 

Appalachians refers to the mountainous sections of 

Pennsylvania, Maryland, Virginia, and West Virginia.) Our 

objective was not to compare one method or variable with 

another. Rather, the data presented here is representative 

of well-drained, stone-surfaced, permanent, minimum- to 

high-standard roads that were constructed on similar site 

conditions in the central Appalachians. 

Table l.-Sources for the roads constructed on an 

hourly rental basis 

Source 

Number 

of roads 

Monongalia County ASCS 

Nicholas County ASCS 

Allegheny National Forest 

Monongahela National Forest 

Maryland State Forests 

West Virginia State Forests 

Pennsylvania Department of 

Environmental Resources 

Private Forest Industry 

Literature (Monongahela National Forest) 

Total 

Methods and Procedures 

Road construction data were divided into two groups: 

Group I included roads built with equipment rented on an 

hol~rly basis. Group II included roads built under a total-job 

bid system. Cost data for forest road construction were 

compiled for 57 roads (76 miles) constructed using hourly 

rental equipment and 67 roads (172 miles) constructed on 

a total-job basis. All of the Group II roads studied were 

constructed on the Monongahela National Forest in West 

Virginia. Data collected included when and where the road 

was constructed; slope position; sidehill percent slope; 

aspect; length; design speed; soil and rock types; road 

grade; laborer and foreman hours and cost; machine 

hours; type; and cost per hour; road-surfacing types; 

quantities; and cost per ton; drainage structures installed 

(type, size, cost/foot); cleared and surface width; average 

annual precipitation; vehicles per day using the road; 

postharvest treatment, and cost; and estimated savings for 

the next harvest if the road was reused. Hourly rental data 

were compiled from state, national, industry, and private 

practitioners (Table 1). Some data were collected at the 

headquarters of the Monongahela National Forest in Elkins, 

West Virginia, and at the Nicholas County ASCS office in 

Summersville, West Virginia. 

The data sets for Group I and II roads were used independently to develop regression equations for estimating total 

road construction costs. We also used a subset of 30 

Group I roads and 40 Group II roads. Many roads for both 

data sets were eliminated due to outliers, missing data, 

and inconsistencies in the reported results. SAS CORR 

procedures were used to examine relationships between 

the variables and road construction cost. The SAS 

RSQUARE option of the SAS REG procedure was used to 

determine those combinations of independent variables 

with the best coefficient of determination (R2) and most 

closely approached a Mallow's C(p) statistic equal to the 

number of variables included in the model. Finally, the 

SAS REG procedure was used to develop the individual 

equations and to conduct a residual analysis to detect any 

nonhomogeneity of variables and nonlinearity. 

Table 2.-Descriptive Statistics for hourly rental roads 

Variable Average Range 

Put-to-bed cost (includes water 

bars and seeding) (dollars) 148 0 to 3,784 

Cleared width (similar to acres 

cleared) (acres) 24 0 to 50 

Culvert length (feet) 166 0 to 640 

Percent sideslope 24 5 to 47 

Percent grade (finished road surface) 7 4 to 15 

Quantity of surfacing material (tons) 968 0 to 6,600 

Results 

Hourly Rental Data 

For the Group I data set, the average road length was 
1.27 miles (range: 0.20 to 4.60). The average road width 

was 13.7 feet (range: 12 to 18). Bulldozers used to 

construct Group I roads ranged in horsepower from 46 to 

310 with an average of 132. The total road cost ranged 

from $1,363 to $94,342 (average: $1 1,104). Other averages and ranges are shown in Table 2. Table 3 shows the 

average total cost of road construction by location. 

Table 3.-Average total cost of construction by 

location for hourly rental roads 

Location Costlmile 

Monongalia ASCS District 

Maryland Dep. Nat. Resour. 

PA Dep. Environ. Resour. 

Penn.-Va. Corp. 

Nicholas ASCS District 

Monongahela National Forest 

West Virginia Dep. Nat. Resour. 

