Fuel Usage Factors in Highway and Bridge Construction (2013)

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89 Chapter 4 of this report contains two sections. The first section compares the results of the three research methodologies, describes and justifies any modifications, and recommends the final fuel usage factors. The second section presents additional applications of the new fuel usage factors outside of the highway construction industry. 4.1 Comparison of Fuel Usage Estimates This section combines the three different methods of calculating fuel use factors and recom­ mends factors for each of the categories of work described in previous sections. Comparing the various methods of calculating factors allows the study team to develop factors that represent a broad range of methods while also expanding the scope of the factors outlined in the original Technical Advisory T5080.3. This section compares and contrasts estimates of fuel use factors that are available from the various study sources and methodologies. This analysis is performed by major category of work. The major categories of work items are as follows: • Clearing and removal, • Excavation, • Base stone, • Asphalt, • Milling, • Structures, • Miscellaneous concrete, • Drainage pipe and structures/water/sewer, and • Specialty items (fencing/guardrail/landscaping/pavement marking/signalization). For each major category of work, the analysis is divided into two subsections. The first sub­ section presents the study team’s analysis of the fuel use figures developed for each methodology. This analysis considers the following four data sources: 1. Technical Advisory T5080.3. This technical advisory presents the fuel factors calculated for the original 1974 HRB effort. These factors are still used by a large number of contractors and state DOTs. If the fuel factors calculated in the other three methodologies are similar to the figures in TAT5080.3, this will provide a level of validation. If the findings differ, the study team should carefully re­evaluate their assumptions and calculations. 2. Contractor Survey. The Contractor Fuel Usage Survey (CFUS) represents a cooperative effort by the NCHRP, study team, and industry organizations to engage the highway construction C h a p t e r 4 Conclusions, Recommendations, and Future Research

90 Fuel Usage Factors in highway and Bridge Construction contracting community. The objective of this effort was to ascertain fuel use information from contractors representing a broad sample of regions, firm sizes, project locations, and work activities. Utilizing an Excel spreadsheet tool and several iterations of a SurveyMonkey survey, this effort resulted in over 500 data observations. 3. Engineering Analysis. For this methodology, the study team convened an expert panel of veteran construction engineers and estimators. The engineering team first collaborated to rank construction activities by fuel use intensity and recommend items that should be further analyzed. In later efforts, the engineering team then calculated the fuel use for these activities under average project parameters. This was done by calculating the equipment needed for each activity, the fuel consumed by this equipment, production rates, and the average length of time expected to complete each project. The result is a calculation, for each work activity, that expresses the gallons of fuel consumed per a unit of measure, such as the number of gallons of diesel fuel consumed for each linear foot of sewer pipe. 4. BidTabs Statistical Analysis. This experimental methodology attempted to track the relationship between fuel prices and bid estimates. Unlike other elements of a typical construction bid, commodity prices (including fuel) exhibit historical fluctuations due to market variables. This methodology attempted to isolate fuel prices, coalesce them to historical BidTabs data as maintained in the Oman Systems database, and observe any correlations. For each data source, the major category section lists the assumptions that were made and a brief summary of the findings. The concluding subsection provides an analysis of the findings within each category and presents the final recommended factors. The chapter concludes with a summary of the general findings. 4.1.1 Clearing and Removal This subsection presents findings regarding the fuel usage associated with clearing and removal activities. Clearing and removal activities include the clearing of trees and brush, the removal of debris, and the demolition of buildings and structures. Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 lists 200 gallons per acre in “Additional Fuel Usage Factors by States.” There is no listing for any clearing related activities in the main guidelines table. • Survey Results—The number of activities related to clearing and removal items can vary greatly from project to project and region to region. The results of the survey related mainly to the primary “clearing and grubbing” activity. The average of the survey respondents was 194.4 gallons per acre for the clearing tasks. • Engineering Study—The engineering study estimated fuel use for a wide range of activities related to the clearing and removal category. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. The units of measure from the states utilized in the study did not match the units of measure in the survey or the engineering analysis. Exhibit 4­1 presents the fuel use estimates for clearing and removal work items. Based on recommendations from the project review panel, the project team calculated an additional fuel usage factor for a bridge demolition task. The structure demolition assumptions and calculations are provided in Exhibits 4­2 and 4­3.

Conclusions, recommendations, and Future research 91 Conclusion Exhibit 4­4 compares the values from the four different data sources. For comparison purposes, the heavy, medium, and light clearing tasks in the engineering study were combined into an average value, as detail by intensity was available in Technical Advisory T5080.3 or in the survey. Using the values from Technical Advisory T5080.3 and the survey, the project team was able to confirm the values from the engineering study. Based on these favorable results, the detailed results from the engineering study were selected as the final estimates. This is because the engi­ neering analysis provides estimates for a larger number of tasks than either of the other sources. In summary, the team recommends that the engineering study factors be used. 4.1.2 Grading and Excavation This section presents the study findings regarding the fuel usage associated with grading activities. Grading activities involve leveling earth in preparation for the installation of highway and road infrastructure. Task Description Fuel Use Per Unit Units ercA/snollaG 678.821 thgiL – gniraelC ercA/snollaG 954.171 muideM – gniraelC ercA/snollaG 743.372 yvaeH – gniraelC .Y.C/snollaG 793.1 tlahpsA - lavomeR tnemevaP .Y.C/snollaG 265.0 etercnoC - lavomeR tnemevaP .F.L/snollaG 368.0 seziS llA - lavomeR epiP Structure Demolition (House/Building) 375.000 Gallons/Each Structure Demolition (Bridge per S.F. of Deck) 0.626 Gallons/S.F. Exhibit 4-1. Clearing and removal engineering results. Characteristic Assumption Travel Lanes Two lanes, 12 foot width each teef 001 htgneL egdirB hcae teef 6 sredluohS )retnec ,thgir ,tfel( 3 sretooF dnal yrD napS .F.S 006,3 aerA kceD sehcni 01 ssenkcihT kceD Exhibit 4-2. Bridge demolition assumptions. Task Element Quantity Fuel Use Per Unit Fuel Used for Task Element Substructure Demolition 177 C.Y. 1.423 251.871 Gallons Superstructure Demolition 155 C.Y. 1.400 217.000 Gallons Load Haul Debris 332 C.Y. 5.380 1,785.994 Gallons Total Fuel 2,254.865 Gallons Per S.F. 0.626 Gallons/S.F. Exhibit 4-3. Bridge demolition calculations. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Clearing 200.000 Gallons/Acre N/A 194.400 Gallons/Acre 191.200 Gallons/Acre .F.L/snollaG 368.0 .F.L/snollaG 057.1 A/N A/N lavomeR epiP Pavement Removal N/A N/A 0.350 Gallons/C.Y. 0.562-1.397 Gallons/C.Y. Exhibit 4-4. Clearing and removal comparison table.

