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Data Collection and Use

III. How Is Data Used in Transportation Planning?

Through data and analysis, transportation planners can learn more about the conditions and needs of their transportation system. Examples of how data can be used in transportation planning include:

In transportation planning for Indian lands, Federal regulations require two major planning products: the Long-Range Transportation Plan (LRTP) and the Tribal Transportation Improvement Program (TTIP). The purpose of the LRTP is to develop a vision and goals that show a Tribe's transportation needs and anticipated strategies to meet those needs over the next 20 years or longer. The TTIP, in contrast, identifies the specific projects that will be implemented in the next three to five years to help move the Tribe towards meeting the vision and goals presented in the LRTP.

Long-Range Transportation Plan

The LRTP guides investment in the transportation system-the roads, sidewalks, bridges, and transit services used for travel. Strategies included in the LRTP should address future land use, demographic changes, economic development, travel demand, public safety, and health and social needs. The LRTP is expected to include projects that address short-term as well as long-term needs.

The LRTP answers questions about how the Tribe should invest its transportation money to create an efficient, safe, and durable transportation system. The questions might include:

Table 1 shows the types of data tribal planners use to develop the LRTP.

Category Examples of Useful Data
Demographic Data Current and projected:
  • Population
  • Age ranges
  • Gender breakdown
  • Average household size
System Inventory
  • Miles of roadway
  • Miles of paved roadway
  • Miles of sidewalk
  • Number of transit vehicles
  • Number of bridges
System Use
  • Traffic volume
  • Transit ridership
  • Number of pedestrians
  • Number of bicyclists
Physical Conditions and Operations Performance
  • Type of land use
  • Congestion
  • Physical condition of bridges
  • Age of transit vehicles

Demographic Data - Demographic data answers questions about the people currently using the transportation system and who might use the system in the future. Examining demographic data helps transportation planners determine whether the existing roadways, sidewalks, and other transportation facilities are sufficient for the current population and what changes should be made to accommodate population growth.

System Inventory - System inventory data answers questions about who owns or is responsible for each part of the transportation system. Answering these questions helps transportation planners compile information about the existing transportation system, classify roads by volume and condition, and identify system features such as bike paths and sidewalks. This data provides planners with a starting point for evaluating proposed projects with respect to the current transportation system.

System Use - Traffic and transit service data can answer questions about how people travel, such as the number of miles driven, the time of day of travel, and how they travel-car, bus, walk, or bike. Answering these and related questions helps transportation planners decide how roads and other transportation features should be changed to ensure good traffic flow and provide adequate transit service. This data helps planners decide where to locate new transportation investments such as new roads, expanded transit service, or additional sidewalks based on the number of people expected to use the facilities once they are in place.

Physical Conditions - Data on the condition of the bridges, pavement, and transit equipment answers questions about facility wear and tear and how the physical conditions of the transportation network affect travel, now and in the future. Answering these questions helps transportation planners assess a facility's remaining useful life and determine when it will need to be improved or replaced. Information on how land is used, such as for houses, shopping centers, crops, nature preserve-helps to answer questions about how a specific location's land use affects people's travel on particular roadways or transit services. Answering this and related questions allows transportation planners to identify where roads should be built and how land should be used to make it easier for people to get from their home to where they work, shop, or spend their leisure time. Planners can also use the data to minimize the impact that the transportation system has on natural resources and other sensitive areas.

Operations Performance - Operations performance refers to the use of the transportation system rather than its physical characteristics. Data on operations performance helps answer questions about congestion, safety, people's ability to access and use the transportation system, and how the operations performance of the transportation system affects people's ability to travel where and when they want. The answers to these and related questions help planners determine how to reduce the growth of congestion, make travel safer, and meet the transportation needs of everyone in the community.

Once data is collected, it should be analyzed to pinpoint the problems or needs that the LRTP should address.

Identify System Needs

Once data is collected, it should be analyzed to pinpoint the problems or needs that the LRTP should address. Looking at current or "baseline" conditions compared to the projected needs help to determine what changes will be necessary to meet the community vision and goals for the future transportation system. Table 2 shows examples of changes in transportation system characteristics over time and how the current system should be modified to meet the future needs. An analysis of a particular transportation system might include some or all of these categories and will also probably include others as well.