Dollars 

3,052 

5,471 

10,379 

2,500 

5,978 

9,891 

11,128 

Although we began with about 20 independent variables 

and many variables were highly correlated with total roadconstruction cost, the collinearity between some of the 

variables and the degree of difficulty in measuring some of 

them prior to road construction resulted in their exclusion 

from the model (Layton 1990). The cost equation selected 

for hourly rental roads 

SQRT(Y,) = 34.801 + 36.167 * X, + 0.095 * X2 (1) 

R2 = 79.0 percent 

where: SQRT = square -root 

Y, = total road construction cost, dollars 

XI = length of road, miles 

X, = dozer horsepower, integer 

It is interesting to note that the regression coefficient for X2 

(dozer horsepower) indicates that total road cost increases 

with increasing dozer sizehorsepower. This refutes the 

commonly held belief that using a larger dozer saves so 

much time that the higher cost per hour is offset. For 

forest roads constructed in the central Appalachians, 

substantial savings probably could be realized by using the 

smallest dozer capable of doing the job; though certain site 

conditions might require a larger dozer for grubbing and 

excavating. 

Total Job Bid Data 

For Group II roads, the average road length was 1.98 

miles (range: 0.1 to 5.7). The average length of culverts 

used was 461 feet (range: 0 to 1930). The average 

number of acres seeded (roadbanks, etc.) was 2.3 (range: 

0 to 8.6). The average total cost for this set of roads was 

$68,385 (range: $4,537 to $197,584). Other averages and 

ranges are shown in Table 4. The cost equation selected 

for total-job bid roads was: 

R2 = 94.8 percent 

where: 

Y, = total road construction cost, dollars 

X, = length of road, miles 

X2 = area seeded, acres 

XB = total length of culverts, feet 

0.2 0.6 1.0 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 

Road Length [miles] 

Figure 1 .-Total costs for roads constructed using hourly rental methods. 

2 
Road Length (miles] 

Figure 2.-Total costs for roads constructed using total-job bid methods (average seeded acres = 2.3). 

Table 4.-Variables for total-job bid roads 

Variable Average Range 

Acres cleared (no.) 5.42 0 to 17.1 

Surfacing (tons) 1004.33 0 to 4400 

Gates (no.) 0.40 0 to 2 

Hiprap (tons) 6.46 0 to 25.4 

Seeded acres (no.) 2.31 0 to 8.6 

Signs (no.) 0.63 0 to 4 

Culvert (feet) 460.77 0 to 1930 

Road length (miles) 1.98 0.1 to 5.7 

Percent sideslope 31.93 0 to 45 

Total 68385.07 4537 to 197584 

Discussion 

Equations 1 and 2 were used to develop Figures 1 and 2. 

Total cost for hourly rental construction increases with 

length of road built and with increasing horsepower (Fig. 