92 Fuel Usage Factors in highway and Bridge Construction Analysis of the Results • 1980 Technical Advisory—The values in Technical Advisory T5080.3 range from 0.38 to 0.64 gallons per cubic yard. This range includes rock and dirt excavation activities. • Survey Results—The survey results were tabulated and adjusted based on an analysis of each response. There were some values that were removed from the sample in that the values were not within realistic ranges. In addition, there were some responses that were not calculated using the requested units of measure. For example, one respondent based their calculations on a per hour fuel consumption rate which is not able to be converted into a per cubic yard rate without additional information. • Engineering Study—The engineering study was able to develop grading estimates for 10 dif­ ferent categories of work, all related to grading activities on a project. Exhibit 4­5 lists the estimates that were developed. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. The value returned from the statistical analysis of 367 gallons per cubic yard does not relate to any factor developed by any other method and is not in the range of realistic values. Conclusion Exhibit 4­6 represents the values from the four different data sources. The task list from the contractor survey is very similar to the tasks in the engineering study. Technical Advisory T5080.3 lists values for “rock” and “dirt” excavation only with ranges from low, average, and high. The values shown in the Technical Advisory T5080.3 column in Exhibit 4­6 and Exhibit 4­7 represent the average values from the Technical Advisory T5080.3 table. The engineering study lists a separate task for rock drilling and blasting. Technical Advisory T5080.3 and the contractor survey did not list this task as a separate activity. Therefore, for the purposes of comparison, the engineering study values for rock grading tasks were adjusted upward to include the rock drilling and blasting fuel use factor of 0.053 gallons per cubic yards. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Grading–Dirt Off Road–Long 0.440 Gallons/C.Y. N/A 0.380 Gallons/C.Y. 0.320 Gallons/C.Y. Grading–Dirt Off Road–Short N/A N/A 0.310 Gallons/C.Y. 0.263 Gallons/C.Y. Grading–Dirt On Road–Long N/A N/A 0.370 Gallons/C.Y. 0.687 Gallons/C.Y. Grading–Dirt On Road–Short N/A N/A 0.310 Gallons/C.Y. 0.319 Gallons/C.Y. Grading–Rock Off Road–Long 0.570 Gallons/C.Y. N/A 0.440 Gallons/C.Y. 0.402 Gallons/C.Y. Grading–Rock Off Road–Short N/A N/A 0.350 Gallons/C.Y. 0.311 Gallons/C.Y. Grading–Rock On Road–Long N/A N/A 0.490 Gallons/C.Y. 0.740 Gallons/C.Y. Grading–Rock On Road -Short N/A N/A 0.410 Gallons/C.Y. 0.465 Gallons/C.Y. .Y.S/snollaG 370.0 .Y.S/snollaG 091.0 A/N A/N gnihsiniF yawdaoR Exhibit 4-6. Grading and excavation comparison table. Task Description Fuel Use Per Unit Units Grading - Dirt - Off Road - Long Haul 0.320 Gallons/C.Y. Grading - Dirt - Off Road - Short Haul 0.263 Gallons/C.Y. Grading - Dirt - On Road - Long Haul 0.687 Gallons/C.Y. Grading - Dirt - On Road - Short Haul 0.319 Gallons/C.Y. Grading - Rock - Off Road - Long Haul 0.349 Gallons/C.Y. Grading - Rock - Off Road - Short Haul 0.258 Gallons/C.Y. Grading - Rock - On Road - Long Haul 0.687 Gallons/C.Y. Grading - Rock - On Road - Short Haul 0.412 Gallons/C.Y. .Y.S/snollaG 370.0 gnihsiniF debdaoR Rock Drilling and Blasting (Only) (No Haul) 0.053 Gallons/C.Y. Exhibit 4-5. Grading engineering results.

Conclusions, recommendations, and Future research 93 To facilitate comparisons across estimating methodologies, Exhibits 4­7 through 4­9 provide average data for particular types of grading. Exhibit 4­7 provides data by soil type, Exhibit 4­8 provides data by length of haul, and Exhibit 4­9 provides data for on­ and off­road hauls. Exhibit 4­7 allows for the closest comparison between the three studies because Technical Advi­ sory T5080.3 includes only two categories of grading (dirt and rock). Using Exhibit 4­6 as a guide, there is substantial agreement in the overall fuel use for grading, but there is also variation concerning the impact of soil type, haul distance, and on/off road project characteristics. The percent difference between the values in Exhibit 4­7, 4­8, and 4­9 varies noticeably between the three studies. For example, the largest discrepancy is found in Exhibit 4­9, where the difference in the estimates between off­road and on­road grading varies by 71 percent in the engineering study and varies by only 8 percent in the contractor study. According to the study team’s engineering experts, the cost for grading on­road with smaller, less efficient equipment combined with longer average hauling distances for on­road grading would dictate a much higher fuel use factor for on­road grading. Therefore, the variations due to project characteristics in the contractor survey appear less reliable, and the final fuel factors incorporated the engineering estimates. 4.1.3 Base Stone This section presents the research team’s findings regarding the fuel usage associated with base stone activities. The base stone category involves the hauling, placement, and compacting of base stone for the purpose of creating a stable roadway sub­layer. Analysis of the Results • 1980 Technical Advisory—The values in Technical Advisory T5080.3 study range from 0.535 to 0.825 gallons per ton based on two haul distances, short and long. • Survey Results—There was no meaningful data for hauling and placing base stone from the contractor survey. • Engineering Study—The engineering study was based on a single average haul distance of a 10­mile haul and the results are shown in Exhibit 4­10. • Statistical Analysis—The statistical analysis calculated fuel usage of 2.56 gallons of fuel consumed per ton of base stone (short haul). Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Grading–Dirt 0.440 Gallons/C.Y. N/A 0.340 Gallons/C.Y. 0.397 Gallons/C.Y. Grading–Rock 0.570 Gallons/C.Y. N/A 0.420 Gallons/C.Y. 0.480 Gallons/C.Y. Percent Difference 30% 24% 21% Exhibit 4-7. Grading and excavation comparison table (dirt vs. rock). Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Grading–Long N/A N/A 0.410 Gallons/C.Y. 0.537 Gallons/C.Y. Grading–Short N/A N/A 0.360 Gallons/C.Y. 0.340 Gallons/C.Y. %75 %41 ecnereffiD tnecreP Exhibit 4-8. Grading and excavation comparison table (short vs. long haul). Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Grading–Off Road N/A N/A 0.370 Gallons/C.Y. 0.324 Gallons/C.Y. Grading–On Road N/A N/A 0.400 Gallons/C.Y. 0.553 Gallons/C.Y. %17 %8 ecnereffiD tnecreP Exhibit 4-9. Grading and excavation comparison table (on road vs. off road).

