# Category HIGHWAY ENGINEERING HANDBOOK

## EXAMPLES OF SUCCESSFUL VE HIGHWAY STUDIES

To recognize outstanding VE achievements and promote awareness of the importance of this program, the AASHTO Value Engineering Task Force has established national awards to be given to state transportation agencies. These awards are presented every 2 years to agencies that have shown special achievement in either cost-effectiveness or innovation.

TABLE 10.4 Life Cycle Cost Calculations for Two Pipes

A. Annualized cost method

 Type of cost Equation for factor Pipe A Pipe B Factor Annualized cost, \$ Factor Annualized cost, \$ Initial PP 0.0548 \$150,000 0.0548 \$180,000 = r/[1 — (1 + r)—n] X 0.0548 X 0.0548 n = 50 = \$8216 n = 50 = \$9864 Recurring — — \$1000 — 1000 Non-recurring PW 0.1420 \$37,400 0.1113 \$25,000 (rehab.) = (1 + r)— n X 0.142 X 0.0548 X 0.1113 X 0.0548 n = 40 = 291 n = 45 = \$152 Non-recurring PW 0.0872 \$30,000 (salvage)* = (1 + r)— n — — X 0.0872 X 0.0548 n = 50 = \$143 Total — — \$8507 — \$9873

Pipe A has the lower annualized cost.

Annual difference = \$9873 — 8507 = \$1366.

Present worth of annual difference = (1/0.0548) X \$1366 = \$24,900.

*Note that salvage values are treated as negative numbers in the summations for annualized cost and pre­sent worth.

B. Direct present worth method

 Pipe A Pipe B Type Equation Present Present of cost for factor Factor worth, \$ Factor worth, \$ Initial — — \$150,000 — \$180,000 Non-recurring PW 0.1420 \$37,400 X 0.142 0.1113 \$25,000 X 0.1113 (rehab.) = (1 + r— n n = 40 = \$5311 n = 45 = \$2782 Non-recurring PW 0.0872 \$30,000 (salvage)* = (1 + r)- n — — n = 50 X 0.0872 = \$2616 Total — — \$155,311 — \$180,166

Pipe A has the lower cost based on present worth.

Difference in present worth = \$180,166 — 155,311 = \$24,900 (same result as in part A).

*Note that salvage values are treated as negative numbers in the summations for annualized cost and pre­sent worth.

The VE Task Force presents the awards in the categories of (1) process improve­ment, (2) project delivery, and (3) preconstruction engineering (design, utilities, right – of-way, and construction). The awards for 2007 for the most value added proposals are summarized below.

Category: Improved Process

Agency: California Department of Transportation (Caltrans)

Project: Antioch and Dumbarton bridges Geotechnical Investigation Requirements to

Develop Retrofit Strategy

Citation:

This unique study analyzed the geotechnical investigation requirements necessary to develop the strategy that leads to retrofit recommendations for the Antioch and Dumbarton bridges. Caltrans will use this study to develop an appropriate retrofit strategy for each bridge. The baseline scope placed heavy emphasis on conducting new explorations and associated labora­tory testing to obtain more dependable data (baseline estimate of \$12,100,000). The value analysis (VA) team concluded that the objectives of the investigation could be achieved with fewer new exploratory borings drilled to somewhat shallower depths. Other recommended alternatives also improved the project and lowered cost, with implemented savings of \$2,350,000 or 19 percent. All recommended alternatives were accepted and implemented.

Category: Project Delivery

Agency: Minnesota Department of Transportation

Project: TH 212 Design-Build Project, State Project No. SP 1017 12

Citation:

The TH 212 Design-Build Project is a \$238 million construction project consisting of 11.75 miles of new four-lane divided highway realignment, 7 interchanges, 28 bridges, and numerous retaining and noise walls. The VE proposal is to eliminate a bridge and provide for the realignment of a crossing road to intersect where the main line creek crossing occurs. This combined crossing concentrates impacts and construction activities in one location. This change minimizes environmental impacts to the creek, the big woods remnant vegetation, and the flood plains, and reduces slope stability issues. The VE impacts include savings in project costs, and reduced construction impacts and future maintenance activities. The new design eliminates an insufficient horizontal curve design exception, improves sight distance at an intersection, reduces the total acreage disturbed, and creates less impervious area.