1). Total cost for total-job bid construction increases with 

length of road built and increasing area seeded, and total 

length of culverts (Fig. 2). In the central Appalachians, it 

costs up to five times as much to build a road that is bid 

on in total than when equipment is rented hourly. One 

reason for this difference is that Davis-Bacon wage rates 

must be paid for any contracted government project. These 

rates vary from state to state and even from county to 

county, and are often three to five times higher than those 

for independent equipment operators as they are based on 

union wages for an area. Also, hourly rental roads require 

only about one-third as much culvert pipe as total-bid 

roads. More culvert pipe also requires more ditching and 

excavation. And total bid roads generally require more 

gates, riprap, signs, etc. than hourly rental roads. However, 

the effect of increasing horsepower on total cost is 

relatively small. For example, the total cost for 50- and 70- 

hp dozers at 0.2 mile is $2,188.78 and $2,370.1 7, 

respectively or an increase of about 8.3 percent. By 

contrast, the cost for 50- and 90-hp dozers at 0.2 mile is 

$2,188.78 and $2,558.78, respectively, an increase of 

about 17 percent (Table 5). The total cost by horsepower 

class decreases with increasing road length because setup 

costs are spread over more miles of construction. For 

example, the total cost for 50- and 70-hp dozers at 4.6 

miles is $42,402.71 and $43,188.81, respectively, a 

difference of only 1.85 percent. Clearly, for short segments 

of road construction (fewer than 2.5 miles), one would 

generally enjoy a cost advantage by using the smallest 

dozer capable of doing the job. The total cost of a 2.5-mile 

road segment with 2.3 acres seeded and no culverts is 

$57,989.03. By contrast, the same segment, seeded the 

same and with 522 feet of culverts is $79,371.80, an 

increase of about 37 percent. 

Use of Estimators 

The equations for Group I and Group I1 roads can be used 

3 
Table 5.4ncremental construction costs for hourly rental roads, by length of road built and dozer horsepower 

Road 

length Horsepower 

(miles) 50 70 90 110 130 150 170 190 210 230 250 270 290 310 

by managers, planners, loggers, and contractors to 

estimate road-building costs; and in evaluating alternative 

silvicultural treatments where road building is required. The 

estimators can be integrated with system models to 

evaluate the impact of road building costs on entry timing 

and forest management. 

Individual point estimates can be obtained by substituting 

the desired values in the equations. For example, say one 

wishes to develop total costs for a I-mile road segment 

using a 80-hp dozer. For hourly cost rental we have 

SQRT (Total cost) = 34.801 + 36.167 * (1) + 

0.095 * (80) 

= 78.568 

(Total cost) = (78.568)2 

= $61 72.93 

For the same road with no culvert, no seeding, and totaljob bidding we have 

(Total cost) = 1740.879 + 14433.181 * (1) + 

8767.48 * (0) + 38.765 * (0) 

(Total cost) = $1 6,174.06 

Thus, the total bid road costs about 162 percent more 

than the hourly rental road. 

These equations are based on data that represent similar 

road-construction conditions in the central Appalachians. 

As stated earlier, the statistical analysis eliminated many 

independent variables and resulted in equations with 

different variables. Our intent was not to compare the two 

methods of road construction but to provide methods for 

estimating the total cost of road construction by financing 

method. These results can be used in conjunction with 

other stand- and forest-level planning models. 

Literature Cited 

Kochenderfer, J. N.; Wendel, G. W.; Smith, H. Clay. 1984. 

Cost of and soil loss on "minimum-standard" forest 

truck roads constructed in the Appalachians. Res. 

Pap. NE-544. Broomall, PA: U.S. Department of 

Agriculture, Forest Service, Northeastern Forest Experiment 

Station. 

Koger, Jerry L. 1978. Factors affecting the construction 

cost of logging roads. Tech. Note 827. Norris, TN: 

Tennessee Valley Authority, Division of Forestry, Fisheries, 

and Wildlife Development. 

Layton, Deborah A. 1990. Forest road construction cost 

equations for the central Appalachians. Morgantown, 

WV: West Virginia University. M.S. thesis. 

Ou, Fong L.; Swarthout, Colburn D. 1984. Cost 

estimating model for forest roads. In: Proceedings, 64th 

annual meeting of the Transportation Research Board; 

1984; Washington, DC. Washington, DC: Transportation 

Research Board. 
I Layton, Deborah, A.; LeDoux, Chris 0.; Hassler, Curt C. 1992. Cost estimators for construction of forest roads in the central Appalachians. Res. 

I Pap. NE-665. Radnor, PA: U.S. Department of Agriculture, Forest Service, 

Northeastern Forest Experiment Station. 4 p. 

Regression equations were developed for estimating the total cost of road 

construction in the central Appalachian region. Estimators include methods for 

predicting total costs for roads constructed using hourly rental methods and 

roads built on a total-job bid basis. Results show that total-job bid roads cost 

up to five times as much as roads built than when equipment is rented hourly. 

The estimates presented are for well-drained, stone-surfaced, permanent, 

minimum- to high-standard roads. 

Keywords: Forest roads, minimum standards, regression equations 

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