TDM Planning and Implementation
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Victoria Transport Policy
Institute
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Updated
22 July 2008
This chapter discusses various issues to consider when planning and implementing Transportation Demand Management programs. It describes basic planning principles and best practices. For more information see “Planning Principles and Practices” at www.vtpi.org/planning.pdf
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“The
one thing we need to do to solve our transportation problems is to stop
thinking that there is one thing we can do to solve our transportation
problems.” -Robert
Liberty, Executive Director, 1000 Friends of |
Levels of Analysis and Activity
Levels, Scales and Perspectives
Goals, Objectives,
Criteria and Performance Indicators
Geography (Transportation and Land Use Interactions)
Selecting and Evaluating TDM Strategies
References And Resources For More Information
Planning is the process of deciding what to do and how to do it. Effective planning allows people’s needs, preferences and values to be reflected in decisions. Planning occurs at many different levels, from day-to-day decisions make by individuals and families, to major decisions made by governments and businesses that have comprehensive, long-term impacts on society.
A basic principle of good planning is that individual, short-term decisions are coordinated in order to support strategic, long-term objectives. Comprehensive planning provides this coordination, allowing transportation, land use, economic development and social planning decisions to be coordinated.
Planning is a social activity – that is, it involves people, and the results are affected by who is involved and how they participate in the process. Good planning does more than simply identify the easiest solution to a particular problem. It can be an opportunity for learning, development and community building. For example, a planning process intended to address local traffic problem should identify neighborhood concerns, develop communication and trust between residents and officials, and create organizational networks for ongoing problem solving. This creates a framework for broad community development, and a way to identify and prevent potential problems. A constrained traffic planning process is likely to result in a few roadway projects that address the most acute problems, but does little to solve other residents’ concerns. A comprehensive community transportation planning process may result in a strategic program of pedestrian and cycling facility improvements, roadway projects, traffic safety programs, transit and community transportation services, and supportive land use policies, which help address traffic problems while also supporting a variety of other community development objectives.
Planning and management are similar activities: planning tends to involve a single decision while management tends to involve an ongoing decision-making process, but they often overlap.
Good planning coordinates short-term decisions to support long-term goals. In other words, good planning selects solutions to one problem that also help solve, or at least avoid exacerbating, other problems. For example, there may be many ways to reduce traffic congestion in a community. Some of these solutions may also help reduce other problems such as parking congestion, pollution and inadequate mobility for non-drivers, while other solutions may exacerbate these problems. Good planning identifies and accounts for these tradeoffs.
Most people don’t think too much about how their community came to be the way it is, how roadways are designed or why buildings are located where they are, but they are very aware of how will their community accommodates various forms of transportation, and will respond by choosing the mode that is most convenient. Community design can have significant impacts on individual’s travel options and behavior. The methods used to Model and Evaluate transportation activities and options can have a significant impact on transportation and land use planning decisions.
A particular planning decision can have a wide range of impacts, some of which are indirect or of concern to a particular group, and so may be overlooked or undervalued. The outcome of a planning process is significantly affected by how people are involved, interact and communicate. Different people may perceive a planning decision from many different perspectives, including those listed below. These are called stakeholders. How stakeholders are involved a key factor in the effectiveness of a planning process.
Stakeholders
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Users Citizens/taxpayers Impacted residents Businesses |
Employees/workers Public official Affected
organizations/interest groups. |
Planning requires explicit Prioritization of transportation activities to efficiently allocate resources. It gives higher value trips and lower cost modes priority over lower value, higher cost trips. For example, emergency vehicles, transit and freight vehicles tend to have relatively high value per vehicle-mile, and so can be given priority over private automobile travel (Basic Access). Transit, rideshare vehicles, bicycling and walking generally cost society less per passenger-trip than single occupant automobile travel (in terms of road space, parking costs, crash risk imposed on other road users and pollution emissions), and so should receive priority (Transportation Costs).
