1.1 Basic Elements of Transportation Planning.pdf

Basic Elements of Transportation Planning To illustrate the transportation planning process, a situation that involves a rural road relocation project is described. (This example is based on a study completed by the engineering firm, Edwards and Kelsey.) Situation Definition Situation Definit...

Basic Elements of Transportation Planning To illustrate the transportation planning process, a situation that involves a rural road relocation project is described. (This example is based on a study completed by the engineering firm, Edwards and Kelsey.) Situation Definition Situation Definition. The project is a proposed relocation or reconstruction of 3.3 miles road of U.S. 1A located in the coastal town of Harrington, Maine. The town center, a focal point of the project, is located near the intersection of highways U.S. 1 and U.S. 1A on the banks of the Harrington River, an estuary of the Gulf of Maine. Situation Definition The town of Harrington has 553 residents, of whom 420 live within the study area and 350 live in the town center. The population has been declining in recent years; many young people have left because of the lack of employment opportunities. Most of the town’s industry consists of agriculture or fishing, so a realignment of the road that damages the environment would also affect the town’s livelihood. There are 10 business establishments within the study area; 20 percent of the town’s retail sales are tourism related The average daily traffic is 2620 vehicles/day, of which 69 percent represent through traffic and 31 percent represent local traffic. Problem Definition Problem Definition. The Maine Department of Transportation wishes to improve U.S. 1A, primarily to reduce the high accident rate on this road in the vicinity of the town center. The problem is caused by a narrow bridge that carries the traffic on U.S. 1A into the town center. Other causes are the poor horizontal and vertical alignment of the road within the town center, and a dangerous intersection where U.S. 1A and U.S. 1 meet. A secondary purpose of the proposed relocation is to improve the level of service for through traffic by increasing the average speed on the relocated highway. Problem Definition Basically the Goals of the project is to: 1. Reduce Accident Rate 2. Increase average speed The measures of effectiveness for the project will be : 1. Accident Rate 2. Travel Time 3. Construction Cost Problem Definition Other aspects that will be considered are the effects that each alternative would have on a number of businesses and residences that would be displaced, the changes in noise levels and air quality, and the changes in natural ecology. The criteria that will be used to measure these effects will be the number of businesses and homes displaced, noise levels and air quality, and the acreage of salt marsh and trees affected. Search for Solutions Search for Solutions. The Department of Transportation has identified four alternative routes, as illustrated in Figure 11.3, in addition to the present route— Alternative 0—referred to as the null or “donothing” alternative. All routes begin at the same location—3 miles southwest of the center of Harrington—and end at a common point northeast of the town center. The alternatives are as follows: Alternative 1 : This road bypasses the town to the south on a new location across the Harrington River. The road would have two lanes, each 12-ft wide with 8-ft shoulders. A new bridge would be constructed about one-half mi downstream from the old bridge. Search for Solutions Alternative 2 : This alternative would use the existing U.S. 1A into town, but with improvements to the horizontal and vertical alignment throughout its length and the construction of a new bridge. The geometric specifications would be the same as for Alternative 1. Alternative 3 : This new road would merge with U.S. 1 west of Harrington, and then continue through town. It would use the Route 1 Bridge, which was recently constructed. Geometric specifications are the same as those for the other alternatives Alternative 4 : This road would merge with U.S. 1 and use the Route 1 Bridge, as in Alternative 3. However, it would bypass the town center on a new alignment. Search for Solutions Analysis of Performance Analysis of Performance. The measures of effectiveness are calculated for each alternative. The results of these calculations are shown in Table 11.1 for Alternatives 1 through 4 and for the null alternative. The relative ranking of each alternative is presented in Table 11.2. For example, the average speed on the existing road is 25 mi/h, whereas for Alternatives 1 and 4, the speed is 55 mi/h, and for Alternatives 2 and 3, the speed is 30 mi/h. Similarly, the accident factor, which is now four times the statewide average, would be reduced to 0.6 for Alternative 4 and 1.2 for Alternative 1. The project cost ranges from $1.18 million for Alternative 3 to $1.58 million for Alternative 2. Other items that are calculated include the number of residences displaced, the volume of traffic within the town both now and in the future, air quality, noise, lost taxes, and acreage of trees removed. Analysis of Performance Analysis of Performance Analysis of Performance Evaluation of Alternatives Evaluation of Alternatives. Each of the alternatives is compared with the others to assess the improvements that would occur based on a given criterion. In this example, we consider the following measures of effectiveness and their relationship to project cost. Comparison of each Criterion o Travel Time. Every alternative improves the travel time. As shown in Figure 11.4, the best is Alternative 1, followed by Alternative 4. Alternatives 2 and 3 are equal, but neither reduces travel time significantly. o Accident Factor. Figure 11.5 shows that the best accident record will occur with Alternative 4, followed by Alternatives 1, 3, and 2. Evaluation of Alternatives Comparison of each Criterion o Cost. The least costly alternative is simply to do nothing, but the dramatic potential improvements in travel time and safety would indicate that the proposed project should probably be undertaken. Alternative 3 is lowest in cost at $1.18 million. Alternative 2 is highest in cost, would not be as safe as Alternative 3, and would produce the same travel time. Thus, Alternative 2 would be eliminated. Alternative 1 would cost $0.32 million more than Alternative 3, but would reduce the accident factor by 1.3 and travel time by 4.1 minutes. Alternative 4 would cost $0.04 million more than Alternative 1 and would increase travel time, but would decrease the accident factor. Evaluation of Alternatives Comparison of each Criterion o Air Quality. Alternative 1 would produce the highest air quality, followed by Alternatives 4, 3, and 2. The air quality improvement would result from removing a significant amount of the slow-moving through traffic from the center of the city to a high-speed road where most of the pollution would be dispersed. o Noise. Noise levels are lower for Alternatives 1 and 4 o Residences Displaced. Three residences would be displaced if Alternative 3 were selected; seven residences would be displaced if Alternative 2 were selected. No residences would have to be removed if Alternatives 1 or 4 were selected. Evaluation of Alternatives Comparison of each Criterion o Tax Loss. Tax losses would be slight for Alternatives 1 and 4, moderate for Alternative 3, and high for Alternative 2. o Trees Removed. Alternatives 3 and 4 would eliminate 25 and 28 acres of trees, respectively. Alternative 1 would result in slight losses; Alternative 2, no loss. Choice of Project Choice of Project. From a cost point of view, the Department of Transportation would select Alternative 3, since it results in travel time and safety improvements at the lowest cost. However, if additional funds are available, then Alterative 1 or 4 would be considered. Since Alternative 1 is lower in cost than Alternative 4 and is equal or better than Alternative 3 for each criterion related to community impacts, this alternative would be the one most likely to be selected. In the selection process, each alternative would be reviewed. Also, comments would be received from citizens and elected officials to assist in the design process so that environmental and community effects would be minimized. Choice of Project Specifications and Construction Specification and Construction. The choice has been made, and Alternative 1, a bypass south of Harrington, has been ranked of sufficiently high priority so that it will be constructed. This alternative involves building both a new bridge across the Harrington River and a new road connecting U.S. 1A with U.S. 1. The following technical documentation needed are as follows : The designs for the bridge and road, Detailed estimates of the cost to construct and The project will be announced for bid. The construction company that produces the lowest bid will be awarded the contract, and shall be given the Notice to Proceed or NTP and the road will be built. Upon completion, the road will be turned over to the Department of Transportation, who will be responsible for its maintenance and operation.