94 Fuel Usage Factors in highway and Bridge Construction Conclusion Exhibit 4­11 represents the values from the four different data sources. Technical Advisory T5080.3 lists values for both long and short haul, where the engineering study only lists one value for the task. Technical Advisory T5080.3 values are considerably higher, even for the short­haul option, than the results of the engineering study. As can be seen in other areas of the study (specifically the grading and asphalt sections), the haul distance can play a significant role on the amount of fuel consumed. Based on this analysis, the research team adjusted the engineering study to reflect a short­ and long­haul distance to more closely resemble Technical Advisory T5080.3. The following table represents the updated engineering study using short and long hauls. For the purposes of the engineering study, short­haul distances are defined as 10 miles from the quarry to the project site and long­haul distances are defined as 20 miles from the quarry to the project site. Exhibit 4­12 displays fuel consumption information with the revised engineering calculations. 4.1.4 Asphalt This section presents the research team’s findings regarding the fuel usage associated with asphalt activities. Asphalt activities include the laying of hot mix asphalt in leveling, structural, and surface courses. Analysis of the Results • 1980 Technical Advisory—Exhibit 4­13 lists the average fuel use factors for asphalt operations in each of three tasks: production, hauling, and placement. Placement includes place and compact. The production factor is based on using diesel fuel for the plant heating and drying operation. In Attachment 1 of Technical Advisory T5080.3 there is no adjustment listed for natural gas– operated plants. However, Attachment 2 contains a note that states, “. . . if natural gas is used for aggregate drying, deduct 2.00 Gallons/Ton.” • Survey Results—The survey results were tabulated and adjusted based on an analysis of each response. There were some values that were removed from the sample in that the values were not within realistic ranges. In addition, some of the responses were not in the requested unit of measure and they could not be converted without additional information. Task Description Fuel Use Per Unit Units Base Stone – Short Haul (Haul and Place) 0.406 Gallons/Ton Exhibit 4-10. Base stone engineering results. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Base Stone – Short Haul 0.535 Gallons/Ton 2.56 Gallons/Ton N/A 0.406 Gallons/Ton Base Stone – Long Haul 0.825 Gallons/Ton N/A N/A 0.406 Gallons/Ton Exhibit 4-11. Base stone comparison table. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Base Stone – Short Haul 0.535 Gallons/Ton 2.56 Gallons/Ton N/A 0.406 Gallons/Ton Base Stone – Long Haul 0.825 Gallons/Ton N/A N/A 0.558 Gallons/Ton Exhibit 4-12. Revised base stone comparison table.

Conclusions, recommendations, and Future research 95 • Engineering Study—The engineering study was based on three different average haul distances (0–5 miles, 5–15 miles, over 15 miles) as well as three different mix types (leveling, structural, and surface courses). Each of the values in Exhibit 4­14 includes plant production, hauling, and placing and compacting. The plant production is based on diesel fuel as the main drying fuel source. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. Conclusion Exhibit 4­15 represents the values from the four different data sources. Technical Advisory T5080.3 lists values for both long and short hauls while the engineering study only lists one value for the task. As illustrated in Exhibit 4­15, the comparisons between data sources are not based on the same breakdown of cost. In order to obtain a better basis of comparison, the engineering team restructured the engineering study to separate the production, hauling, and placement activities. During this process, it was discovered that there was a substantial difference in the estimates of plant fuel consumption rates for the drying operation. Converting the consumption rates from Technical Advisory T5080.3, the contractor survey and the engineering study based on an average plant production of 200.000 tons per hour yielded the following results: • Technical Advisory T5080.3 (2 Gallons/Ton): 400.000 Gallons/Hour, • Contractor Survey (1.98 Gallons/Ton): 396.000 Gallons/Hour, • Engineering Study: 40.000 Gallons/Hour, and • Additional Source: Astec Plant Guideline (2 Gallons/Ton): 400.000 Gallons/Hour. Based on these values, the engineering study was updated to use a plant capacity of 200.000 tons per hour and a fuel consumption rate of 400 gallons per hour. In addition, the variance between Task Description Fuel Use Per Unit Units noT/snollaG 075.2 noitcudorP noT/snollaG 015.0 )selim 01-0( gniluaH noT/snollaG 018.0 )selim 02-01( gniluaH noT/snollaG 082.0 tnemecalP Exhibit 4-13. Asphalt items within Technical Advisory T5080.3. Task Description Fuel Use Per Unit Units Hot Mix Asphalt - Leveling Course (0-5 Mile Haul) 0.892 Gallons/Ton Hot Mix Asphalt - Leveling Course (5-15 Mile Haul) 0.977 Gallons/Ton Hot Mix Asphalt - Leveling Course (Over 15 Mile Haul) 1.061 Gallons/Ton Hot Mix Asphalt - Structural Course (0-5 Mile Haul) 0.580 Gallons/Ton Hot Mix Asphalt - Structural Course (5-15 Mile Haul) 0.718 Gallons/Ton Hot Mix Asphalt - Structural Course (Over 15 Mile Haul) 0.745 Gallons/Ton Hot Mix Asphalt - Surface Course (0-5 Mile Haul) 0.770 Gallons/Ton Hot Mix Asphalt - Surface Course (5-15 Mile Haul) 0.847 Gallons/Ton Hot Mix Asphalt - Surface Course (Over 15 Mile Haul) 0.994 Gallons/Ton Exhibit 4-14. Asphalt engineering results.

96 Fuel Usage Factors in highway and Bridge Construction mix types in the contractor survey was not significant, and many respondents reported the same fuel use values for each mix type. The haul distance was a much larger factor in determining fuel consumption than place and compact activities. Therefore, the engineering study was updated to include an average for all mix types. Warm mix asphalt (WMA) represents a minor but growing segment of the asphalt paving industry. WMA is produced at temperatures that are between 30 and 120 degrees cooler than hot mix asphalt (HMA). These reduced temperatures during production result in fuel savings. Current FHWA guidance states that WMA production requires 20 percent less fuel than HMA production. Contractor survey results and selected interviews with warm mix asphalt contractors indicated that hauling and placement fuel usage does not markedly differ between hot and warm mix asphalt. The contractor survey attempted to collect WMA fuel use information independent of HMA fuel usage. However, the survey effort did not garner enough distinct fuel use information from WMA to contribute to the development of fuel factors. To account for the growing use of WMA production procedures, the study team created three WMA production fuel usage factors. The first is for diesel plants and is presented in gallons per ton, the second is for natural gas plants in BTUs per ton, and the third is natural gas support equipment. These factors were computed by applying the 20 percent plant production fuel reduction estimate developed by the FHWA to the three existing asphalt production fuel factors. The study team also converted the two natural gas asphalt production items to a gallons of gasoline equivalent (GGE) of 125,000 BTUs per gallon, a common benchmark in the estimating industry. Exhibit 4­16 presents a comparison table that contains the revised asphalt fuel usage data. 4.1.5 Milling This section presents the research team’s findings regarding the fuel usage associated with milling activities. Milling is the act of reclaiming asphalt concrete from roadways so that it may be recycled or discarded. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Asphalt Production (Diesel) 2.570 Gallons/Ton (2.000 for Plant) N/A 1.980 Gallons/Ton N/A Asphalt Production (Gas) 0.570 Gallons/Ton (Support Equipment) N/A 268,000.000 BTU/Ton plus 0.110 Gallons/Ton (Support Equipment) N/A Hauling 0-10 Miles 0.680 Gallons/Ton N/A N/A N/A Hauling 10-20 Miles 1.070 Gallons/Ton N/A N/A N/A Placement 0.280 Gallons/Ton N/A 0.580 Gallons/Ton (Average of All Mix Types) N/A Hauling 0-5 Miles N/A N/A 0.190 Gallons/Ton 0.747 Gallons/Ton (Average All Mix Types) (Includes Production and Placement) Hauling 5-15 Miles N/A N/A 0.380 Gallons/Ton 0.847 Gallons/Ton (Average All Mix Types) (Includes Production and Placement) Hauling >15 Miles N/A N/A 0.760 Gallons/Ton 0.933 Gallons/Ton (Average All Mix Types) (Includes Production and Placement) Exhibit 4-15. Asphalt comparison table.