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Optimization Optimization refers
to solutions that provide the best balance between multiple, conflicting
objectives. Transport planning is sometimes reductionist (evaluation that considers just one or two
objectives), which can result in non-optimal solutions that may make society
worse overall. For example, decision-makers overwhelmed by the perceived
complexity of considering multiple planning objectives sometimes ask planners
to focus on just one or two problems. This can result in decisions that address
certain problems (such as congestion or pollution) which exacerbate other
problems (such as accidents and inadequate mobility for non-drivers), and
tends to undervalue solutions that provide multiple benefits. More comprehensive optimization tends to be best for society
overall. |
Good planning is forward-looking, based on a comprehensive, strategic, long-term vision of the outcomes that you want to achieve (Bartholomew, 2005). It involves more than simply extrapolating past trends (called “predict and provide” planning). It requires understanding the basis of change, modeling future impacts, and determining optimal responses. For example, it is poor planning to simply assume that current traffic and population growth rates will continue into the future, or that road capacity must be expanded to accommodate anticipated growth. Many factors may affect future growth rates, and management solutions may be the best way to meet community objectives.
Planning involves making decisions for the future, and therefore must deal with change and uncertainty. For example, it is not possible to know how changes in demographics, economics, technologies or consumer preferences will affect future travel patterns. As a result, it is difficult to predict exactly how much vehicle traffic will grow in the future. Even small differences in population and trip generation growth rates can have significant impacts on future travel and land use patterns. There are several ways to incorporate this uncertainty in decision-making. Predictions can describe ranges and probabilities rather than point estimates, and planning can incorporate contingencies and alternatives that response to different circumstances. For example, a community transportation plan may include various transportation improvements and management strategies, some of which will be only be implemented if traffic demand meets a certain threshold. TDM tends to be an important component of such Contingency-Based Planning.
Planners make a distinction between growth (increased quantity) and development (increased quality) (Sustainable Transport). In other words, growth means getting bigger while development means getting better. Development improves a community so that residents become wealthier, healthier, wiser and happier. Development involves using resources more efficiently rather than increasing resource consumption. Growth is not necessarily beneficial, and often imposes significant economic, social and environmental costs. Many of the problems associated with growth actually result from increased vehicle ownership and use. TDM allows communities to increase population and employment with fewer parking and traffic problems. For example, with conventional transportation patterns, infill development increases traffic and parking problems because each additional resident adds an additional car, but a successful TDM program can reduce per capita vehicle ownership and use, allowing additional population with fewer transportation problems. This can result in true community development, not just growth.
The scope of transport planning objectives tends to increase over time as people learn more about the broad range of impacts from transportation planning decisions. Older issues primarily concerned the accommodation of motor vehicle traffic. In recent years new issues have been added addressing various social and environmental concerns, although the older concerns have not diminished. As a result, transportation planners are forced to apply more Comprehensive Planning.
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Older Issues |
Newer Issues |
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· Roadway design and construction · Congestion reduction · Driver education and law enforcement · Traffic control and management · Vehicle parking · Traffic safety · Freight management · Transit service for non-drivers · Technological innovation (intelligent transportation systems) |
· Environmental concerns · Energy conservation · Equity – serving disadvantaged populations · Transportation demand management · Sustainability · Community livability · Land use integration (smart growth) · Security · Emergency response · Public health and fitness · ???? |
Planning requires resources (time, effort, money). In a typical project, 5-15% of the total budget is devoted to planning activities, and more if a decision affects many stakeholders or faces many obstacles.
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Transportation
System Design Vehicle What
“design vehicle” should be used for transportation planning? A car? A truck?
A bus? The
most important design vehicle is the human body. This means that facilities
and vehicles should be safe, comfortable, flexible, and easy to use by people
with diverse physical abilities and needs, including those are young and old,
big and small, who have disabilities, carry packages, travel in groups, have
pets, and cannot read the local language. A transportation system must serve
these diverse needs to be efficient and equitable. |
There are several levels of planning analysis and activity, listed below from the most general to the most specific. A good planning process usually begins with the most general concepts and leads to increasingly specific plans, programs and tasks, resulting in integration between each part.
