The efficiency, reliability, and safety of the U.S. transportation system depend on assets that are properly maintained and in good physical condition as they perform their intended function of moving people and goods. This chapter examines the condition of the principal transportation modes, including infrastructure, vehicles and control systems, and the estimated cost of keeping or bringing the system into a state of good repair. Interconnections that link one mode with one or more other modes are also important system elements, but a lack of public data on these connections prevents meaningful analysis of their condition.

Roads, Bridges, and Vehicles

The U.S. Department of Transportation's (USDOT) Federal Highway Administration (FHWA) reports the International Roughness Index (IRI), which measures the smoothness of pavement and is a key indicator of the condition of highways and bridges.¹ Table 2-1 provides summary data on the percentage of rough surface mileage for different functional classes of highways. The physical deterioration of roads and bridges typically does not produce abrupt failures; rather, continued rough riding produces repetitive and gradual increases in vehicle maintenance and other highway user costs. In 2011, 13.9 percent of all rural roads and 35.3 percent of all urban roads had an IRI above 170, which is considered unsatisfactory [USDOT BTS 2014].

In urban areas the results are mixed. From 1999 to 2011, interstate highways, other expressways, and other principal arterials had 2 to 3 percent reductions in the mileage of road surfaces with an IRI above 170, with most of the improvement occurring after 2003. In contrast, over the same period, minor arterial and collector roads showed 10.4 and 15.8 percent increases, respectively, in the mileage of roads with an IRI above 170. One reason for the increase may be continuing commercial and residential development in many medium to large urban areas. The roadway infrastructure in such rapidly developing areas often consists primarily of local roads that were not built for the heavy trucks and high traffic volumes that come with development. The overall condition of all rural roadway categories improved between 1999 and 2011, with major collectors showing the greatest improvement (2.4 percent), although major collectors remained the only category with a double-digit percentage of mileage with an IRI above 170. Rural interstate highways and minor arterials had 1.8 and 6.6 percents of mileage, respectively, with an IRI above 170 in 2011.

There has been slow but steady improvement in the condition of highway bridges, as shown in table 2-2. Two categories of bridge deficiency are tabulated: structurally deficient and functionally obsolete. Structurally deficient bridges have reduced load bearing capacity due to the deterioration of one or more bridge elements. Such bridges are not necessarily unsafe, but they do require maintenance and repair to remain in service and will eventually require rehabilitation or replacement. Functionally obsolete bridges, while structurally sound, often carry traffic volumes that exceed their design limits and may need to be widened or replaced. Table 2-2 shows the percentage of structurally deficient bridges that declined from 2002 to 2012, with the largest decline recorded for rural bridges. There was a decline in the percentage of structurally deficient urban bridges and a decline in the percentage of urban traffic using structurally deficient bridges. Urban bridges carry 76.7 percent of all bridge traffic, a percentage that rose from 2002 to 2012. There was a small decline in the percentage of urban functionally obsolete bridges and a small decline in the percentage of urban traffic using functionally obsolete bridges. Despite the improvement, 24.0 percent of urban bridges were functionally obsolete for the years shown in the table.

Figure 2-1 provides additional information on deficient bridges by age group, although age alone is not an automatic indicator of structural integrity. For example, the 130-year-old Brooklyn Bridge is still deemed safe for daily use. However, in recent decades notable highway bridge collapses all involved structures that had been in place less than 35 years: the I-95 Mianus River Bridge in Connecticut, the I-87 Schoharie Creek Bridge in New York, and the I-35W Mississippi River Bridge in Minnesota [LITTLE 2013], which collapsed in 1983, 1987, and 2007, respectively. The trend, however, is clear—the likelihood that a bridge will be found deficient increases almost linearly with the age of the bridge. About one-half of bridges in place for 75 years or more are rated as deficient.

The more prevalent negative impact of bridge deterioration is the imposition of reduced load limits. In 2013 there were 71,692 bridges in the National Bridge Inventory with some type of load restriction, comprising 11.8 percent of all bridges listed [USDOT FHWA 2014]. These load limit reductions cause commercial vehicle operators to either use trucks with smaller payloads or take circuitous routes, both of which increase costs.