Category: Preconstruction Engineering < \$25 Million

Agency: Florida Department of Transportation Project: Protection of US 98 on Okaloosa Island Citation:

US 98 on Okaloosa Island has been damaged by storm surges from at least five tropical events in the last ten years, resulting in more than \$16 million in repair work. The purpose of this project was to provide additional protective features to reduce the potential for future damage from similar storm events. The District wanted the additional protection in place prior to the next storm season, which required the project to be designed and constructed in less than one year. The recommendation developed by the team and accepted by management reduced the cost of the \$20.6 million project by \$8.3 million, or 40 percent, and also reduced the construction time by 50 percent. A key product innovation from the VE team was the rec­ommendation to use Teflon sheet piling to replace conventional concrete sheet piling.

Category: Preconstruction Engineering \$25-\$75 Million

Agency: Transport Canada, Ontario Ministry of Transportation, and the City of Windsor Project: Let’s Get Windsor Essex Moving, Walker Road and Howard Avenue Grade Separations VE and Risk Study Citation:

Security measures at the U. S. border have caused significant traffic problems in the City of Windsor. One of the problems was the need to x-ray rail cars entering the United States, which reduced train speed and increased traffic delays at major arterial road-rail crossings in the city. An immediate and concerted effort was put into place to grade separate two major urban road crossings. The original project cost estimates increased dramatically due to the rushed design, limited property, business and industrial activities, traffic operations, and a myriad of major utility issues. A VE study and Cost Risk analysis improved commu­nication with the city, Transport Canada, Ontario Ministry of Transportation, and designers; saved \$2 million; identified risks; brought certainty to the cost estimates; and clarified project scope.

Category: Preconstruction Engineering >\$75 Million

Agency: New Jersey Department of Transportation Project: Route 52 Causeway Replacement Contract A Citation:

The Route 52 Causeway Replacement Contract A project involves the replacement of 1.2 miles of existing Route 52 Causeway, including 2 structures displaying structural, geometric, and safety deficiencies. Bids far exceeded original estimates. The VE repack­aging of Contract A converted Rainbow Island from bridge structure to roadway by grade touchdown utilizing fill. Additionally, the VE changes introduced conventional fixed bridges as an alternate design to high-level bascule bridges. VE design and bridge changes reflected through this repackaging effort resulted in a low bid of \$141,350,400, with a net savings of \$88,636,000, and improved constructibility by acquiring environ­mental permits that allowed timely construction without seasonal delays.

Category: Preconstruction Engineering >\$75 Million—Honorable Mention

Agency: Central Puget Sound Regional Transit Authority (Sound Transit)

Project: 755 Segment of Sound Transit Central Link Light Rail Project Citation:

The 755 Segment of Sound Transit Central Link Light Rail Project extends approximately 5 miles, from the Boeing Access Road to a station at Southcenter Boulevard. This LRT guideway is mostly elevated and parallels or crosses over Washington State Department of Transportation (WSDOT) freeways along much of its route. The design team undertook an intensive value engineering study of the 30 percent preliminary design at the beginning of the final design assignment. The VE study identified significant configuration changes that were forecast to save \$23 million and approximately 8 months of construction duration. Sound Transit evaluated and accepted the recommendations for incorporation into the final design. The potential savings and other benefits identified in the value engineering work were validated by the bids received and continue to be realized during construction of the \$234 million project.

[1] The alignment should be as directional as possible while still consistent with topo­graphy and the preservation of developed properties and community values.

• Maximum allowable curvature should be avoided whenever possible.

• Consistent alignment should be sought.

• Curves should be long enough to avoid the appearance of a kink.

[2] Rounding should be 4 ft where the foreslope begins beyond the clear zone or where guardrail is installed and foreslope is steeper than 6:1. No rounding is required when the foreslope is 6:1 or flatter.

Note: No attempt has been made to include every bridge type in the above tabulation.

Prestressed box beam

[5]From R. L. Brockenbrough and F. S. Merritt (eds.), Structural Steel Designer’s Handbook, 4th ed., McGraw-Hill, New York, 2006. Used with permission.