Conclusions, recommendations, and Future research 97 Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 does not include any data for milling operations. • Survey Results—The results from the survey were consistent for each question. The detailed data for each haul distance was also consistent and logical. The results of the survey showed a significant difference from the values developed in the engineering study. • Engineering Study—The engineering study was able to break down the milling activities into two basic work activities based on milling depth, and then each of these two depths was further broken down into three different haul lengths. Exhibit 4­17 lists the results. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. Conclusion Exhibit 4­18 represents the values from the four different data sources. The contractor survey values are considerably higher than the engineering study for all thicknesses and haul distances. Based on these results, the engineering team revisited the parameters used in the engineering Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Asphalt Production (Diesel) 2.570 Gallons/Ton (2.000 for Plant) N/A 1.980 Gallons/Ton 2.040 Gallons/Ton Asphalt Production (Gas) 0.570 Gallons/Ton (Support Equipment) N/A 2.144 Gallons (GGE)/Ton 0.110 Gallons/Ton (Support Equipment) 0.090 Gallons/Ton (Support Equipment) Warm Mix Asphalt Production (Diesel) N/A N/A N/A 1.632 Gallons/Ton Warm Mix Asphalt Production (Gas) N/A N/A N/A 1.715 Gallons (GGE)/Ton 0.072 Gallons/Ton (Support Equipment) Hauling 0-5 Miles 0.680 Gallons/Ton (0-10 Mile Haul) N/A 0.190 Gallons/Ton 0.183 Gallons/Ton Hauling 6-15 Miles N/A N/A 0.380 Gallons/Ton 0.293 Gallons/Ton Hauling >15 Miles 1.070 Gallons/Ton (10-20 Mile Haul) N/A 0.760 Gallons/Ton 0.514 Gallons/Ton Placement 0.280 Gallons/Ton N/A 0.580 Gallons/Ton 0.273 Gallons/Ton Exhibit 4-16. Revised asphalt comparison table. Task Description Fuel Use Per Unit Units .Y.S/snollaG 010.0 )luaH eliM 5-0( )"1-0( gnilliM Milling (0-1") (5-15 Mile Haul) 0.011 Gallons/S.Y. Milling (0-1") (Over 15 Mile Haul) 0.014 Gallons/S.Y. .Y.S/snollaG 310.0 )luaH eliM 5-0( )"4-2( gnilliM Milling (2-4") (5-15 Mile Haul) 0.018 Gallons/S.Y. Milling (2-4") (Over 15 Mile Haul) 0.025 Gallons/S.Y. Exhibit 4-17. Milling engineering results. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study noT/snollaG 010.0 noT/snollaG 620.0 A/N A/N luah elim 5-0 ”1-0 gnilliM noT/snollaG 110.0 noT/snollaG 430.0 A/N A/N luah elim 51-6 ”1-0 gnilliM noT/snollaG 410.0 noT/snollaG 440.0 A/N A/N luah elim 51> ”1-0 gnilliM noT/snollaG 310.0 noT/snollaG 050.0 A/N A/N luah elim 5-0 ”4-2 gnilliM noT/snollaG 810.0 noT/snollaG 070.0 A/N A/N luah elim 51-6 ”4-2 gnilliM noT/snollaG 520.0 noT/snollaG 490.0 A/N A/N luah elim 51> ”4-2 gnilliM Exhibit 4-18. Milling comparison table.

98 Fuel Usage Factors in highway and Bridge Construction study. The specific areas that were re­evaluated were the hauling cycle times and the crew production rates. Based on this analysis, it was determined that the cycle times were too short based on “average” traffic conditions. On average across each of the milling tasks this added approximately one haul­ ing unit to each activity. The other area the team re­evaluated was the production rates used for the milling activity. After some recalculation, the per square yard production rate for 0–1″ thick milling was based on maximum machine milling rates as opposed to average project rates. In addition, the 2–4″ thick milling production rate was further reduced on a “per square yard” basis since the volume of material increases approximately three times based on the average thickness. The milling production adjustments are presented in Exhibit 4­19. Exhibit 4­20 has been updated to reflect these two adjustments in the engineering study. With the revised factors, the values reflected in the survey and the engineering study are more reflective of current construction practice. 4.1.6 Structures This section presents the study findings regarding the fuel usage associated with structures. Activities under this category include the various actions required to build a structure, including the laying of substructure and superstructure concrete, reinforcing steel, and steel beams. Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 lists fuel use factors for structures based on the number of gallons per contract dollar. This value ranges from 20 to 60 gallons per $1,000. • Survey Results—The survey results were very limited. The results for the concrete pavement items were somewhat consistent with half of the responses specifically excluding the hauling from the calculations. Given the limited number of responses and the large variations in the values for the other concrete items (sidewalk, curb and gutter, and retaining walls), the data were not able to be used in the analysis. • Engineering Study—The engineering team formulated fuel use estimates for each of the elements of bridge construction. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. 0-1” Thick 2-4” Thick Original Production Rate 6,250 S.Y./Hour 6,250 S.Y./Hour Revised Production Rate 2,570 S.Y./Hour 1,150 S.Y./Hour Exhibit 4-19. Revised milling production rates. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study noT/snollaG 820.0 noT/snollaG 620.0 A/N A/N luaH eliM 5-0 ”1-0 gnilliM Milling 0-1” 6-15 Mile Haul N/A N/A 0.034 Gallons/Ton 0.030 Gallons/Ton noT/snollaG 830.0 noT/snollaG 440.0 A/N A/N luaH eliM 51> ”1-0 gnilliM noT/snollaG 260.0 noT/snollaG 050.0 A/N A/N luaH eliM 5-0 ”4-2 gnilliM Milling 2-4” 6-15 Mile Haul N/A N/A 0.070 Gallons/Ton 0.071 Gallons/Ton noT/snollaG 090.0 noT/snollaG 490.0 A/N A/N luaH eliM 51> ”4-2 gnilliM Exhibit 4-20. Revised milling comparison table.