There is no organized database on the operating condition of vehicles traveling on the Nation's highways. Table 2-3 shows that the average age of the light-duty vehicle fleet increased by 28.1 percent over the 2001 to 2013 period and stood at about 11.4 years in 2013. Meanwhile, the heavy-duty commercial truck fleet, after increasing in age through 2010, is getting younger [POLK 2013]. In 2010, as replacement costs rose and the economic recession set in, the average age of freight trucks peaked at 6.6 years—a full year older than the long-term historic average of 5.6 years. Since the 2010 peak, the average age of freight trucks has been decreasing [CALPIN AND PLAZA-JENNINGS 2012] as the vehicle replacement rate accelerated with improvements in the U.S. economy. However, age cannot be used as a measure to gauge vehicle condition.

Traffic control systems, such as traffic signs, signals, and pavement markings, are an important element of the highway system, but there is no national database on traffic control systems and their condition. An estimated 311,000 traffic signals have been installed in the United States, with an aggregate public capital investment of $83 billion [NTOC 2012]. There are no comparable estimates of the numbers of other types of traffic control devices.

The biennial report on highway and transit system condition and performance prepared for the U.S. Congress by the USDOT contains detailed data, economic modeling, and analysis that highlight the relationships between physical condition, system performance, and investment.

Current annual capital spending on highways and bridges is set at $100.2 billion, which exceeds estimates on the amount needed to maintain current condition and performance. These estimates range from $65.3 billion to $86.3 billion per year, depending on future system usage as measured by vehicle-miles traveled (VMT). These estimates indicate that sustained spending at current levels could result in improved system conditions and performance, but falls short of the $123.7 billion to $145.9 billion per year that FHWA estimates is needed to rehabilitate, expand, and enhance the system [USDOT FHWA and FTA 2013].

Public Transit

Table 2-4 provides information on the condition of rail transit infrastructure for 1997 and 2006, the latest year for which data are available. Elevated structures, such as rail transit bridges, viaducts, and tunnels, had the highest percentage of facilities rated good or excellent, and both showed an increase in the latter rating category over the reporting period. In most of the infrastructure categories, condition ratings tended to move toward "adequate," rather than "better" or "worse." Communication systems (telephones, radios, and computer networks) achieved the best overall ratings, with over 99 percent rated as adequate or higher, and this category had the highest increase in the percentage of systems rated as excellent.

The average age of transit vehicles over the 2001 to 2012 period is shown in table 2-5. Commuter rail locomotives and passenger coaches aged the most among rail vehicles over that period and are among the oldest of all transit equipment. The heavy-rail car fleet age decreased by 1.9 years between 2001 and 2012, but is still 19.8 years old on average, the oldest part of the rail and transit fleet. Lightrail vehicles maintained an average age of about 15 to 16 years over the reporting period. The transit bus fleet aged slightly, indicating that many transit agencies retired and replaced older buses. As would be expected, the transit bus fleet remains considerably newer than the rail fleet, which has locomotives and cars that may last for decades.

Maintaining urban transit vehicles in good condition requires maintenance facilities that are well suited to the task. Table 2-6 shows that most maintenance facilities are rated as adequate or better, but 465 bus maintenance facilities (36.3 percent of the total) and 53 rail facilities (26.4 percent) were rated as substandard or poor in 2006, the latest year for which data are available. For both bus and rail, the biggest increases over the 2002 to 2006 period occurred in the excellent and substandard or poor facilities categories.

There appears to be a direct relationship between public transit system condition and performance and transit ridership (see e.g., GRAVA 2002 for detailed discussions of the ridership history of each transit mode). Deferred maintenance, outdated equipment and passenger stations, and numerous stops produce an overall transit image that may discourage prospective riders. Conversely, modern, well designed and maintained systems might attract riders who would otherwise travel by other means.

According to USDOT's biennial conditions and performance report, the current total investment across all transit systems is $16.5 billion annually. Bringing all systems to a state of good repair would require an increase to $18.5 billion per year. However, increasing system capacity to accommodate higher transit ridership would require an estimated $22.0 billion to support a 1.4 percent growth rate versus an estimated $24.5 billion to support a 2.2 percent growth rate [USDOT FHWA and FTA 2013].

