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HERS-ST Highway Economic Requirements System - State Version: Technical Report

Chapter 6 Capital Cost of Improvements

HERS requires estimates of highway improvement costs to be included in the analysis of investment options. In the case of the pavement, widening and alignment improvements currently considered by HERS, these costs are all initial costs; i.e., they are incurred at the time the improvement is implemented. When analyzing the economic attractiveness of a potential improvement, the improvement cost is used as the denominator in the benefit-cost equation.

This chapter contains six parts. The first discusses how HERS divides the section into the portion receiving improved alignment (if any) and the portion receiving the identified improvement.

The second part presents the HERS procedure for estimating the initial cost of each of the HERS-type improvements.

The third part explicates the HERS procedure for estimating the initial cost of improvements which include a modified alignment.

The fourth section presents the process for combining the costs with and without alignment modification to determine the total cost of improving a section.

The fifth part of this chapter discusses the allocation of improvement costs between preservation and expansion.

The final portion of this chapter presents the state cost factors which (optionally) adjust the cost of improvements by state.

6.1 The Length of an Improvement

On sections receiving an alignment improvement, HERS only improves alignment over that portion of the section with deficient alignment. HERS improves the rest of the section with the specified improvement. Thus HERS identifies three lengths for sections undergoing improvement:

  • SLEN - the length of the section (HPMS item 30);
  • LNEW - the length of the portion of the section being re-aligned; and
  • IMPLEN - the length of the section which will receive the specified improvement.

HERS identifies the length of the section to be re-aligned (LNEW) as:

Eq. 6.1

LNEW = LAFTV × OPTV + LAFTH × OPTH

where:

LAFTV = length of corrected grades after re-alignment;
LAFTH = length of corrected curves after re-alignment;
OPTV = 1 if grades are being corrected by re-alignment, 0 otherwise; and
OPTH = 1 if curves are being corrected by re-alignment, 0 otherwise.

The PreProcessor determines the two values LAFTV and LAFTH when processing the section's geometrics. HERS limits LNEW to be less than or equal to SLEN. The length of the section to be improved without re-alignment (IMPLEN) is:

Eq. 6.2

IMPLEN = SLEN LNEW

6.2 Pavement and Widening Improvements

HERS distinguishes nine elemental improvement costs, two of which are for improved alignment. Table 6-1, "Elemental Capital Improvement Costs," presents the scaled estimates of HERS improvement costs per lane-mile. These costs are national averages expressed in 2002 dollars but can be scaled to any other-year dollars by the user. The HERS costs include both improvement and right-of-way (ROW) costs, but do not include costs such as unusual cut and fill operations, excessive number of structures, or non-construction costs.

When adding lanes or re-aligning pavement, HERS distinguishes between costs incurred at "normal" and "high" cost. The cost level is determined by the interaction between each section's widening feasibility code (WDFEAS, HPMS item 62) and the section's functional class' widening feasibility override code. (For a more detailed discussion, see section 4.3, "The Widening Feasibility Model," page 4-26.) While under certain circumstances HERS will add both normal and high cost lanes in a single improvement, if any high cost lanes are added to a section HERS will perform any re-alignment on that section at high cost.

Three of the costs (for shoulders and the two add lanes costs) are incremental: that is, they are added to other improvements costs when costing the improvement.

6.2.1 Resurfacing Pavement

HERS computes the cost of resurfacing a section as:

Eq. 6.3

RSCost = IMPLEN × XLANES × DHwyGrp

where:

RSCost = the cost of the resurfacing improvement;
IMPLEN = the length of the improvement;
XLANES = the number of existing lanes; and
DHwyGrp = the lane-mile cost to resurface, from column D of Table 6-1, with the row determined by the section's Highway Group.
Table 6-1. Elemental Capital Improvement Costs (Thousands of 2002 Dollars per Lane-Mile)
  A B C D E F G H I
  Reconstruct and Widen Lanes Reconstruct Pavement Resurface and Widen Lanes Resurface Pavement Improve Shoulders Add Lane at Normal Cost Add Lane at High Cost Re-Align Pavement at Normal Cost Re-Align Pavement at High Cost
Rural Interstate
Flat terrain 1182 772 669 274 51 1899 2633 2106 10948
Rolling terrain 1325 792 770 292 84 2059 3331 2665 11444
Mountainous terrain 1564 916 927 322 129 2638 8315 3120 12458
Rural Other Principal Arterials
Flat terrain 923 618 558 220 34 1521 2178 1742 8882
Rolling terrain 1042 635 634 245 57 1629 2629 2103 9396
Mountainous terrain 1197 720 739 267 89 1981 7368 12000 12000
Rural Minor Arterials
Flat terrain 844 543 520 195 32 1383 1941 1553 1553
Rolling terrain 1019 601 647 210 59 1585 2500 2000 2000
Mountainous terrain 1182 687 761 232 90 1951 7368 11500 11500
Rural Major Collectors
Flat terrain 889 575 537 199 41 1436 1436 1553 8838
Rolling terrain 973 584 604 211 55 1468 1468 1910 10054
Mountainous terrain 1111 662 699 231 87 1730 6911 11000 11000
Urban Interstate, Other Freeways and Expressways
Small Urban 1987 1376 1566 334 61 3116 11094 5235 13290
Small Urbanized 2136 1388 1620 395 81 3405 12121 5720 14939
Large Urbanized 3407 2272 2509 530 306 5699 60000 9574 60000
Urban Other Principal Arterials
Small Urban 1732 1169 1433 280 62 2649 9430 4450 11131
Small Urbanized 1853 1183 1498 331 83 2870 10218 4822 12401
Large Urbanized 2647 1734 2192 416 267 4200 14953 6216 14288
Urban Minor Arterials and Collectors
Small Urban 1276 883 1084 205 45 1956 6964 3287 8929
Small Urbanized 1337 893 1094 233 55 2061 7338 3463 10003
Large Urbanized 1800 1194 1496 286 150 2858 10173 4801 11179
6.2.2 Resurfacing Pavement with Shoulder Improvements

HERS computes the cost of resurfacing a section and improving shoulders as:

Eq. 6.4

RSSHCost = IMPLEN × XLANES × DHwyGrp +
IMPLEN × EHwyGrp × FT

where:

RSSHCost = the cost of the resurfacing with improved shoulders improvement;
IMPLEN = the length of the improvement;
XLANES = the number of existing lanes;
EHwyGrp = the center-line mile cost to improve the shoulder on one side of the highway, from column E of Table 6-1, with the row determined by the section's Highway Group; and
FT = 1 for one-way facility, 2 for two-way facility.
6.2.3 Resurfacing Pavement and Widening Lanes

As this improvement can be implemented with or without shoulder improvements, HERS uses either of these two algorithms to calculate the cost. When shoulders are not being improved:

Eq. 6.5

RSWLCost = IMPLEN × XLANES × CHwyGrp

where:

RSWLCost = the cost of resurfacing an widening lanes; and
CHwyGrp = the lane-mile cost to resurface with wider lanes, from column C of Table 6-1, with the row determined by the section's Highway Group.

When shoulders are also being improved, HERS uses:

Eq. 6.6

RSWLCost = IMPLEN × XLANES × CHwyGrp +
IMPLEN × EHwyGrp × FT

where all terms are as defined above.

6.2.4 Resurfacing Pavement and Adding Normal Cost Lanes

HERS uses one of four possible algorithms when costing this improvement depending upon whether lane width and shoulders (or both) are being included in the improvement. The simplest algorithm is when neither lane width or shoulders are being improved:

Eq. 6.7

RSNCCost = IMPLEN × XLANES × DHwyGrp +
IMPLEN × NCLADD × FHwyGrp

where:

RSNCCost = the cost of resurfacing and adding normal cost lanes;
NCLADD = the number of normal cost lanes being added; and
FHwyGrp = the lane-mile cost to add a lane at normal cost, from column F of Table 6-1, with the row determined by the section's Highway Group.

When the shoulders are to be improved, HERS uses:

Eq. 6.8

RSNCCost = IMPLEN × XLANES × DHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × EHwyGrp × FT

When the existing lanes are to be widened (but shoulders not improved) HERS uses:

Eq. 6.9

RSNCCost = IMPLEN × XLANES × CHwyGrp +
IMPLEN × NCLADD × FHwyGrp

thus substituting the base cost of resurfacing with wider lanes for simple resurfacing.