Conclusions, recommendations, and Future research 99 One of the main products of this project is the formulation of a fuel usage factor for bridge construction that is measured on a square foot basis and not on a per contract dollar basis. The project team estimated the construction steps and components, quantities, fuel used, and—finally—the gallons of fuel used per square foot of deck for a medium­sized bridge. The assumptions of the bridge size and design, as well as the actual calculation, are presented in Exhibits 4­21 and 4­22. Exhibit 4­23 presents the results of the engineering analysis. Characteristic Assumption Travel Lanes Two lanes, 12 foot width each teef 001 htgneL egdirB hcae teef 6 sredluohS )retnec ,thgir ,tfel( 3 sretooF dnal yrD napS .F.S 00,63 aerA kceD sehcni 01 ssenkcihT kceD Exhibit 4-21. Structure construction assumptions. Construction Calculation Task Element Quantity Fuel Use Per Unit Fuel Used for Task Element Substructure Piling 840 L.F. 0.433 363.720 Gallons Excavation 68 C.Y. 0.975 66.300 Gallons Form Footings 3 Each 16.000 48.000 Gallons Form Substructure 109 C.Y. 2.972 323.948 Gallons Place and Tie Rebar 44,250 Lbs. 0.004 177.000 Gallons Pour Footing 68 C.Y. 0.951 64.668 Gallons Pour Substructure 109 C.Y. 3.511 382.699 Gallons Superstructure Form Deck 115 C.Y. 2.522 290.030 Gallons Place and Tie Rebar 28,750 Lbs. 0.004 115.000 Gallons Pour Deck 115 C.Y. 1.774 204.010 Gallons Place and Tie Rebar 10,000 Lbs. 0.004 40.000 Gallons Pour Barrier Wall 40 C.Y. 3.600 144.000 Gallons Total Fuel 2,219.375 Gallons Per S.F. 0.616 Gallons/S.F. Exhibit 4-22. Structure construction calculations. Exhibit 4-23. Structures engineering results. Task Description Fuel Use Per Unit Units .B.L/snollaG 400.0 leetS gnicrofnieR .F.L/snollaG 081.0 smaeB leetS .Y.C/snollaG 007.4 etercnoC erutcurtsbuS .Y.C/snollaG 051.4 etercnoC erutcurtsrepuS $ tcartnoC/snollaG 002.5 segdirB Bridges (per S.F. of Deck)* 0.616 Gallons/S.F. *Additional task calculated following panel input

100 Fuel Usage Factors in highway and Bridge Construction Conclusion Exhibit 4­24 presents the values from the four different data sources. In order to compare Technical Advisory T5080.3 values with the other results, the research team investigated average unit prices for a select group of items that closely match the items listed in the above tables. The results of this analysis are listed in Exhibit 4­25. Based on the results of this analysis there is a very large variance in the values calculated in gallons per $1,000. It is apparent that the costs have increased substantially between 1980 and 2011. For example, if the cost has doubled over a set period of time, then a fuel factor based on dollars of contract will be reduced by 50 percent (assuming little change in construction methods requiring equipment and little change in fuel economy). Increased construction costs over the 30­year span accounts for a large amount of this change. 4.1.7 Miscellaneous Concrete This section presents the research team’s findings regarding the fuel usage associated with miscellaneous concrete activities. This category includes the installation of concrete medians, barriers, retaining walls, curbs, gutters, and sidewalks, as seen in Exhibit 4­26. Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 lists item factors only for concrete pavement. These factors are further broken down by production, hauling, and placement, as shown in Exhibit 4­27. • Survey Results—The survey results were limited. The results for the concrete pavement items were somewhat consistent with half of the responses specifically excluding the hauling from the calculations. Given the limited number of responses and the large variations in the values for the other concrete items (sidewalk, curb and gutter, and retaining walls) the data were not able to be used in the analysis. • Engineering Study—The engineering study developed factors for each of the items listed in Exhibit 4­26. The factors in the engineering study include “ready­mix” truck hauling in the calculations and concrete plant production. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Reinforcing Steel 20-60 Gallons/$1,000 N/A 0.003 Gallons/Lbs. 0.004 Gallons/Lbs. Steel Beams 20-60 Gallons/$1,000 N/A 1.390 Gallons/L.F. (2) 0.180 Gallons/L.F. Substructure Concrete 20-60 Gallons/$1,000 N/A 7.950 Gallons/C.Y. 4.700 Gallons/C.Y. Superstructure Concrete 20-60 Gallons/$1,000 N/A 5.110 Gallons/C.Y. 4.150 Gallons/C.Y. Exhibit 4-24. Structures comparison table. Task Technical Advisory T5080.3 Engineering Study Reinforcing Steel 20-60 Gallons/$1,000 5.200 Gallons/$1000 Exhibit 4-25. Structures comparison table per contract dollar.

Conclusions, recommendations, and Future research 101 Conclusion Exhibit 4­27 represents the values from the four different data sources. Based on these estimates, the engineering team separated the hauling of the concrete from the placement activities in order to facilitate comparisons. The original study was based on a single average haul distance of 10 miles. To be consistent with other areas within the engineering study, the team established a short­ and a long­haul activity using 10 miles for the short haul and 20 miles for the long haul. Exhibit 4­28 presents a comparison table that reflects the revised hauling calculations. As can be seen in the adjusted engineering calculations, the factors between the three studies are consistent. Two observations in the study need to be highlighted. First, there is an observable variance between the Technical Advisory T5080.3 factor for placement (0.450 Gallons/C.Y.) and the other two results in the survey and engineering study (0.300 and 0.267 Gallons/C.Y.). The second area relates to the value for the concrete production. The survey and the engineering study did not address this activity. This is because production of concrete is generally undertaken by a third party, not by the contractor placing the concrete. Task Description Fuel Use Per Unit Units Concrete Pavement (</= 6 Thick) 0.650 Gallons/S.Y. Concrete Pavement (>6 Thick) 0.867 Gallons/S.Y. .F.L/snollaG 531.0 rettuG dna bruC .F.S/snollaG 927.0 llaW gniniateR .F.L/snollaG 063.0 klawediS .F.L/snollaG 251.0 #*rettuG/bruC etercnoC .F.S/snollaG 090.0 #*klawediS etercnoC Retaining Wall (Cast-in-Place)*# 0.646 Gallons/S.F. .F.S/snollaG 403.0 *)tsaC-erP( llaW esioN Concrete Median Barrier*# 0.309 Gallons/L.F. * Additional tasks calculated following panel input. # Includes concrete production and hauling. Exhibit 4-26. Miscellaneous concrete engineering results. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Concrete A/N A/N A/N .Y.C/snollaG 34.0 noitcudorP Concrete Hauling 1.00 Gallons/C.Y. N/A 0.050 Gallons/C.Y./Mile A/N )esnopseR 1( Placement 0.45 Gallons/C.Y. N/A 0.300 Gallons/C.Y. 0.759 Gallons/C.Y. Average Including Haul Exhibit 4-27. Miscellaneous concrete comparison table. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Concrete Production 0.430 Gallons/C.Y. N/A N/A N/A Concrete Hauling – Short Haul 1.000 Gallons/C.Y. N/A 0.050 Gallons/C.Y./Mile (1 Response) 0.600 Gallons/C.Y. Concrete Hauling – Long Haul 1.000 Gallons/C.Y. 0.050 Gallons/C.Y./Mile 1.100 Gallons/C.Y. Placement 0.450 Gallons/C.Y. N/A 0.300 Gallons/C.Y. 0.267 Gallons/C.Y. Exhibit 4-28. Revised hauling comparison table.