Railroads

Intercity Passenger Rail

Amtrak owns a small fraction of its 21,300 route miles, primarily 363 miles of the 456- mile Northeast Corridor between Boston, MA, and Washington, DC, plus three other shorter segments totaling 261 miles [AMTRAK 2012b]. The vast majority of passenger train services outside the Northeast Corridor are provided over tracks owned by and shared with the Class I freight railroads.² Hence, the condition of the infrastructure Amtrak uses is largely dependent on the condition of the host railroads, with the exception of the Northeast Corridor.

Amtrak owns, operates, and maintains its own rolling stock. Table 2-7 shows the ages of most of Amtrak's passenger cars and locomotives. The four largest groups of passenger cars range in age from 16 to 64 years and have accumulated an average of more than four million miles per car. The locomotive fleet and trainsets (e.g., Acela) are younger, ranging in age from 12 to 32 years. Amtrak is in the process of acquiring 70 new electric locomotives to create a homogenous fleet by replacing all of its aging AEM-7 units as well as the relatively new HHP-8 locomotives,³ which have reliability issues. Amtrak is also purchasing 130 new long-distance railcars to replace its vintage Heritage cars and increase capacity [AMTRAK 2012a]. These and other upgrades should decrease the average age of the fleet.

Freight Rail

The U.S. freight rail system is privately owned and operated, and rail carriers are under no obligation to report freight track conditions to public sector agencies. Thus universal track condition reports are unavailable. Railroads are responsible for ensuring track safety, and to that end they regularly inspect their track and perform necessary repairs. The Federal Railroad Administration (FRA) regulations require railroads to maintain track inspection records and make them available to FRA or state inspectors on request. The FRA's rail safety audits focus on regulatory compliance and prevention and correction of track defects. Presently, there is no regular program for assembling and analyzing the many thousands of inspection reports that are prepared each year.

There is, however, one FRA program that generates systematic data on track condition. The Automated Track Inspection Program (ATIP) utilizes a small fleet of highly instrumented track geometry inspection cars to survey tens of thousands of miles of high traffic density and other high priority routes each year. Table 2-8 provides a summary of the inspection results for the years 2004 to 2011. Of the eight track characteristics that are monitored, the incidence of three–gage, crosslevel, and warp—are lower in more recent years than in earlier years, but other results are more variable.

The installation of new rail and crossties is one indicator of how track conditions are maintained and improved. The Association of American Railroads (AAR) reported that the Class I railroads installed nearly 790,400 tons of rail and 15,853,000 crossties in 2012, which is more than the annual average of 713,200 tons of rail and 15,050,000 crossties from 2007 to 2011 [AAR 2014].

The AAR also provides data on the age of the seven Class I railroad locomotive fleets (table 2-9). More than 4,500 locomotives were added during the 2001 to 2011 period, reducing the median age of the fleet from 19 to 14 years. No comparable compilation of the age distribution of railcars is available.

Table 2-10 shows railroad capital expenditures trends. As shown, capital expenditures totaled $11.6 billion in 2011, more than doubling the spending in 2001. In contrast, revenue tonmiles increased 15.7 percent over that period. Freight rail is a profit-making enterprise that self-funds its investments, and carriers have a strong incentive to maintain, rehabilitate, and upgrade their systems as needed to remain competitive in the market place and earn returns for their investors.

Ports and Waterways

Dams and navigation locks are two of the principal infrastructure features of the U.S. domestic waterway transportation system. They enable shallow draft operations on most rivers. The principal exceptions are the Lower Mississippi River and the Missouri River, which are free-flowing but still require some types of hydrologic structures, such as large rock and concrete groins and revetments, to manage the flow of the river and preserve navigation. The U.S. Army Corps of Engineers (USACE) owns and operates 239 lock chambers at 193 sites, which account for most of the U.S. inland navigation locks. The average age of all locks is over 50 years [USACE 2012]. The USACE maintains comprehensive data on lock traffic, lockage time and delay, and lock outages for waterway performance analysis.

Table 2-11 provides data on representative locks throughout the inland waterway system. These data show some of the relationships between lock age and performance factors such as tow delay and lock chamber downtime. For example, the Emsworth Lock on the Ohio River is one of the oldest structures in the system and is considered functionally obsolete. It has lock chambers designed for vessels of an earlier era and has lengthy out-of-service delays. The newer locks on the Ohio River, such as John T. Myers, are larger and had relatively low average tow delays of about 40 minutes in 2013 and tend to have numerous short-duration service outages. Lock 52 on the Ohio River is the busiest and also one of the oldest with chambers that are 45 years and 86 years old. It had one of the highest average tow delays in the entire inland waterway system, 8.6 hours in 2013.