·
Principles – A basic rule or concept used
for decision-making
·
Policies – A general course of
action.
·
Plans – A scheme or design of
action. This may be a strategic (general and broad) or an action (specific
and narrow).
·
Program – A specific organization
with a plan of action, usually with specific objectives, responsibilities,
staff and tasks.
·
Task or Action – A
specific thing to be accomplished.
Some important planning principles are listed below.
·
A clear decision-making process. Each set
in the process should be defined and understood by all stakeholders.
·
Stakeholder involvement. People who are
affected by a planning decision (“stakeholders”) should have opportunities to
become informed and involved.
·
Accurate information. Good
decision-making requires good information.
· A range of options to choose from. The greater the range of options that decision-makers have to choose from, the more likely they will be able to develop a plan that truly reflects their needs, preferences and values.
A planning process that fails to reflect these principles may result in confusion, conflict, disappointment and waste. As an example, imagine a process that offers just one choice for birthday celebrations: “Do you want a birthday party? If yes, instructions and a bill will be delivered shortly. Have a good time.” A more satisfying process allows individuals to help decide when and where their birthday party will take place, who is invited, the theme, decorations, and entertainment activities. It allows them to decide how much to spend, and what expenses should be added or subtracted to fit a desired budget. Of course, some or all of these decisions can be delegated, but an effective birthday celebration planning process allows individuals to affect their party to the degree they want. The resulting parties are likely to be quite different than a generic birthday party because they more accurately reflect the participants’ needs, preferences, values and creativity.
Planning occurs at many different levels and scales. Many planning decisions have direct and indirect impacts, which can be classified as below.
1. First level – Direct impacts (changes in travel conditions and costs).
2. Second level – Current
indirect impacts (changes in travel behavior, tax revenue, external impacts).
3. Third level – Long-term
indirect impacts (changes in land use, economic development).
For example, increasing roadway capacity has first-level impacts of reducing traffic congestion and increasing vehicle traffic speeds. A second-level impact is that the increased traffic capacity may attract additional travel from other routes and times (Rebound Effects), and it may create barriers to walking and cycling (Nonmotorized Evaluation). A third-level impact may be that over the long run, land use patterns become more dispersed and automobile dependent (Land Use Impacts).
Some geographic scales reflect natural areas and boundaries and others of which reflect political jurisdictions, as listed below. There are also temporal (time) scales: short-term usually refers to one or two years, mid-term usually refers to three to six years, and long-term usually refers to more than five years.
Table 1 Planning Scale
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Natural |
Political |
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Site Street Neighborhood Ecosystem/watershed Regional Global |
Special service districts Municipality/Regional government State/provincial Federal |
This table lists various scales used for planning, from the smallest to the largest.
These often overlap, and may reflect different economic, ecological and social perspectives. For example, a regional transport network usually overlaps many different political jurisdictions, watersheds, and human communities. To be effective, a planning process must account for these various geographic units. If a particular jurisdiction (such as a city or state) is making decisions that may affect people located outside its political jurisdiction, it is generally a poor practice to exclude those people from the planning process, since this can lead to unresolved conflicts, although their concerns may be given less weight than those of residents within the jurisdiction.
Goals are desired outcomes to be achieved, such as health, equity and happiness. Objectives are ways to achieve goals. Evaluation Criteria are impacts or factors to consider in the planning process and to incorporate into an evaluation framework, which may range from general to very specific (Evaluating TDM). Performance indicators are practical ways to measure progress toward objectives. These identify, what we want to achieve, how we will achieve these goals, and how we know whether we are making progress.
The ultimate goal of most transport is Access to goods, services and activities. Mobility refers to the movement of people and goods, and traffic refers to vehicle movement (Measuring Transportation). A transportation planning process that treats traffic improvements as a goal rather than an objective may overlook other ways to improve access, and result in decisions that degrade other forms of access.