102 Fuel Usage Factors in highway and Bridge Construction 4.1.8 Drainage Pipe and Structures This section presents the research team’s findings regarding the fuel usage associated with drainage pipe and structure activities. This category includes the installation of concrete water and sewage pipes. Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 does not include any data for laying any type of pipe (storm drain, water, or sewer). • Survey Results—The survey results were limited and varied substantially between water and sewer items to the point where the results were not meaningful. • Engineering Study—The engineering study was able to break down the drainage tasks into multiple categories of work all related to storm sewer, water line, and sanitary sewer activities on a project. Exhibit 4­29 lists the results. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. Conclusion Exhibit 4­30 represents the values from the four different data sources where there was data available to compare. As mentioned in the contractor survey section, the limited and variable data for the water and sanitary sewer activities were not able to be used in a comparison. The values in all the tasks are somewhat variable with the storm pipe structures item variance significantly higher than that for the other tasks. This is due to the unit of measures being different between the two studies. The survey results are based on a per structure basis, whereas the engineering study is based on a per cubic yard of concrete included in each structure. In order to compare these values, the engineering team developed an estimate of the number of cubic yards per structure for “average” conditions of 3.000 cubic yards per structure. Based on this factor, the storm pipe comparison is shown in Exhibit 4­31. Task Description Fuel Use Per Unit Units 527.8 serutcurtS eganiarD Gallons/C.Y. .F.L/snollaG 833.4 )epiP "63 >( werC epiP egraL Medium Pipe Crew (>18" to 36" Pipe) 1.481 Gallons/L.F. .F.L/snollaG 090.2 )htpeD '4 revO( eniL reweS .F.L/snollaG 540.1 )htpeD '4 ot pU( eniL reweS Small Pipe Crew (</= 18" Pipe) 0.871 Gallons/L.F. .F.L/snollaG 090.2 )htpeD '4 revO( eniL retaW .F.L/snollaG 540.1 )htpeD '4 ot pU( eniL retaW hcaE/snollaG 000.5 selohnaM reweS/retaW Exhibit 4-29. Drainage pipe and structures engineer- ing results. Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Large Pipe Crew N/A N/A 3.308 Gallons/Ton 4.338 Gallons/L.F. Medium Pipe Crew N/A N/A 2.332 Gallons/Ton 1.481 Gallons/L.F. Small Pipe Crew N/A N/A 1.600 Gallons/Ton 0.871 Gallons/L.F. Storm Pipe Structures N/A N/A 40.715 Gallons/Each 8.725 Gallons/C.Y. Exhibit 4-30. Drainage pipe and structures comparison table.

Conclusions, recommendations, and Future research 103 4.1.9 Specialty Items This section presents the research team’s findings regarding the fuel usage associated with specialty items. This category includes other items that are not categorized in the above areas, including signalization, fencing, striping, and other activities. Analysis of the Results • 1980 Technical Advisory—Technical Advisory T5080.3 lists none of the activities included in this section. • Survey Results—No meaningful values were able to be extracted from the contractor survey. • Engineering Study—The engineering study developed factors for each of the items listed in Exhibit 4­32. • Statistical Analysis—No meaningful values were able to be extracted from the statistical analysis. 4.1.10 Conclusion For this effort, the research team compared data across the three study methodologies and the original fuel factors as presented in Technical Advisory T5080.3. Where the research had enough data to make a valid comparison, there was substantial agreement between the sources regarding activity fuel use. In particular, the survey data validated the engineering estimates. Where there was disagreement among the data sources, the engineering estimates were reassessed and generally revised to reflect the figures garnered from the survey effort. 4.2 Other Potential Applications of Fuel Use Data The purpose of this section is to explore other potential applications of the fuel usage data developed in this study. The primary intended audience or “market” for the products of this study will be the state DOTs and, in particular, the contracting authorities that request bids for Task Technical Advisory T5080.3 Statistical Analysis Contractor Survey Engineering Study Storm Pipe Structures N/A N/A 40.715 Gallons/Each 26.175 Gallons/Each Exhibit 4-31. Revised drainage pipe and structures comparison table. Task Description Fuel Use Per Unit Units hcaE/snollaG 052.4 setaG ecneF .F.L/snollaG 340.0 )thgieH '6 revO( gnicneF .F.L/snollaG 340.0 )thgieH '6 ot pU( gnicneF ercA/snollaG 794.3 )gnideeS ordyH( gnissarG hcaE/snollaG 240.0 stsoP liardrauG Intersection Signalization (2 Lane) 170.000 Gallons/Each Intersection Signalization (4 Lane) 340.000 Gallons/Each ercA/snollaG 000.01 noitaraperP debdeeS .M.L/snollaG 005.4 gnikraM tnemevaP pikS .M.L/snollaG 005.4 gnikraM tnemevaP diloS .Y.S/snollaG 710.0 doS .F.L/snollaG 730.0 liardrauG leetS .Y.C/snollaG 761.0 liospoT pirtS .F.L/snollaG 501.0 liardrauG elbaC/eriW Exhibit 4-32. Specialty items engineering results.