On the Upper Mississippi River, the Melvin Price Lock has the two newest lock chambers listed in table 2-11. It passes over 40 million tons of freight per year with little delay or downtime. Just 15 miles downstream, Lock 27, with two identical size but much older chambers (61 years), has an average tow delay that exceeds 6 hours. The Inner Harbor Navigation Lock, in New Orleans, is one of the principal bottlenecks in the Gulf Intracoastal Waterway. The small chamber size of the 91-year-old lock results in an average tow delay of more than 12 hours.

Shallow and deep-draft ports and channels are other important infrastructure elements of the waterway system. There are several thousand inland river ports and terminals, the vast majority of which are privately owned and serve very specific cargo-handling needs (e.g., coal loading and petrochemical transfers). Deep draft ports are large and capital-intensive facilities, typically with extensive docks, wharves, cranes, warehouses, and other cargo transfer equipment and intermodal connections that integrate ocean transport with inland connectors. Private terminal operators do not routinely release data publicly on the condition of their facilities. The USACE maintains an extensive database of marine terminals, both shallow draft and deep draft, but it is largely static and does not include condition or performance data items and summary tabulations.

The main characteristic of navigation channels that relates to condition is whether the authorized depth is actually available. Nearly all channels need periodic dredging to maintain the authorized depth. Most channel dredging occurs under the auspices of the Army Corps of Engineers. In 2012 the Corps' and contractor's dredges removed 238 million cubic yards of material, up from 228 million in 2011. In 2012 maintenance dredging accounted for 84.0 percent of the removed material; the average cost per cubic yard decreased 15.6 percent to $3.99 [USACE 2013]. The Corps maintains detailed dredging data, but it does not produce summary tabulations that differentiate the work by deep or shallow draft channels.

U.S. flag vessels operate on both shallow and deep draft waterways and numerous foreign flag vessels call at deep draft ports. Table 2-12 provides age distributions of U.S. flag vessels for the 2001 to 2011 period. Inland waterway towboats and barges account for the largest share of U.S. vessels. Towboats are the oldest vessels in this assemblage; 71 percent are older than 25 years, which is their median age. In contrast, barges are among the youngest vessels due to a combination of retirement and replacement of older dry cargo barges and acquisition of new tank barges. This is largely in response to the Oil Pollution Act of 1990 (Pub. L. 101-380) that decreed tank barges and vessels must have double hulls by January 1, 2015. The U.S. Maritime Administration reported that the average age of ocean vessels per call at U.S. ports decreased from 11.2 years in 2006 to 9.7 years in 2011 [USDOT MARAD 2013].

While there is no definitive list of waterway transportation system investment needs, several recent studies have made estimates. A Congressional Research Service study estimated that the Corps' navigation project backlog amounted to $60 billion [CRS 2011]. Based on the fact that navigation projects account for one-third of the Corps' 2012 budget, the American Association of State Highway and Transportation Officials (AASHTO) estimated the agency's navigation project backlog totaled $20 billion [AASHTO 2013].

Aviation

The main elements of the aviation system include airport runways and terminals, air traffic control systems, and aircraft. The Federal Aviation Administration (FAA) compiles data on runway pavement conditions, which are presented in table 2-13. Most airport pavements were in good condition between 2003 and 2013, with 2 percent in the poor category. There are no similar data for other elements of aviation infrastructure.

The Airports Council International (ACI) surveyed its U.S. members to ascertain their capital project needs for the 2013 to 2018 period. The survey indicated a total need of $71.3 billion. Age and technological obsolescence are likely the drivers for much of this need, as many airports were built more than 40 years ago. Terminal improvements at large hub airports account for 50 percent of projected investment needs, while runways, taxiways, and aprons will need 55 percent of investment dollars at medium and small hubs [ACI 2013].

The FAA is in the midst of a major effort to upgrade the U.S. air traffic control (ATC) system to increase its capacity. A major reason for this effort is that the ATC system relies on ground-based radar and voice communication technologies that date to the 1940s, which limit its ability to increase capacity in line with increasing air traffic demand. Current FAA efforts are focused on developing the Next Generation Air Transportation System (NextGen), which will utilize GPS satellite technology and related communications and information technology improvements.

