Traffic Analysis Toolbox Volume V:
Traffic Analysis Toolbox Case Studies – Benefits and Applications

3.0 Regional Transportation Plans and Programs

Large-scale planning efforts will clearly benefit from using the right traffic analysis tools. The questions to be answered in these efforts are basic ones: should the roadway be treated as an expressway or an arterial? How many lanes will be required? What's the best form of control for the intersections? Specially designed traffic analysis tools focus on the answers to these questions without getting lost in the costly and time-consuming details of operational and design considerations that will come later. Many such tools have been developed and can be effectively applied within the realms of sketch planning and travel demand modeling. The table below introduces two real-world case studies presented in the remainder of this chapter to demonstrate the benefits that can be achieved through the proper application of traffic analysis tools in regional transportation plans and programs.

Type of Analysis	Real-World Case Study
3.1 Sketch Planning	West Egan Drive Corridor Study Juneau, Alaska
3.2 Travel Demand Modeling	City-Wide Transportation System Plan Tualatin, Oregon

3.1 Sketch Planning Case Study – Corridor Refinement Study

Sketch planning traffic analysis tools are often used in regional transportation planning to analyze the impacts of regional growth trends on the transportation infrastructure. These tools can quickly and effectively evaluate the adequacy of roadway networks and intersections. As such, they also help in developing regional plans.

Effective and Adequate Evaluation Juneau's regional goal of balancing mobility with local access needs was more easily evaluated by using sketch planning traffic analysis tools, which are ideally-suited to a broad-level assessment of many individual intersections. A wide range of ideas and approaches was suggested by business owners, residents, and elected officials, and the sketch planning traffic analysis tools were used to quickly document the major impacts of each. By identifying likely areas of deficiency, the analysis tools also helped engineers and planners revise the initial concepts in ways that met the objectives of the stakeholders. Minimum Data Required, Easy to Understand Readily-available data were all that was necessary to apply the sketch planning traffic analysis tools. Model outputs were also very straightforward and easy to understand, resulting in consistent and effective communication of key findings with decisionmakers and the general public.

The use of the sketch planning traffic analysis tools provides basic intersection volume-to-capacity ratios and planning level intersection operational results.

With the help of these tools, numerous alternatives can be analyzed quickly and cost effectively. This allows alternatives to be discarded early in the process, with more concentrated efforts of analysis on the most viable alternative. Hence, these traffic analysis tools ensure efficient use of limited project resources.

Assisted in Decision Making Process Juneau's staff were able to screen alternatives on the basis of the sketch planning traffic analysis results by considering the effectiveness of the proposed alternative in conjunction with the anticipated costs. The infeasible alternatives from a cost or objective standpoint were discarded throughout the process before more detailed analysis was completed. More detailed evaluation was undertaken only after four viable alternatives were approved by the decisionmakers, leading to a final improvement plan that was consistent with the broader agency goals.

Stayed on Schedule Use of the sketch planning traffic analysis tool reduced the time necessary to select viable alternatives for more detailed analysis. As a result, the project was able to meet important deadlines for funding and implementation.

3.2 Travel Demand Modeling Case Study – Regional Plan Refinement

A regional travel demand model was used to help create a blueprint for the future transportation system in Tualatin, Oregon. Travel demand models are especially useful for this kind of activity because they take clear and direct account of the key factors that can be managed and controlled – population, employment, land use, and system characteristics. Alternative growth visions for the community were evaluated according to their impacts on congestion and quality of service.

Travel demand models can also be used to predict the traffic-related effects of alternative transportation policies and projections. Their ability to quantify the impacts of a particular policy or proposed improvement on congestion, infrastructure investment requirements, access to all modes, and quality-of-life issues can help to inform the decision-making that leads to the final adopted plan.

Travel demand models do not work at a level of detail that is sufficient to design and construct the identified improvements, but they provide the essential input other traffic analysis tools will need when the design effort is underway.

Subarea Analyses Tualatin needed to conduct a more detailed evaluation of several subareas within the city where zone changes were being contemplated. The travel demand forecasting model was used to "window in" on these subareas for a more refined analysis. Using this technique, the City was able to evaluate the local as well as the regional effects of their proposed plans.

Informed decision makers Tualatin's key decision-makers (City Council and Planning Commission) were kept updated through regular briefings that included colorful graphics from the travel demand model, showing the effects of various policy options on key performance measures like roadway volume and congestion levels.