1739 McPherson St
Port Huron, MI 48060
ph: 810-858-2640
michael
Michael H. Schrader, P.E.
T2S2
Grand Prairie, Texas
April 2001
To the lay person, solving a traffic problem is a simple as putting up a sign or changing striping. To practitioners, changes are much more complex, and even the simplest change can affect other streets and entire neighborhoods. Changing how one street operates can, and often does, change how other streets operate. These operational changes can result in a long-term change in the quality-of-life and economic viability of the surrounding neighborhood. Thus, it is important when evaluating operational changes to evaluate not only traffic flow on the street in question but also throughout the entire network, and the effects such changes have on economic vitality and quality-of-life.
Such an approach was used to analyses potential changes to the 25th and 26th Street couplet system in Waco, Texas, to compare seven different operational concepts, four one-way and three two-way. Each of the seven alternatives was evaluated with respect to seven different criteria: Ease of implementation, construction cost, operation and maintenance (O&M) cost, traffic operation, traffic network impact, neighborhood “quality of life” (QOL), and economic impact (with respect to development and redevelopment). Each of the seven alternatives were comparatively ranked for each of these criteria, and the ranks were then summed for each alternative, with the alternative having the lowest rank sum being considered the most desirable, and the alternative having the highest rank sum the least.
THE EVALUATION CRITERIA
Ease of Implementation
Ease of Implementation pertains to how easily the alternative can be implemented with respect to preparation, logistics, equipment, personnel, time, and social and legal issues. Ease of Implementation is important because a good idea that is not implementable is merely a good idea, and does not provide any tangible benefits with respect to traffic flow, QOL, or economic impact. At the local level, is it politically and socially beneficial to be able to implement a plan within a relatively short time frame, i.e. less than two years. Plans that take longer than two years to reach fruition tend to lose support of both the citizenry and the decision makers. This is especially true in communities in which civic leaders are elected every two years, as entire governing bodies may change after two years.
Construction Cost
Due to the chronic fiscal constraints and capital shortages plaguing many local jurisdictions across the country, the construction cost, the cost of constructing the physical improvements necessary for the implementation of the alternative, is a necessary consideration when evaluating operational changes. No matter how beneficial to a community a project may be, if it cannot be funded, it cannot be built, and if it cannot be built, it yields no real and actuated benefit.
Operation and Maintenance Cost
One problem faced by many smaller jurisdictions is that of operation and maintenance costs, and the lack of resources to properly operate and maintain constructed infrastructure. For example, a small city may receive a grant to install a traffic signal, but may not have adequate funds to operate and maintain it, with the ultimate result being the eventual malfunction (due to lack of maintenance) or non-use (due to lack of operational funds) of the signal. Thus, the small city is no better off then before they received the grant—it still have the operational need for a traffic signal, but now it has a piece of equipment that could solve the problem that it cannot use. Unfortunately for the city, the political ramifications could be significant, as the lay person knows that the signal is not being used, but does not know why. Therefore, it is imperative to consider future operation and maintenance costs when evaluating a proposed change. In some instances, a proposed change may result in infrastructure (such as traffic signals) becoming moot and removable.
Traffic Operation
When analyzing proposed operational changes along a street or corridor, it is important to determine how the proposed changes will affect the quality of traffic flow along that street or corridor. The quality of traffic flow should not be confused with level-of-service, as the former encompasses much more than the latter. The traffic flow quality is impacted by the compatibility of the operation with the designated functional classification, speeds, multi-modalism, driveway location and frequency, lane widths, signal frequency and phasing, and vehicle characteristics.
Traffic Network Impact
As stated previous, changes in the operation on one street or corridor has an impact on the traffic operation of other streets and corridors, both adjacent and not, both crossing and not. For example, the elimination of parking on a street may divert vehicles onto other adjacent streets. The removal of a signal may cause a diversion to a parallel route several kilometers away. Because of the interaction and interdependence of all parts of a transportation network, it is essential to consider the impact on the transportation network as a whole of a change at one location.