And when the section is to be resurfaced with wider lanes and shoulder improvements, and additional lanes added at normal cost, HERS uses:

Eq. 6.10

RSNCCost = IMPLEN × XLANES × CHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × EHwyGrp × FT

using the base cost of resurfacing with wider lanes plus the cost of adding lanes plus the cost of shoulder improvements.

6.2.5 Resurfacing Pavement and Adding High Cost Lanes

The HERS algorithms for adding high cost lanes are the same as those for normal cost lanes with the addition of high cost lanes as an additional charge. This accommodates improvements which add lanes at both normal and high cost. If no normal cost lanes are added, then NCLADD is zero.

For simple resurfacing and adding lanes, some at high cost, HERS calculates:

Eq. 6.11

RSHCCost = IMPLEN × XLANES × DHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp

where:

RSHCCost = the cost of resurfacing and adding high cost lanes; and
GHwyGrp = the lane-mile cost to add a lane at high cost, from column G of Table 6-1, with the row determined by the section's Highway Group.

When shoulders are to be improved, HERS uses:

Eq. 6.12

RSHCCost = IMPLEN × XLANES × DHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp +
IMPLEN × EHwyGrp × FT

When the existing lanes are to be widened without shoulder improvements, HERS calculates:

Eq. 6.13

RSHCCost = IMPLEN × XLANES × CHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp

And when existing lanes are widened, shoulders are improved, and lanes added at high cost, HERS uses:

Eq. 6.14

RSHCCost = IMPLEN × XLANES × CHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp +
IMPLEN × EHwyGrp × FT
6.2.6 Reconstructing Pavement

HERS determines the cost of reconstructing existing pavements as:

Eq. 6.15

RCCost = IMPLEN × XLANES × BHwyGrp

where:

RCCost = the cost of reconstructing pavement; and
BHwyGrp = the lane-mile cost to reconstruct pavement, from column B of Table 6-1, with the row determined by the section's Highway Group.

When HERS reconstructs pavements, it improves the shoulders to the design standard if necessary. HERS does not identify or cost "reconstruction with shoulder improvements" as a separate improvement type.

6.2.7 Reconstructing Pavement and Widening Lanes

HERS calculates the cost of reconstructing pavement and widening the existing lanes as:

Eq. 6.16

RCWLCost = IMPLEN × XLANES × AHwyGrp

where:

RCWLCost = the cost of reconstructing pavement and widening the existing lanes; and
AHwyGrp = the lane-mile cost to reconstruct pavement with wider lanes, from column A of Table 6-1, with the row determined by the section's Highway Group.
6.2.8 Reconstructing Pavement and Adding Normal Cost Lanes

When reconstructing pavement and adding lanes at normal cost, HERS uses:

Eq. 6.17

RCNCCost = IMPLEN × XLANES × BHwyGrp +
IMPLEN × NCLADD × FHwyGrp

where:

RCNCCost = the cost of reconstructing pavement and adding lanes at normal cost.

When the existing lanes are to be reconstructed and widened, and new lanes are to be added at normal cost, HERS calculates:

Eq. 6.18

RCNCCost = IMPLEN × XLANES × AHwyGrp +
IMPLEN × NCLADD × FHwyGrp
6.2.9 Reconstructing Pavement and Adding High Cost Lanes

HERS costs pavement reconstruction and the addition of lanes at high (and possibly normal) cost as:

Eq. 6.19

RCHCCost = IMPLEN × XLANES × BHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp

where:

RCHCCost = the cost of reconstructing pavement and adding lanes at high cost.

When the existing lanes are to widened as well as being reconstructed, HERS uses:

Eq. 6.20

RCHCCost = IMPLEN × XLANES × AHwyGrp +
IMPLEN × NCLADD × FHwyGrp +
IMPLEN × HCLADD × GHwyGrp

6.3 Calculating Alignment Costs

HERS performs re-alignment only on that portion of a section which is reported as deficient in alignment.