[6]Z. P. Kirpich, “Time of Concentration in Small Agricultural Watersheds,” Civil Engineering, vol. 10, p. 362, 1940.

[7]The modified Williams equation is found in Maidment, cited below. The original Williams reference is G. B. Williams, “Flood Discharge and the Dimensions of Spillways in India,” The Engineer, vol. 121, pp. 321-322, September 1922.

[8] Entrance and exit. The deceleration and acceleration lanes adjacent to the main roadway can be lighted so that a motorist can safely transition into and out of the rest area. When the main roadway is not lighted, an average illumination of 0.6 fc (6 lx) should be maintained on the deceleration with three to five luminaires along the speed change lanes. On the exit gore and acceleration lane, 0.6 fc (6 lx) is rec­ommended to a point where the motorist can merge onto the main roadway. If the main route is lighted, the entrance and exit lanes should be lighted to a level equal to that of the main route.

• Interior roadways. These are the roads for the entrance gore to the parking areas and from the parking areas to the exit gore. The recommended illumination is 0.6 fc (6 lx) with a uniformity of 3:1 to 4:1.

The design of lighting for rest areas requires consideration of both vehicle and pedes­trian needs. Properly designed rest area lighting will enhance the architectural and landscape features of the facility, promote safety by easing the task of policing, and contribute to the rest and relaxation of motorists by adequately lighting the driving, parking, and walking areas. In areas with landscaping or in natural settings, the lighting designer often attempts to make the light poles less noticeable by causing them to blend with the environment. One cost-effective method uses colored fiberglass rein­forced poles that blend with the surrounding environment. These poles are usually of the direct burial type that can be installed with or without breakaway devices.

The lighting system designer should be mindful of motorists on the travelway by not allowing glare or spill light from the rest area luminaires to adversely affect their vision. The motorist on the main roadway should be able to see any vehicles leaving the rest area as well as traffic along the main route. The lighting concerns for rest areas can be divided into several distinct areas:

[10] Obtain soil parameters for both backfill and foundation. Usually the cohesion­less backfill is slightly larger than Rankine zone. This enables the designer to use the properties of backfill material to estimate earth loads; otherwise the properties of retained material must be used.

[11] Determine the appropriate design cases and load combinations. Load types are designated as follows: D, dead load; E, earth load; SC, surcharge; RI, rail impact; and W, wind load. Typical load combinations are as follows: sloped or leveled fill without rail, D + E; leveled fill without rail, D + E + SC; leveled fill with rail, D + E + RI; and leveled fill with rail and fence, D + E + SC + W.

[12] Determine the overall design height including footing thickness T and stem height H, and select a trial footing width dimension B. (See Fig. 8.20.) Usually the toe

Table 9.2 outlines the major steps required in the development of final construction plans for a noise abatement project on an existing highway. Considerations in several of these steps are as follows.

TABLE 9.2 Project Development Steps for Noise Barriers for Existing Highways

[14] Preliminary engineering

a. Identify project limits

b. Collect data

c. Identify alternatives

[15] Public and municipal involvement

a. Discuss alternatives

b. Decide on system

[16] Preparation of preliminary plans

[17] Preliminary approvals

a. Municipal

b. State DOT

c. FHWA

[18] Final design

[19] Final approval and processing

[20] Contract letting

[21] Materials

a. Concrete Posts. Concrete posts shall be constructed as detailed in the plan and the required specification on pigmented sealer.

b. Wood Noise Walls. The facing lumber and battens shall be any species of south­ern pine conforming to the applicable provisions of DOT, modified to the extent that the lumber shall contain no holes and have tight knots. No intermixing of lumber species will be permitted within any continuous section of wall. If the wall abuts any earth fill greater than 2 ft (600 mm), the facing planks installed below the top of the fill shall be 8- X 3-in (200- X 75-mm) or 6- X 3-in (150- X 75-mm) lumber with the 3-in (75-mm) dimension being rough-sawn. All facing lumber and battens shall be pressure preservative-treated with an approved waterborne preservative as provided hereinafter. Lumber treated with Millbrite will not be acceptable.