104 Fuel Usage Factors in highway and Bridge Construction highway construction or maintenance. However, this guidance will also be useful for a variety of other entities and uses. The research team undertook a variety of activities in order to explore these other potential activities. First, the team queried selected state DOT representatives to ascertain whether they envisioned additional uses for the fuel factor data. Second, the team reached out to the NCHRP project panel for their input and assistance. In both instances, the inquiries polled respondents on their impressions as to the usefulness of the data to potential users. Finally, the team reviewed pertinent literature collected throughout the study for information on potential additional audiences. The research revealed six major additional markets for the results of this study. These include the following: • Other agencies responsible for highway contracting; • Agencies responsible for construction of facilities for other transportation modes; • Associations representing industries that build highways or provide goods to highway builders; • Officials interested in improving planning and budgeting; • Contractors interested in better understanding and managing their fuel use or in preparing more accurate cost estimates; and • Researchers examining energy requirements, emissions, and climate change. The following sections describe each of these markets. Included in each section is a descrip­ tion of the market, an overview of the potential application of the fuel factors data within that market, and a summary of respondent’s impressions as to the usefulness of the data to potential users in that market. 4.2.1 Other Agencies Responsible for Highway Contracting The most evident alternative application of fuel factors is their use by contracting authorities at other governmental levels (federal, county, MPO, city, town, local) that purchase highway construction. Based on the knowledge of the expert engineering panel, at present, the use of fuel factors at these jurisdictions is extremely rare because these entities employ a much lower level of budgeting and project estimating. State DOTs, however, do not maintain ownership over the majority of roads. For example, Exhibit 4­33 provides data for 2008 on the ownership of road mileage by jurisdiction. State highway agencies own only 19.3 percent of roads, while counties own 44.0 percent, and towns and municipalities own 32.0 percent. These totals include 1,324,245 miles of unpaved roads, Highway Statistics 2008, Table HM-16, “Public Road Length – 2008 Miles by Ownership and Federal-Aid Highways National Summary,” October 2009, Federal Highway Administration, accessed at URL: http://www.fhwa.dot.gov/policyinformation/statistics/2008/hm16.cfm Ownership Miles Percent of Miles State Highway Agency 784,312 3.91 County 1,788,039 0.44 Town, Township, Municipal 1,298,413 0.23 Other Jurisdictions 57,021 4.1 Federal Agency 131,558 2.3 343,950,4latoT 0.001 Exhibit 4-33. Ownership of road mileage by jurisdiction, 2008.

Conclusions, recommendations, and Future research 105 which account for 32.6 percent of all roads. Although ownership data for paved roads is only available for select functional classes, available data are sufficient to establish that state highway agencies own no more than 28.5 percent of paved roads. The upper range estimate assumes that state highway agencies own all minor collectors (179,622 miles). Also included is mileage for functional classes for which paved mileage is available for state highway agencies including rural roads (472,237 miles) and urban roads (128,155 miles). The sum represents 28.5 percent off all paved roads (2,734,102 miles). The ownership situation is similar for bridges. As shown in Exhibit 4­34, state highway agencies own only 46.6 percent of bridges while counties own 37.9 percent, towns own 4.9 percent, and cities and municipalities own 7.1 percent. Given the large percentage of roads that non­state jurisdictions build, own, and maintain, these other jurisdictions represent a large potential user of fuel factors and price adjustment clauses. 4.2.2 Agencies Responsible for Other Modes In addition to public roads, a number of public and private entities build and maintain roads, other paved surfaces similar to roads, and other graded rights­of­way that require preparation similar to a highway right­of­way. Some of these facility types include • Airports, • Parking facilities, • Transit facilities, • Private roads at commercial and industrial facilities, • Private roads at residential communities or subdivisions, • Railroads, and • Ports. Airports, both public and private, maintain entrance roads, service roads, parking lots, and runways. Grading and paving activities, for which fuel factors were developed, would carry over Highway Statistics 2010, Table BR-6, “Highway Bridge by Owner – Counts as of December 2010,” October 2009, Federal Highway Administration, accessed at URL: http://www.fhwa.dot.gov/bridge/nbi/ownercount10.cfm Ownership Bridges Percent of Bridges 527,182ycnegA yawhgiH etatS 6.64 County Highway Agency 229,047 9.73 Town or Township Highway Agency 29,560 9.4 City or Municipal Highway Agency 42,811 1.7 2.0 State Park, Forest, or Reservation Agency 78 1,040 Local Park, Forest, or Reservation Agency 0.0 409seicnegA etatS rehtO 1.0 292,1seicnegA lacoL rehtO 2.0 015d)aorliar naht rehto( etavirP 1.0 658daorliaR 1.0 674,7ytirohtuA lloT etatS 2.1 347ytirohtuA lloT lacoL 1.0 051,8laredeF 3.1 103nwonknU 0.0 394,406latoT 0.001 Exhibit 4-34. Ownership of bridges by jurisdiction, 2008.

106 Fuel Usage Factors in highway and Bridge Construction to airport construction and expansion. Parking facilities include roadways, parking surfaces (which are akin to road surfaces), and parking ramps (which are structures with some similarities to bridges). Transit facilities include roadways and rail rights­of­way, which require clearing, grading, landscaping, drainage, and base stone activities that are similar to roadways. Many commercial and industrial facilities include roadways. Similarly, many residential communities, subdivisions, and multifamily developments include private roads. Additionally, freight bureaus within DOTs and MPOs work with local agencies and rail­ road companies and often are involved with rail­highway grade crossing improvements and reconstruction, which is another area where fuel factors could apply. In addition, railroads use construction materials in their bituminous underlayment of tracks and other facilities. Such activities might apply to port facility construction as well. Additionally, there is a possibility that the fuel factors formulated for several heavy construc­ tion activities, such as clearing and grubbing or grading, could be used as surrogates for activities in open­pit mining, farming, environmental clean­up, or heavy industrial operations. Each of the entities procuring these roadways or roadway type elements may have interest in adopting fuel­price adjustment clauses for their contracts. The fuel factors developed in this study or the methodology used to develop the fuel factors may be useful in developing project­specific fuel quantities that will be subject to the adjustment factor. 4.2.3 Associations Representing Relevant Industries Association officials involved with industries that build highways or provide goods to highway builders may be interested in fuel factors for various reasons. One use would be to educate their members as to the benefits of conservation efforts. Another would be to help their members understand how price fluctuations can affect both their bottom line and their competitiveness. Associations can also provide the data in guidance and tools that allow their members to develop estimates for bidding purposes that are more accurate. 4.2.4 Officials Interested in Improving Planning and Budgeting State DOTs can also use the updated fuel factors in the development of more accurate state engineer’s estimates for planning and budgeting purposes. For example, the NCHRP noted that the fuel factors might be useful to planning groups or planning studies in developing comparative data for impacts of alternative development scenarios. In particular, rapid changes in fuel prices can complicate highway construction planning and budgeting. DOTs may find that bids come in higher or lower than expected or that price adjustment clauses cause unexpected changes in project costs. For example, fuel and asphalt prices during fall 2009 allowed ARRA funds to cover more projects than expected. “States are routinely receiving low bids for highway and airport construction projects that are 10 to 20 percent, and in some cases, 30 percent lower than expected.” Understanding the amounts of fuel that projects will consume can allow DOTs to better understand and plan for price fluctuations. However, according to one state DOT official, fuel price information is useful for formulating price adjustments based on what actually happens. The intent of all the price adjustments is to minimize that portion of cost risk in the longer duration public contracts. In this official’s opinion, trying to use historical data for future planning and estimating is a futile attempt, as “past performance should be taken as no indication of future performance.”