As with improvements which add lanes, HERS performs alignment improvements at either normal or high cost dependent upon each section's widening feasibility code (WDFEAS) and the widening feasibility code override (WDFOVR) for the section's functional class. (See section 4.3, "The Widening Feasibility Model," page 4-26, for details on the widening feasibility mechanism.) Re-alignment is calculated at high cost when a section's WFEAS is one (meaning no widening is possible) or lanes are being added and some of those lanes are at high cost. Otherwise, re-alignment is calculated at normal cost.

To calculate alignment costs on a section, HERS uses:

Eq. 6.21

ALIGNCost = LNEW × ALLLANES × HIHwyGrp

where:

ALIGNCost = the cost of alignment improvement on the section;
LNEW = the length of the section undergoing alignment improvement;
ALLLANES = the total number of lanes on the section after improvement (that is, the sum of the existing lanes and any lanes being added); and
HIHwyGrp = the lane-mile cost to re-align pavement, from columns H (normal cost) or I (high cost) of Table 6-1, with the row determined by the section's Highway Group.

6.4 Total Improvement Cost

For any section, HERS obtains the total initial improvement cost for combining pavement and widening improvements with alignment improvements by combining the cost of reconstructing part of the section on a modified alignment with the cost of the pavement and widening improvements made to the remainder of the section:

Eq. 6.22

TOTIMPCost = (IMPCost + ALIGNCost) × EXPFAC

where:

TOTIMPCost = the total expanded cost of the improvement;
IMPCost = the cost of improving the portion of the section which did not undergo re-alignment (as calculated using equations 6.3 through 6.20);
ALIGNCost = the cost of improving the portion of the section which was re-aligned (using equation 6.21); and
EXPFAC = the section's expansion factor.

6.5 Allocating Capacity and Preservation Costs

During the process of calculating the cost of an improvement HERS allocates the cost between the preservation of existing pavement and the expansion of capacity. HERS allocates the costs as follows (where the columns are those of Table 6-1):

  1. Additional Lanes - The cost of new lanes is allocated to capacity expansion. These costs are calculated using columns F and G.
  2. Widening Lanes - The difference between the base pavement improvement (resurfacing or reconstruction, column B or D) and the same pavement improvement with wider lanes (column A or C) is allocated to capacity expansion. The cost of the base pavement improvement is allocated to preservation.
  3. Improving Shoulders - The cost of improving shoulders (column E) is allocated to preservation.
  4. Pavement Improvement - The cost of improving pavement (column B or D) is allocated to preservation.
  5. Alignment Modification - For the portion of a section receiving improved alignment (columns H and I), HERS prorates the allocation based upon the ratio of new and existing lanes to the total number of lanes.

6.6 State Cost Factors

HERS indexes improvement costs by state. The cost factors are derived from Price Trends1 as a three-year rolling average, and are applied to all capital costs associated with the improvement. For the 2004 C&P Report, all the state cost factors were set to 1.0. Table 6-2 presents the index values used for the 2002 C&P Report (which used 2000 data).


1. Office of Infrastructure, op. cit.


Table 6-2. 2000 State Cost Factorsa
State Factor
a. Source: Derived from FHWA, "Price Trends for Federal-Aid Highway Construction," quarterly.
AL 0.936
AK 1.831
AZ 0.855
AR 0.640
CA 1.262
CO 1.060
CT 1.009
DE 1.349
DC 1.018
FL 1.020
GA 1.091
HI 1.146
ID 0.733
IL 1.159
IN 0.740
IA 0.745
KS 0.765
KY 1.888
LA 1.016
ME 1.541
MD 1.274
MA 1.805
MI 1.324
MN 1.222
MS 1.211
MO 0.846
MT 1.052
NE 0.927
NV 1.019
NH 0.556
NJ 0.771
NM 0.983
NY 1.318
NC 0.911
ND 0.782
OH 1.152
OK 1.054
OR 1.329
PA 1.295
RI 0.840
SC 1.416
SD 0.857
TN 0.929
TX 0.687
UT 0.957
VT 1.232
VA 1.081
WA 1.139
WV 1.196
WI 0.974
WY 0.990
PR 0.725
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Updated: 02/14/2013