Facing boards shall be surfaced on two sides, and shall be tongue-and-grooved. All plank facing lumber shall be no. 1 structural grade or better. Facing lumber and battens shall be stamped with the appropriate grade mark.

c. Hardware. All hardware for noise wall shall be galvanized and meet the requirements of the American National Standards Institute (ANSI) and ASTM as to strength and testing.

[22]The portions of Art. 10.2 taken from this source are used with the permission of AASHTO.

## METHODS OF CALCULATION

The concepts of annualized cost and present worth are employed in LCC. Using the annual­ized cost method, all costs incurred are converted to equivalent annual costs using a base­line and a specified life span. For example, initial costs would be amortized over the life cycle and include principal and interest (similar to home mortgage payments). Replacement costs or rehabilitation costs at various points during the life cycle would also be converted to equivalent annual costs (sinking fund). The following steps can be employed:

1. Annualized initial cost. Tabulate all initial (acquisition) costs. These include the base cost of each of the alternative systems and any other initial cost. Total these ini­tial expenditures to arrive at the total initial cost (IC). Next, amortize the initial costs (IC) by determining the annual payment necessary to pay off a loan equaling the total initial cost. Using a capital recovery table or the following equation, find the periodic payment (PP) necessary to pay off \$1.00 at a discount rate of r over a period of n years. Each total initial cost is multiplied by this factor to determine the annualized cost for this element.

r

1 – (1 + r)-n

2. Annual recurring cost. The next step is to tabulate, for each alternative, the average annually recurring costs for operations, maintenance, and other known factors.

3. Annualized nonrecurring cost. Next, determine the replacement or rehabilitation costs for all major items, for each alternative, at appropriate times during the life span. Also determine the salvage value at the end of the life span. Each of the replacement costs is then discounted from the point in time where the funds are to be expended. Multiply each cost by the present worth factor (PW) from a table or calculated by the equation

PW = (1 + r)-n

Then, the present worth of these replacement and salvage costs is reduced to a uniform series of payments by applying the same capital recovery periodic payment factor (PP) used in step 1. Salvage or residual values are treated similarly except that the resulting costs are negative.

4. Total annual cost. Finally, sum the annualized initial cost, annual recurring cost, and annualized nonrecurring cost for each alternative to determine total annual costs. These costs represent a uniform baseline of comparison for the alternatives over a projected life span at a selected interest rate. The annual differences are then deter­mined and used for recommendations.

5. Present worth of annual difference. To determine the real value of an annual cost difference, calculate its present worth. Multiply each cost by the present worth annu­ity factor (PWA), which shows how much \$1.00 paid out periodically is worth today in real dollars. The factor may be obtained from a table or calculated by the equation

1 – (1 + r)-n

r

Thus, one may then compare the present worth of each alternative to assess the bene fit derived.

6. Effect of inflation. The effect of inflation should be considered in the calculations when determining annual recurring cost, replacement cost, and salvage value, If infla­tion is constant at a rate i, costs at a future date of y years can be found by multiplying the cost by an inflation factor (IF) given by the equation

IF = (1 + i) у

Thus, the calculations can be made using costs that allow for inflation. Using this procedure, different costs can be adjusted for different levels of inflation, if there is information to support such choices. More complex methods for handling inflation are also available.

If the items being compared do not involve different annual costs, it is more direct to make the present worth calculation directly. Future nonrecurring costs over the project design life can be reduced to their present worth value by multiplying by the PW factor given above, PW = (1 + r)“n. These are added to the initial costs to determine total pre­sent worth of each system. The present worth of alternative systems can then be compared.

10.10.1 Example of Calculations

A simple example to illustrate the above calculation method is presented in Table 10.4. In this example, inflation is handled by using a net discount rate equal to the nominal discount rate (assumed as 10 percent) minus the rate of inflation (assumed as 5 percent). Two pipe materials are being considered for a drainage application where the project design life is 50 years. Initial costs associated with pipe A are \$150,000, and those associated with pipe B are \$180,000. Pipe A will require a \$37,400 rehabilitation at the end of 40 years, and pipe B a \$25,000 rehabilitation at the end of 45 years. Pipe A will have no salvage value, and pipe B will have a salvage value of \$30,000. For illustrative purposes, each is assumed to have an annual maintenance cost of \$1000. Calculations in part A show that for the assumed conditions, pipe A will have the lower annualized cost and the present worth of the difference in annual cost is \$24,900. Calculations in part B show the same difference in present worth, since the annual recurring costs are the same in this example. (For an example of LCC in pavements, see Art. 3.11.)