Neighborhood “Quality-of-Life”
A traffic operational change to one facility can create such a dramatic change in travel patterns as to greatly effect the neighborhood “quality-of-life.” Creation of one-way couplet through a residential neighborhood can have a destabilizing impact on that neighborhood, as more traffic is introduced and the properties become less desirable for residential uses. The ultimate result of such a deterioration of property desirability is blight. Because of the real impacts traffic operational changes can make to a neighborhood, these “quality-of-life” issues should be considered when evaluation proposed operational changes.
Economic Impact
How traffic passes through a commercial area effects its viability. A high visibility location with good access is an essential ingredient to a successful commercial hub; correspondingly, locations with low visibility or that are hard to access are not conducive for commercial activity. As commercial establishments are vital to the stability of not only a neighborhood but also a city, projects that enhance a city’s commercial base should be viewed with higher regard than one that does not. Thus, the economic impact of a proposed change should also be considered in its evaluation.
THE EVALUATION METHODOLOGY
For 25th and 26th Streets, each of the seven different alternatives was compared to each of the seven others for each of the criteria and ranked accordingly. For example, the seven different alternatives were assigned a rank for “Ease of Implementation”, with the easiest given a rank of one and the most difficult a rank a seven, with each alternative given a different rank (i.e., no ties). The seven alternatives were then assigned a rank for “Construction Cost”, with the least expensive being assigned the lowest rank value, and the most expensive the highest. It is important to note that the alternative with the lowest ranking for the first criterion may or may not score the best for the other criteria; the ranking of a given alternative for each criterion is independent of the ranking of the same alternative for the other criteria.
For each alternative, the rank values for all criteria were summed. These sums were then compared to each other, with the alternative with the lowest rank sum being the best overall and the alternative with the highest rank sum the worst overall. For the Waco couplet, the individual and overall rankings are shown in Table 1.
TABLE 1: Summary Tabulation of rankings of Alternatives.
| ALT 1 | ALT 2 | ALT 3 | ALT 4 | ALT 5 | ALT 6 | ALT 7 |
Ease of implementation | 1 | 3 | 7 | 2 | 6 | 4 | 5 |
Construction cost | 1 | 6 | 7 | 2 | 5 | 3 | 4 |
O&M cost | 3 | 4 | 6 | 5 | 7 | 1 | 2 |
Traffic operation | 6 | 5 | 1 | 2 | 7 | 3 | 4 |
Traffic Network Impact | 5 | 6 | 3 | 4 | 7 | 2 | 1 |
Neighborhood “Quality of Life” | 5 | 3 | 6 | 4 | 2 | 7 | 1 |
Economic development | 6 | 3 | 4 | 5 | 2 | 7 | 1 |
RANK SUM | 27 | 30 | 34 | 24 | 36 | 27 | 18 |
RANK | 3 | 5 | 6 | 2 | 7 | 4 | 1 |
CONCLUSION
This methodology provided a tool for the City of Wacoto evaluate potential changes to the 25th and 26th Street Couplet. The City recommended the adoption of Alternative 7, which received the lowest rank score. This recommendation was presented to the public, media, and several elected representatives. By quantifying the various impacts, the City diffused criticism that it did not take into account the non-traffic impacts, so as QOL and economic impact, as well as criticism that the decision was based on the whims of the city staff. With the approval of the City staff and elected representatives, this same methodology was used to analyze proposed operational changes to Waco’s other one-way couplets.
OVERVIEW
A methodology for analyzing proposed traffic operation alternatives that provides quantification of seven different factors: ease of implementation, construction cost, operation and maintenance cost, traffic operation, traffic network impact, neighborhood "quality of life", and economic impact.
Originally submitted to the City of Waco, Texas, as a standard methodology for the analysis of one-way couplets.
Cite as:
Schrader, M.H. (2001) A holistic approach for evaluating proposed traffic operational changes. Total Transportation System Solutions.
Copyright 2018 Total Transportation System Solutions and Michael H Schrader, PhD, PE. All rights reserved.
1739 McPherson St
Port Huron, MI 48060
ph: 810-858-2640
michael