Conclusions, recommendations, and Future research 107 4.2.5 Contractors Contractors can use fuel factor data to better understand and manage their fuel use and to prepare more accurate cost estimates. Although most contractors have systems and other methods to estimate their fuel use, the availability of updated fuel factors can provide them with a benchmark to assess their estimates as well as their level of fuel efficiency. One state DOT official, however, had a contrasting view of contractor need for fuel factors. Based on this official’s experience with the contracting industry, it was this state DOT official’s belief that “Contractors already have a thorough understanding of fuel futures. The only thing that may be useful is the maximum expected growth of a factor.” 4.2.6 Researchers and Modelers Researchers and modelers may use fuel factors or the engineering data on equipment and fuel consumption rates in research studies. Topics might include climate change, particulate emis­ sions, or the energy requirements of alternative construction techniques. For example, fuel factor data might be useful in the development of air pollution models in non­attainment areas. The fuel factors and related estimates could be especially beneficial for transportation planning purposes. Although many MPOs and some DOTs have begun to estimate energy and operational greenhouse gas (GHG) emissions from the transportation systems they oversee, few have gone beyond that level of effort to evaluate construction and maintenance emissions. These emissions can be a significant contribution to the overall carbon footprint of the transportation system. In addition, many state climate action plans (and in the future, perhaps, MPO/state DOT GHG reduction plans) include infrastructure strategies such as HOV/HOT lanes, bus and rail transit, congestion reduction in general purpose lanes, and bicycle and pedestrian projects. Without a good understanding of the construction and maintenance impacts of these types of projects, planners cannot know whether these projects truly reduce energy and emissions on a life­cycle basis, or whether they provide meaningful reductions by the target years in the climate action plan or other GHG planning document. There are many examples of these types of research. For example, the authors of this report are currently part of a team developing a tool for the FHWA designed to quantify emissions from the construction and maintenance of transportation infrastructure projects (e.g., road­ ways and transit projects). That study uses the results of this study in its application. Specifi­ cally, the fuel factors developed in this study are combined with quantities to directly estimate GHG emissions. In order to produce a comprehensive analysis of the GHG impacts of proposed regional or statewide transportation plan alternatives, planners must consider the emissions associated with construction and maintenance. The information gathered in this project will be useful for both planners interested in quantifying these emissions, and state and local DOTs interested in reducing these emissions. This will also include information and data regarding the costs associated with the practices to reduce GHG emissions. These will provide practitioners with the basis for cost­benefit or cost­effectiveness analyses. In a recently published research synthesis, S. T. Muench provided an overview of roadway construction sustainability (Muench 2010). Muench’s review of 14 roadway construction life­cycle papers reveals some consistent observations about the ecological impacts of such projects. Key observations are • The energy expended during roadway construction is roughly equivalent to that used by traffic operating on the facility for 1 or 2 years, • Materials production makes up 60 to 80 percent of energy use and 60 to 90 percent of CO2 emissions associated with construction,

108 Fuel Usage Factors in highway and Bridge Construction • Construction activities at the jobsite make up less than 5 percent of energy use and CO2 emissions, and • Transportation associated with construction makes up 10 to 30 percent of energy use and about 10 percent of CO2 emissions associated with construction. The fuel factors data developed for this study could provide additional data observations for use in similar studies. The GreenDOT model, developed by AASHTO, provides a framework for estimating emissions from construction equipment. GreenDOT is a spreadsheet tool that enables state DOTs to calculate CO2 emissions from their operations and projects. Depending on the user’s need, the model can calculate CO2 emissions from an agency or a project over a defined time period (ICR International 2010). Updated fuel use inputs produced for this study could be incorporated into the GreenDOT model. Another source specifically focused on life­cycle emissions from different types of pave­ ment is a recent paper by three researchers, Hanson, Noland, and Cavale, at Rutgers Univer­ sity’s Voorhees Transportation Center. This paper, “Life Cycle Greenhouse Gas Emissions Used in Road Construction,” aggregates research on life­cycle emissions for asphalt and for Portland cement. The newly calculated fuel usage factors for relevant asphalt and concrete items could be included in an updated version of this report, or a similar report compiled in the future. The most comprehensive regional­scale analysis of greenhouse gas emissions embodied in transportation infrastructure, incorporating estimates of material volumes, is contained in the 2008 doctoral dissertation of Mikhail Chester. Chester uses emission factors from the PaLATE model to estimate emissions embodied in the construction of regional road net­ works and rail transit networks. Chester estimates volumes of construction materials sepa­ rately for 10 roadway types: interstate, major arterials, minor arterials, collectors, and local roadways in both the urban and rural context. The author developed standard dimensions for each roadway type from AASHTO’s 2001 guidance on roadway geometry and historical miles of each roadway type constructed in the United States from the Bureau of Transporta­ tion Statistics. Finally, the author estimated market shares of various paving types from EPA’s Emission Inventory Improvement Program. Chester effectively forecasts the total emissions embodied in construction of roadway pavement in the United States over a 10­year period. The fuel usage factors developed for this effort may be used as inputs to similar emission calculation models. State DOTs, in their GHG inventory development, do not appear to have maintained data for specific construction or maintenance activities. The new fuel factors data produced for this study could be incorporated into these models, with some regional and/or geographical tailoring occurring. The Washington State DOT (WSDOT), in its 2007 GHG inventory, fol­ lowed a more traditional GHG reporting protocol, thinking primarily of their fleet and their buildings as their major categories of Scope 1 and Scope 2 emissions (WSDOT 2007). The inventory does not describe estimates of emissions by project category or by activity. The inventory does not contemplate life­cycle emissions from materials as part of the inventory. This may change, as AASHTO’s Standing Committee on the Environment has recently com­ missioned a guide for state DOTs entitled “Greenhouse Gas Emission Inventory Methodolo­ gies for State Transportation Departments.” This document, prepared by ICF and finalized in the summer of 2011, contains simple estimates of upstream emissions for purchased inputs to construction projects, such as gas, diesel, and natural gas fuels as well asphalt, steel, and aluminum.

Conclusions, recommendations, and Future research 109 4.2.7 Summary and Conclusions A range of potential uses exists for the fuel usage factors data collected in this study. The data can be used by entities other than state DOTs for both highway contracting and construction of facilities for other transportation modes. Associations may value the data for dissemination of information and policy guidance for their members. Officials interested in improving planning and budgeting may find information on fuel use in their projects extremely useful. At the same time, contractors interested in better understanding and managing their fuel use or in preparing more accurate cost estimates will find value in the fuel factors. Finally, researchers examining energy requirements, emissions, and climate change can use the data in preparing estimates, inventories, and action plans.