Life cycle costing is a technique to assess the total cost consequences between alternatives. The potential to optimize value through LCC is only as good as the alternatives being considered. It should be used in proper sequence as part of the VE effort.

(H. G. Tufty, Compendium on Value Engineering, Indo-American Society, Bombay, 1989; “Value Engineering and Least Cost Analysis,” Handbook of Steel Drainage and Highway Construction Products, AISI, Washington, D. C., 1994.)

## CATEGORIES OF COSTS

Costs that must be considered depend to some extent upon the system or project analyzed,

but can generally be categorized as follows:

1. Initial costs

a. Item costs. These are costs to produce or construct the item.

b. Development costs. These are costs associated with conducting the value study, testing, building a prototype, designing, and constructing models.

c. Implementation costs. These are costs expected to occur after approval of the ideas, such as redesign, tooling, inspection, testing, contract administration, train­ing, and documentation.

d. Miscellaneous costs. These costs depend on the item and include costs for owner-furnished equipment, financing, licenses and fees, and other one-time expenditures.

2. Annual recurring costs

a. Operation costs. These costs include estimated annual expenditures associated with the item such as for utilities, fuel, custodial care, insurance, taxes and other fees, and labor.

b. Maintenance costs. These costs include annual expenditures for scheduled upkeep and preventive maintenance to keep an item in operable condition.

c. Other recurring costs. These include costs for annual use of equipment associated with an item as well as annual support costs for management overhead.

3. Nonrecurring costs

a. Repair and replacement costs. These are costs estimated on the basis of pre­dicted failure and replacement of major system components, predicted alter­ation costs for categories of space related to the frequency of moves, and capital improvements predicted necessary to bring systems up to current stan­dards at given points in time. Each estimated cost is for a specific year in the future.

b. Salvage. Salvage value is often referred to as residual value. Salvage value is not really a cost, in that this factor is entered as a negative amount in the LCC calculation to reduce the LCC amount. Salvage value represents the remaining market value or use value of an item at the end of the selected LCC life span.

## Design Life

The first task one must accomplish in performing an LCC analysis is to determine the period of time for which the analysis of accumulated costs is to occur. This will usually be designated the project design life. The life span of the facility to be analyzed (a bridge, pavement, or culvert pipe) must be determined, together with the associated maintenance and rehabilitation costs. Another consideration that must be addressed is the realization that individual life spans of components of a system may be quite different. For example, in considering a highway system, the life of a bridge will likely be much longer than the life of a pavement. In considering a building, the life of the structural framework may well be 100 years or more, whereas the life of the roof may be only 20 years.

In performing a value study, the project design life or life span that should be selected is the period of time over which the owner or user of a product or facility needs the item. The user’s need determines the life span when judging LCC and worth, and when com­paring alternatives. The life span should be a realistic, reasonable time, and the same life span must be used for evaluating all choices. Assessment of obsolescence is part of a rational determination of design life. One must estimate how far in the future the functional capacity will be adequate. An unrealistically long design life may result in excessive expenditures on initial costs. On the other hand, an unrealistically short design life may lead to expensive replacement at a premature date.

The salvage or residual value at the end of the project design life must be determined and accounted for in the analysis. This may represent a net scrap value or the value asso­ciated with the reuse of a component, if that is feasible.

10.8.1 Discount Rates

The discount rate is used to convert costs occurring at different times to equivalent costs in present dollars. The selection of the discount rate to be used in the calculations is very important. If a low discount rate is selected, greater significance is given to future expen­ditures. If a high discount rate is selected, less significance is given to future expenditures. The discount rate should represent the rate of interest that makes the owner indifferent regarding whether to pay a sum now or at a future time. In government projects, the discount rate may be mandated by policy or law. The Office of Management and Budget prescribes rules for federal projects in Circular A-94. It states that the discount rate repre­sents an estimate of the average rate of return on private investment, before taxes and after inflation. Thus, it may differ from the cost of borrowing. Guidelines on discount rates may be further amplified by federal agencies.