For example, Transit Improvements and Rideshare Programs can result in more people traveling in fewer vehicles, Telework and Delivery Services can reduce the need for personal travel, and Location Efficient Development can reduce the distance between common destinations, reducing the amount of travel required for access. Increasing roadway and parking capacity can improve automobile access but often degrades access by walking, cycling and public transit. Conversely, Traffic Calming, some types of Pedestrian and Cycling Improvements, and more Clustered Development may reduce vehicle traffic speeds.
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Traffic, Mobility and Accessibility How
transportation is defined and measured can affect which solutions are
considered best. A particular policy or project may appear worthwhile when
transportation system performance is measured in one way, but undesirable
when it is measured another way. Conventional
transportation often reflects the assumption that transportation means motor
vehicle traffic. From this perspective, anything that increases motor
vehicle traffic speed and volume improves transportation, and anything that
reduces motor vehicle traffic speed and volume must be harmful. A
more comprehensive approach reflects the assumption that transportation means
personal mobility, measured in terms of person-trips and
person-kilometers. From this perspective, strategies such as better transit
services and rideshare programs may improve transportation without increasing
total vehicle-kilometers. However, this approach still assumes that movement
is an end in itself, rather than a means to an end, and increased personal
movement is always desirable. The
most comprehensive definition of transportation is Accessibility,
the ability to reach desired goods, services and activities. This is the
ultimate goal of most transportation, and so is the best definition to use in
transportation planning. It recognizes the value of more accessible land use
patterns and mobility substitutes such as telecommuting and delivery services
as ways to improve transportation while reducing total physical travel. Many
transport projects improve accessibility by some modes, but degrade it for
others. For example, increasing roadway capacity and traffic speeds tends to
improve access by automobile but reduces it by other modes, such as walking,
cycling and transit. Only by defining transportation in terms of
accessibility can these tradeoffs be considered in the planning process. Vehicle
traffic is relatively easy to measure, so transportation system quality tends
to be evaluated based largely on automobile travel conditions (e.g., average
traffic speeds, roadway Level-of-Service, vehicle congestion delay, vehicle
operating costs, parking supply), while ignoring other accessibility impacts,
including impacts on transit service quality, nonmotorized transport and land
use accessibility. This tends to favor automobile-oriented solutions, and
undervalues alternative solutions to transportation problems. |
Transportation planning goals should be broadly defined to include various economic, social and environmental outcomes that a community wishes to achieve. For example, goals might include improved Accessibility, support for economic development, improved opportunity for residents, equity, improved Safety and Health, and environmental protection. These can be defined for a specific geographic area or demographic group.
Transportation improvement goals are sometimes defined in terms of addressing a particular problem. For example, a TDM program may have a goal of reducing congestion or parking problems in a particular area. However, as described earlier, such a narrowly defined goal is actually an objective, since reducing a congestion or parking problem is not really an end in itself, it is a means to improve access to destinations. The danger with defining goals narrowly is that it limits the range of solutions and impacts that can be considered in the planning process. Planning based on narrowly defined goals and objectives allows solutions to one problem that exacerbate others (Comprehensive Transportation Planning). A variety of possible transportation planning goals and objectives are listed below.
Possible Transportation Planning Goals and Objectives
Transportation System Resilience
Improved Transportation Choice
Improved Transportation Equity
Energy Conservation and Emission Reductions
Improved Nonmotorized Transportation
More Efficient Land Use - Reduced Sprawl
Objectives are ways to achieve goals. There are different levels of objectives that can be used for TDM planning.
Transportation Demand Management uses the incentives listed in the table below to affect travel behavior. These can be considered the first-level objectives. For example, improving transportation choices, information and the relative speed and comfort of alternative modes can be considered TDM objectives if they are likely to change travel behavior in ways that help address transportation goals.