Select Projects and Strategies

In addition to determining system needs, data can also help a transportation planner evaluate project alternatives to find the most appropriate solution or project to include in the LRTP. The LRTP should include projects that are likely to be funded over the life of the plan and that help achieve the community vision and goals outlined in the plan. Data used to define goals or evaluate the transportation system performance is a good starting point for the project selection process.

Prioritize and Rank Projects

Once projects are selected, they must be prioritized. This is usually done based on two considerations: (1) the immediate need for the project and (2) availability of funding. Similar to the project selection process, data is often used to help demonstrate why one project should be a higher priority than others. For example, data might show that one roadway's condition is substantially worse than other roadways, making its reconstruction the highest priority.

Fund Projects

Besides relying on data to understand transportation needs, Federal, state, and other non-tribal agencies also use data to allocate funding. Financial data can help tribal transportation planners understand past trends in funding and project future funding. This data can also be used to estimate when funding might be available for specific projects and how much money will be available over both the short- and long-term.

Table 2 Analysis of Current and Future Conditions of a Transportation System

Category Current Condition Future Condition Change
Demographics Population: 10,000 Population: 15,000 Growth: 50 percent
Average Age - 40 Average age - 35 Population getting younger
Economic Development Employment: 7,500 Employment: 12,000 Growth: 60 percent
No Casino Casino in operation New employment center>
Economic Development Visitors' center planned Visitors' center completed New tourist attraction
Infrastructure 20 bridges rated adequate 15 bridges rated adequate headers="infra"5 bridges deteriorated
30 buses in operation 35 buses in operation
10 buses too old to operate safely and efficiently
5 additional buses are needed; 10 buses will need to be replaced
25 miles of walkway 50 miles of walkway 25 miles of additional walkway needed
50 miles of bikeway 75 miles of bikeway 25 miles of additional bikeway needed
System Use Average volume of 800 vehicles per day on main road Average volume of 1,000 vehicles per day on main road Growth: 25 percent
Vehicles drive a total of 2,000 miles per day Vehicles drive a total of 3,000 miles per day Growth: 50 percent
Transit average 100 passengers per day Transit average of 200 passengers per day Growth: 100 percent
5 percent of all trips are by walking 10 percent of all trips are by walking Growth: 100 percent
Operation 1 congested intersection 10 congested intersections 9 new congested intersections
3 intersections with traffic lights 10 intersections with traffic lights 7 additional intersections with traffic lights needed
15 traffic deaths per year 10 traffic deaths per year Decrease: 33 percent
2 deaths per 100 million total miles traveled by all vehicles per year 1.5 deaths per 100 million total miles traveled by all vehicles per year Decrease: 25 percent
5 pedestrian deaths per year 4 pedestrian deaths per year Decrease: 20 percent

Monitor and Revise LRTP

It is important to continually monitor data used in the LRTP to detect changes that could influence the projects or programs outlined in the plan. For example, a Tribe's current LRTP includes constructing new roadways and sidewalks for access to a new visitors' center. When the visitors' center and new infrastructure are completed, there is expected to be an increase in traffic to the visitors' center and on the surrounding roadway system leading to the new facility. Travel and traffic changes on the new facilities and the surrounding existing facilities should be tracked to understand the impact the new visitors' center is having on the transportation system as a whole. If more people are using the sidewalks, for example, this will probably affect traffic or transit use in the rest of the transportation system.

As another example, safety improvements made to some intersections have vastly improved safety and capacity of the main road in the community. This might reduce the number of crashes sufficiently so that other projects previously identified as needs are no longer necessary. As data becomes available and is collected and analyzed, it might be appropriate to make changes to the LRTP so that it better reflects the Tribe's ever-changing transportation needs.

It is important to continually monitor data used in the LRTP to detect changes that could influence the projects or programs outlined in the plan.

Use Data for Tribal and Indian Reservation Roads Transportation Improvement Programs

The TTIP and the Indian Reservation Roads Transportation Improvement Program (IRRTIP) are the short-range programs that prioritize projects over the next three to five years. Projects included in the TTIP and IRRTIP should be consistent with the goals and vision set out in the LRTP. As with the LRTP, data is critical to making informed decisions when prioritizing projects. For more information on these programs, see Transportation Decisionmaking Information Tools for Tribal Governments: Developing the Tribal Transportation Improvement Program at

Updated: 12/19/2013
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