## CONSIDERATIONS IN LIFE CYCLE COST ANALYSIS

Life cycle cost (LCC) is the total cost of ownership of an item, computed over its useful life. To rationally compare the worth of alternative designs, or different ways to do a job (accomplish a function), an LCC analysis is made of each. For those who follow the

VE job plan, a life cycle cost analysis is very easy to perform because the total impact of each recommended VE alternative is an integral part of the total calculations. In reality, an LCC study uses VE techniques to identify all costs related to the subject (functional) area, and VE’s special contribution can be the selection of the best alternatives to be “life cycle-costed.”

LCC is the development of all significant costs of acquiring, owning, and using an item, a system, or a service over a specified length of time. LCC is a method used to compare and evaluate the total costs of competing solutions to satisfy identical functions based on the anticipated life of the facility or product to be acquired. In performing a value study, an LCC analysis is performed in the development phase of the value engineering job plan to determine the least costly alternative.

The value of an item includes not only consideration of what it costs to acquire it, but also the cost to use it or the cost of performance to the buyer for as long as the item is needed. The buyer, not the seller, pays the life cycle costs and therefore must determine value. One measure of value to the buyer is the calculated total cost of ownership.

Costs of repair, operations, preventive maintenance, logistic support, utilities, depreci­ation, and replacement, in addition to capital cost, all reflect on the total value of a product to a consumer. Calculation of the LCC for each alternative during performance of a value study is a way to judge whether product quality is being maintained in sufficient degree to prevent degradation of reliability, performance, and maintainability.

Life cycle cost analysis requires the knowledge of several economic concepts. One of these is the concept of equivalent costs in relation to time. Equivalent costs are typically developed by equating all costs to a common time baseline using interest rates to adjust for variable expenditure years. One must also hold the economic conditions constant while the cost consequences of each alternative are being developed. That is, the same economic factors are applied to each alternative using a uniform methodology.

## COST MODEL

A cost model is a diagrammatic form of a cost estimate. It is used as a tool in the VE process to provide increased visibility of the cost of the various elements of a system or an item, to aid in identifying the item’s subelements most suitable for cost reduction attention, and to establish cost targets for comparison of alternative approaches. It also helps define the worth of an element.

A cost model is an expression of the cost distribution associated with a specific item, product, or system. In industry, it is often referred to as a work breakdown structure. A cost model is developed by first identifying assembly, subassembly, and major compo­nent elements or centers of work. From this, the model can be expanded to include a parts breakdown at more minute levels, as necessary. Next, the costs are developed (actual, estimated, or budgeted) for each of the above categories. These become the cost elements of the model and can be viewed as the cost building blocks of cost buildup from successive levels.

Shown in Fig. 10.3 are five common categories of cost for a government construction program. Some additional items that should be considered, particularly for a commercial project, include cost of land, financing charges, building permits, and taxes.

10.5 WORTH MODEL

The same form of model used to distribute cost of a system can be used to allocate worth. The cost model and the worth model should be identical in format. The procedures to follow in creating a worth model are as follows:

1. First, the VE team determines the necessary functions to be performed by each ele­ment of work at the lowest level of activity of the cost model.

2. The worth of each of these functions is determined as explained in the job plan.

Partition

drawings

Design changes

FIGURE 10.3 Cost model for construction program.

3. The worth of all functions for each cost element is totaled and becomes the worth for that element.

4. The sum of the worth of all cost elements becomes the worth of the corresponding cost element at the next higher level.

Thus, the VE team develops the minimum costs it believes are possible for each block of the cost model. The result is a cost model representing minimum costs. These costs become targets to be compared with costs as reflected by the best estimates available. Cost blocks having the greatest differences between target and estimated costs are then selected for VE study.

(H. G. Tufty, Compendium on Value Engineering, Indo-American Society, Bombay, 1989.)

## Diagramming Techniques

The following three considerations are general techniques that should be followed:

1. Usually only two FAST diagrams are of interest: the diagram that represents an exist­ing plan, program, or design, and the diagram that represents the proposed concept. When diagramming something that exists, be sure not to slip off on a tangent and include alternatives and choices that are not present in the existing system.