Table 2 Examples of TDM Program Incentives
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Mechanism |
Description |
Related TDM Strategy |
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Transportation choice |
Whether alternatives to driving exist. |
Transit, rideshare, shuttle services, walking, cycling, telework, carsharing. |
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Information |
Whether potential users can easily obtain accurate information about alternatives. |
TDM programs and marketing. Transit improvements. |
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Travel time |
Door-to-door travel time ratio between an alternative mode and driving. |
Transit improvements. HOV Priority. Pedestrian and cycling improvements. Traffic calming. |
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Convenience and comfort |
The relative level of convenience and comfort between an alternative mode and driving. |
Transit improvements. Walking and cycling improvements. |
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Price |
The relative financial costs between an alternative mode and driving. |
Market reforms, road pricing, parking pricing, distance-based charges, transit improvements. |
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Prestige |
Level of respect given by society to users of alternative modes. |
TDM Marketing. Pedestrian and bicycle promotion. Transit improvements. |
Second-level objectives are changes in travel behavior. TDM can affect travel scheduling (such as shifts from peak to off-peak periods), route, mode, destination, trip distance, trip frequency, use of mobility substitutes and vehicle ownership. For example, reductions in peak-period vehicle traffic volumes, per capita vehicle trip frequency or annual vehicle mileage may be considered TDM program objectives.
Third level objectives are desired outcomes that result from changes in travel behavior, including reductions in traffic congestion, crashes, pollution emissions and parking costs, and improvements in Basic Access (e.g., education and employment participation by people who are transportation disadvantaged).
Evaluation criteria are impacts or factors to considered in the planning process. Some, such as direct financial cost and vehicle travel, are relatively easy to measure. Others, such as equity and aesthetics, are more difficult to measure, but still important to consider. Various evaluation criteria and indicators can be used in TDM planning, such as those described in Table 3. TDM tends to have a wider range of impacts than other types of transportation improvements, and so requires a more Comprehensive Evaluation Framework.
Table 3 Examples of Evaluation Criteria and Indicators
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Criteria |
Indicators |
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Direct program financial impacts. |
Program costs per participant, per capita or per peak-period automobile trip reduced. Additional revenues from pricing strategies. |
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Direct consumer financial impacts. |
Financial costs and benefits, such as higher or lower user fees, or financial rewards. |
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Indirect financial impacts on governments and businesses. |
Changes in parking and roadway costs. |
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Indirect consumer financial impacts. |
Changes in vehicle operation and ownership costs. |
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Impacts on transportation objectives. |
Changes in peak period trips, per capita vehicle mileage, mode split, etc. (Measuring Transportation). |
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Impacts on transportation system performance. |
Average congestion delay, trip speeds, crash rates, pollution emissions. |
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Impacts on transportation choice and basic mobility objectives. |
Changes in Transportation Choice for various types of users (e.g. students, low income, non-drivers, etc.) |
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Impacts on Transportation Equity. |
Cost-based pricing, regressivity of price changes, improved access for transportation-disadvantaged people. |
Performance indicators are practical ways to measure progress toward objectives (Evaluation). A planning process can be significantly affected by the performance indicators that are used for evaluation. The table below illustrates various transportation quality indicators based on vehicle traffic, mobility and access. These different sets of indicators reflect different assumptions about the nature of transportation problems, and tend to favor different sets of solutions.
