Status of the Nation's Highways, Bridges, and Transit:
2002 Conditions and Performance Report
|Chapter 25: NHS Freight Connectors|
Part I: Description of Current System
Part II: Investment Performance Analyses
Part III: Bridges
Part IV: Special Topics
Part V: Supplemental Analyses of System Components
This chapter describes the investment requirements of National Highway System (NHS) freight connectors. NHS freight connectors are the public roads that lead to major intermodal freight terminals (the entire NHS system is described in Chapter 24). As noted in Chapter 22, freight transportation is critical to our Nation's economy, so it is important to understand the conditions and needs of freight connectors.
Summary of the Nation's Freight Connectors
The NHS freight connectors were designated in cooperation with State departments of transportation (DOTs) and metropolitan planning organizations (MPOs) based on criteria developed by the U.S. Department of Transportation. The criteria considered the level of activity of an intermodal terminal and its importance to a particular State.
A 2000 FHWA report to Congress on the condition and performance of intermodal connectors found that there were 517 freight-only terminals representing port (ocean and river), truck/rail, and pipeline/truck facilities. In addition to these freight-only terminals, 99 major freight airports (which handle both passenger and freight) were included in the list of freight intermodal terminals. Exhibit 25-1 displays NHS freight connector mileage by functional class and population density. It shows that the majority of mileage is in urban areas and is classified as arterials.
The report made several conclusions about physical deficiencies of these connectors. First, connectors to ports were found to have twice the percentage of mileage with pavement deficiencies when compared to non-Interstate NHS routes. Connectors to rail terminals had 50 percent more deficient mileage than non-Interstate NHS routes. Connectors to airport and pipeline terminals appeared to be in better condition with about the same percent of mileage with pavement deficiencies as those on non-Interstate NHS. This may be due to the high volume of passenger travel on airport roads.
Second, problems with shoulders, inadequate turning radii, and inadequate travel way width were most often cited as geometric and physical deficiencies with connectors. Data were not available to directly compare connectors and other NHS routes with regard to rail crossings, lane width, and other deficiencies. A general comparison of functional class attributes suggests that lane width, cross section, and design attributes are significantly more deficient when compared to non-Interstate NHS main routes.
The report to Congress, however, did not include an assessment of needed improvements or investment requirements. A follow-up effort was initiated in 2001 to develop an estimate of current investment needs for the NHS freight connectors based on deficiencies identified by the 1998 inventory conducted for the 2000 report to Congress. This estimate is described in the next section.
To estimate the investment needs of intermodal freight connectors, physical deficiencies were divided between “linear” and “spot.” Linear deficiencies are those that affect the connector along its length and typically are related to pavement, lane width, or number of lanes. Spot deficiencies are localized and typically related to an intersection, railroad crossing, or structure. The investment requirements analyses in Chapters 7 and 24 address some (but not all) of these deficiencies.
Exhibit 25-2 describes the logic employed to examine each connector with respect to the need for linear improvements such as pavement repair and/or expansion of capacity. The analysis first determined if additional capacity was needed based on the identification of congestion in the 1998 field inventory. Capacity needs were met by adding two lanes, unless the connector already had four lanes or more. If additional capacity was needed, then the condition of the pavement was checked to determine the appropriate course of action. If additional capacity was not needed, then requirements for additional lane width were examined. If additional lane width was needed, then the condition of the pavement and shoulder determined the final course of action.
Spot improvements were based on deficiencies involving isolated locations that could act as a bottleneck to the efficient flow of traffic along the connector. The survey identified spot deficiencies for: (1) structures that impose horizontal (width), vertical (height) or structural (weight limit) restrictions on the free flow of freight vehicles; and (2) highway intersections and railroad crossings that restrict the free flow of freight vehicles. The analysis identified spot deficiencies on each connector and used spot costs to estimate needed investments in addition to linear improvements.
Unit cost data for this analysis was obtained from a study currently being performed for the FHWA Office of Policy. That study, not yet completed, is designed to develop updated cost data for highway capital improvements for use in the HERS model. Costs are determined by highway functional class and improvement type. The improvement type initials used in the flow chart are also shown:
Linear deficiencies were assumed to exist for the entire length of the connector or identified segment. Some connectors were segmented in the inventory when geometry or pavement changed significantly. For these deficiencies, the unit cost for the identified improvement type was multiplied by number of lanes and number of centerline miles.
Exhibit 25-3 shows approximately one third (401 of 1,222 miles) of the connector system was judged to be in need of additional capacity. Of the remaining connector mileage, 579 miles needed pavement or lane width improvements, while roughly twelve percent (243 miles) were considered to have adequate pavement, lane, and shoulder width. Exhibit 25-4 shows the deficiencies by population grouping.
Only the existence and types of spot deficiencies were identified for each connector, so it was not always possible to determine the actual number of each type of deficiency on the connector. It was assumed that a positive indication of the existence of a deficiency meant that there was a single occurrence of the deficiency type on the segment. Exhibit 25-5 summarizes spot deficiencies.
of Freight Management and Operations, Federal Highway Administration.
The number of spot deficiencies on links with needed linear improvements is shown in Exhibit 25-6.
Two needs estimates were developed. The first addressed backlog or existing needs based on costs for the functional class. The table below shows the application of linear unit costs based on deficiency type over the length of the segment. This approach yielded the results shown in Exhibits 25-7 and 25-8.
The second needs estimate was done with the objective of raising the performance level of connectors (i.e., design standards) because of expected increases in the level of activity. The identification of improvement types was the same as that employed for the first estimate except that the unit costs for the next higher functional class was employed. An exception was the assumption that all connector mileage in need of pavement improvements used the reconstruction-minor unit cost because of increased design standards. As a result, the total cost in the category of “pavement work needed” represented a much larger proportion of overall program cost than the first estimate because the costs for the next higher functional class are greater [See Exhibits 25-9 and 25-10].
Spot Improvement Costs
In estimating costs for spot improvements, it was assumed that spot deficiencies occurring on links requiring major reconstruction or major widening were corrected as part of the linear improvement. Thus, the cost for these spot deficiencies was zero. Spot deficiency costs were estimated for other types of improvements and for links for which no other deficiencies were identified. The spot costs are shown in Exhibit 25-11.
Total NHS Freight Connector Investment Requirements
The cost for spot improvements was assumed to be the same for both the backlog needs and the costs for the enhanced connectors. Including the costs for spot deficiencies added $87.1 million to the total of both estimates. As shown in Exhibit 25-12, this resulted in a total cost for the backlog improvement estimate of $2.597 billion, while the cost for improving service due to expected increases in freight volumes would be $4.291 billion.