2. When using a FAST diagram to design or propose a new concept, restrict it to a specific concept; otherwise, the answers created in diagramming become meaningless. The “method selected” to perform a function brings many other functions into existence. Therefore, creation of several FAST diagrams during system design is a possibility.

3. The choice of the level of detail of functions to be used in the FAST diagram is entirely dependent on the point of view of the diagrammer, the purpose for which it is to be used, and to whom it will be presented. For presentation of VE study results to management, a very detailed FAST diagram should be simplified.

10.5.2 Summary of FAST Diagramming

1. FAST is a structured method of function analysis that results in analyzing the basic function, establishing critical path functions and supporting functions, and identifying unnecessary functions.

2. FAST diagrams should be constructed at a level low enough to be useful, but high enough to be advantageous to the purpose of creatively seeking alternative methods.

3. FAST diagrams are used to communicate with subject matter experts; to understand the problems of specialists in their own profession; to define, simplify, and clarify problems; to bound the scope of a problem; and to show the interrelated string of functions needed to provide a product or service.

4. The FAST procedure will be useful only if thinking outlined in the steps to pre­pare a diagram is performed. The value of this technique is found not in recording the obvious, but in the extension of thinking beyond usual habits as the study proceeds.

5. A FAST diagram, as first constructed, may not completely comply with “how” and “why” logic. This is because it takes additional thinking to get everything to agree. However, when you are persistent and insist that the logic be adhered to, you will discover that your understanding has expanded and your creativity has led you into avenues that would not otherwise have been pursued. When the “how” and “why” logic is not satisfied, it suggests that either a function is missing or the function under investigation is a supporting function and not on the critical path.

6. A main benefit from using FAST diagramming and performing an extensive function analysis is to correct our ignorance factor, so that we can see the study in its true light. Once this function analysis is performed on a given topic, we can quickly see that the only reason a lower-level function has to be performed is because a higher-level func­tion caused it to come into being. Essentially, whenever we establish one of these functional relationships that is visually presented by a FAST diagram, we correct our ignorance factor and open the door to greater creativity.

## Steps in Construction of FAST Diagrams

The following steps are recommended in the construction of the FAST diagram:

1. Function listing. Prepare a list of all functions, by assembly or by system, using the verb-and-noun technique of identification of function. Do this by brainstorming the questions (a) “What does it do?” and (b) “What must it do?”

2. The function worksheet. Using lined paper, prepare a three-column function work­sheet in the format shown in Fig. 10.2. Insert the listed functions from above, one at a time, into the central column. Then, ask of each function the following questions:

a. How do I (verb) (noun)? Record the answer(s) in the right column.

b. Why do I (verb) (noun)? Record the answer(s) in the left column.

FIGURE 10.2 Function worksheet for FAST.

3. The diagram layout. Next, write each function separately on a small card in verb – and-noun terminology. Select a card with the function that you consider to be the basic function. Determine the position of the next higher and lower function cards by answering the following logic questions:

a. Perform the “how” test by asking of any function the question, “How do I (verb) (noun)?” The function answer should lie to the immediate right. Every function that has a function to its immediate right should logically answer the “how” test. If it does not, either the function is improperly described or a function is in the wrong place.

b. The second test, “why,” works in the same way, but in the opposite direction. Ask the question “Why do I (verb) (noun)?” The answer should be in the function to the immediate left and should read, “So that I can (verb) (noun).” The answer must make sense and be logical.

4. The critical path. To determine whether a function belongs on the critical path, test the functions with these questions:

a. How is (verb) (noun) actually accomplished, or how is it proposed to be accom­plished?

b. Why must (verb) (noun) be performed?

5. The support logic block. A support logic block is a block immediately underneath a given block at the same general level of activity. This contains functions that “happen at the same time as” and/or “are caused by” some other function. They can be deter­mined by answering these questions:

a. When is (verb) (noun) performed?

b. If (verb) (noun) is performed, what else must also happen?

6. Locating the scope lines. In determining where to place the scope lines, the choice is arbitrary. Actually, moving the left scope line from left to right lowers the level of activity of the problem to be studied. The basic function to be studied shifts, since it is always the function that lies to the immediate right of the left scope line. Locating the right scope line determines the assumptions and “givens” one is willing to accept before starting the study. Location of both scope lines is also subject to the point of view of the owner or user of the problem.