Table 4 Performance
Indicators (Measuring
Transportation)
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Traffic Oriented |
Mobility Oriented |
Access Oriented |
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Road system quality (e.g., roadway Level-Of-Service). Average traffic speed and congestion delay. Parking convenience. Vehicle use affordability. Vehicle-km crash and pollution rates. |
Transit service quality. Transit fare affordability. Rideshare Programs. Walk and bike facility quality. Transport system integration (e.g. ability to carry packages and bicycles on transit vehicles). Passenger-km crash and pollution rates. |
Door-to-door commute times. Portion of homes and worksites with shops, public services and transit within convenient walking distance. Quality and availability of telephone and Internet service. Quality of delivery services. Per capita total transportation costs and overall transport affordability. Per capita crash and pollution rates. |
The evaluation of TDM programs can be affected by the scale and perspective used for analysis. For example, a comprehensive Commute Trip Reduction program might reduce vehicle trips at participating worksites by 20%, representing 50% of downtown employees, where 10% of regional employees are located. Commute trips usually represent the majority of peak-period highway travel, but only about a third of total automobile travel. As a result, this program could be described as reducing 20% of trips a participating worksites, 10% of downtown commute trips, 2% of regional peak-period highway travel, or less than 1% of total regional travel. From a regional perspective the program may seem if little significance, although a major investment to increase highway capacity typically affects a similar portion of trips. As a result, it could be considered equal in value to a multi-billion dollar expenditure on new roads and parking facilities, and the most cost effective regional transportation investment.
Although most individual strategies have modest impacts, typically reducing travel by just a few percent, their effects are cumulative and synergetic. The most effective TDM programs usually include a combination of improved travel choices and incentives to reduce driving. Programs that include an appropriate combination of strategies can reduce peak-period driving at a particular location by 10-30%, and even greater impacts are possible if a combination of local, regional and state/provincial programs were implemented together (see TDM Programs and Comprehensive Market Reforms for examples). Since no North American community has implemented truly comprehensive TDM strategies, we don’t really know what the upper range of potential impacts would be.
Transportation and land use decisions have many interactive effects. Certain transportation patterns support a particular type of land use, and certain land use patterns support certain type of transportation (Evaluating Land Use Impacts). This occurs in many different ways and at many different scales. For example:
· Automobile-oriented land use patterns have abundant roadway and parking capacity, creating a more dispersed landscape that tends to be unsuitable for other forms of transportation. Multi-modal land use tends to be more clustered, with narrower streets and less land devoted to parking.
· Streets designed for automobile access have maximum lanes, driveways and parking (i.e. strip development), while streets designed for multi-modal access have good pedestrian conditions, and buildings clustered together.
· Automobile-oriented communities tend to have large areas that have single land uses (residential, commercial, etc.). Communities designed for multi-modal transportation have more mixed land use, with some commercial buildings within or near residential neighborhoods.
As a result, transportation and land use planning are two sides of the same coin. Planning analysis must recognize the Land Use Impacts of Transportation Decisions, and the Transportation Impacts of Land Use decisions. Some TDM strategies involve direct land use changes (Smart Growth, New Urbanism, Location Efficient Development, Transit Oriented Development), and others can have indirect but significant land use impacts (Parking Management, Traffic Calming). Many are affected by land use. For example, the design of a Commute Trip Reduction Program is affected by whether a worksite has a urban or suburban location, and what sort of amenities are located within convenient walking distance (because employees are more likely to use alternative commute modes if they can reach services such as restaurants and shops without a car). Conversely, efforts to reduce urban sprawl require TDM, since clustered, mixed land use is unlikely to be effective in areas with high levels of automobile use.
A planning process should be based on an overall problem or vision statement (these are essentially the same thing from opposite perspectives), and general goals. These determine specific objectives and evaluation criteria that will be used for prioritizing actions, programs, projects and tasks.
A. Problem
Statement, Vision and Goals
(examples: safety, health, mobility,
equity, economic development)
B. Objectives
(examples: teach safety, improve roadway
and trail facilities, increase non-motorized travel)
C. Evaluation Criteria
(examples: accident/injury rates, Bicycle
Compatibility Index, non-motorized travel rate)
D. Actions, Programs, Projects and Tasks
(examples: adopt design standards,
provide safety program, implement road and trail projects)
E. Program
Evaluation
(examples: did program achieve its stated
objectives? How is the program accepted by clients? What are its costs and
benefits?)
Planning is a social process that requires the involvement of people who ar