See NCHRP Synthesis 352 for an example of a FAST diagram for a highway application.

## Guidelines for FAST Diagrams

Figure 10.1 depicts the diagramming conventions to be used in preparing a FAST dia­gram. The relative positions of functions as displayed on the diagram are also levels of activity. The FAST diagram is a horizontal graphical display based on system functions rather than system flowcharting or components. Level 1 functions, the higher-level func­tions, appear on the left side of the FAST diagram, with lower-level activity successively graphed to the right as shown. In most cases, when conducting a VE study, various levels of activity of verb-noun functions will be automatically suggested as the basic function of an item or a system.

The FAST diagram is just a tool. It is the process used in creating the diagram that is important, not the final diagram itself or its appearance. There is no such thing as a

“right” or perfect schoolbook solution that each diagrammer should be able to create, if he or she had perfect knowledge of the technique and theory. Yet if the diagram logic is logical to the diagrammer, it will normally be logical to a reviewer. And if it is not, then the FAST diagram will have served another purpose—communication of a misunderstanding in statement of the problem. That is also valuable to know. With these things in mind, consider the following guidelines in preparing a diagram:

1. Show the scope of the problem under study by two vertical dashed lines, one to the extreme left and one to the extreme right of the diagram. Everything that lies between the two scope lines is defined as the problem under study.

2. Every FAST diagram will have a “critical path of functions” going from left to right across the scope lines.

3. On that critical path should be found only required secondary functions, the basic function(s), and the higher-order function.

4. The higher-order function will lie to the immediate left of the left scope line.

5. The basic function(s) will always lie to the immediate right of the left scope line.

6. All other functions on the critical path will lie to the right of the basic function and will be the required secondary functions (not normally aesthetic or unwanted secondary functions).

7. Any “assumed” functions lie to the right of the right-hand scope line.

8. All other secondary functions the item performs will lie either above or below the critical path of functions. These functions can be required secondary functions, aesthetic functions, or unwanted functions.

9. If the function “happens at the same time as” and/or “is caused by” some function on the critical path, place the function below that critical path function.

10. If the function happens “all the time” the system is doing its work, place it above the critical path function to the extreme right of the diagram.

11. If there are specific design objectives or general specifications to keep in mind as the diagram is constructed, place them above the basic function and show them as dotted boxes.

12. All “one-time” actions are placed above the critical path and in the center area of the diagram.

13. All functions that lie on the critical path must take place to accomplish the basic func­tion. All other functions on the FAST diagram are subordinate to the critical path function and may or may not have to take place to accomplish the basic functions.

## FAST DIAGRAMMING AND THE JOB PLAN

Function analysis system technique (FAST) is a diagramming technique to graphically show the logical relationships of the functions of an item, system, or procedure. FAST was developed in 1964 by Charles V. Bytheway at the UNIVAC Division of the Sperry Rand Corporation. Prior to the development of FAST, one had to perform a function analysis of an item by random identification of functions. The basic function had to be identified by trial and error, and one was never quite sure that all functions had been uncovered. FAST provides a system to do a better job in function analysis.

10.5.1 Purpose of the FAST Diagram

The FAST diagram should be created during the information phase of the VE job plan by the whole VE team. When used in conjunction with a value study, the FAST diagram serves the following purposes:

1. It helps organize random listing of functions. When answering the questions “What is it?”, “What does it do?”, “What must it do?”, the study team develops many verb – noun function solutions at all levels of activity, which the FAST diagram can help sort out and interrelate.

2. It helps check for missing functions that might be overlooked in the above random function identification process.

3. It aids in the identification of the basic function or scope of the study.

4. It deepens and guides the involvement, visualization, and understanding of the problem to be solved and the proposed changes.

5. It demonstrates that the task team has completely analyzed the subject or problem.

6. It tests the functions through the system of determinate logic.

7. It results in team consensus in defining the problem in function terms and aids in developing more creative valid alternatives.

8. It is particularly helpful in “selling” the resulting changes to the decision makers.