Figure 2-2 shows average ages of U.S. commercial aircraft from 2006 to 2011. The average age increased to 13.3 years in 2011, up from 11.8 in 2006. While the period of review spanned five years, the average age increased by only 1.5 years, indicating some fleet turnover occurred from 2006 to 2011. Turnover generally refers to new aircraft entering service and/or older aircraft retiring from the fleet.

Pipelines

The Pipeline and Hazardous Materials Safety Administration (PHMSA) collects annual report data from pipeline operators, covering their system mileage, commodities transported, and inspection activities, but there is no publicly available database that tracks pipeline condition. A serious failure, such as the Pennsylvania pipeline failure in January 2011, serves as a reminder that this part of the transportation system has the same problems with aging infrastructure as the other modes profiled in this chapter [USDOT PHMSA 2014].

Table 2-14 shows the gas distribution mains and transmission lines and Hazardous Material (HAZMAT) pipeline miles installed as of 2013 by decade since 1940 as well as the pre-1940s mileage. Gas distribution mains have 12.4 percent installed pre-1940s or unknown, followed by HAZMAT with 7.2 percent, and gas transmission lines with 4.2 percent. Pipeline construction boomed during the 1950s and 1960s when 46.2 percent of the today's existing gas transmission lines and 36.8 percent of the HAZMAT pipeline were installed.

Challenges

As with railroads, pipeline companies are private enterprises that are responsible for their own system maintenance, rehabilitation, and expansion. Hence, there are little data or estimates available on systemwide capital investments.

With the largest transportation system in the world, the United States faces a continuing challenge of maintaining system conditions in sufficiently good shape to meet the enormous mobility requirements of the American economy and society. As indicated earlier, the condition of transportation infrastructure is improving, but additional improvements are needed. The average age of all inland waterway navigation locks is more than 50 years, and 11.0 percent of bridges are considered structurally deficient. If these condition issues are not addressed, they could affect system performance in the coming years.

References

Airports Council International (ACI). 2013. Airport Capital Development Needs 2013- 2017, January. Washington, DC. Available at http://www.aci-na.org/ as of November 2013.

Association of American Railroads (AAR). Ten-Year Trends 2004-2013 (May 2014). Washington, DC. Available at https://www.aar. org/ as of June 2014.

American Association of State Highway and Transportation Officials (AASHTO). Waterborne Freight Transportation Bottom Line Report, June 2013. Washington, DC.

Calpin, P. and E. Plaza-Jennings. A Look Back at EPA's Cost and Other Impact Projections for MY 2004 - 2010 Heavy Duty Truck Emissions Standards. Exhibit B in NADA Comments To NHTSA/EPA Re: MY 2017 - 2025 Proposed Standards, Doc Nos. NHTSA–2010–0131 and EPA–HQ–OAR–2010–0799, February. Available at http://www.nada.org as of November 2013.

Congressional Research Service (CRS). Army Corps Fiscal Challenges: Frequently Asked Questions, August 2011. Library of Congress, Washington, DC.

Grava, S. 2002. Urban Transportation Systems. McGraw-Hill, New York, NY.

Little, Richard G. Enjoying the Golden Years: Coping with the Challenges of Aging Infrastructure. The CIP Report, Vol. 12, No. 3, September 2013. Center for Infrastructure Protection and Homeland Security, School of Law, George Mason University, Arlington, VA. Available at http://cip.gmu.edu as of November 2013.

National Railroad Passenger Corporation (AMTRAK):

—2012a. Amtrak Fleet Strategy, March 2012. Washington, DC. Available at http://www. amtrak.com/ as of November 2013.

—2012b. National Fact Sheet: FY 2012. Washington, DC. Available at http://www. amtrak.com/ as of November 2013.

National Transportation Operations Coalition (NTOC). 2012 National Traffic Signal Report Card Technical Report. Institute of Transportation Engineers, Washington, DC. Available at http://www.ite.org/ as of November 2013.

R.L. Polk & Co (POLK). Quarterly Commercial Vehicle Report, June 2013. Available at https://www.polk.com/ as of November 2013.

U.S. Army Corps of Engineers (USACE). The U.S. Waterway System: Facts and Information, November 2013. Navigation and Civil Works Decision Support Center, Alexandria, VA. Available at http://www.navigationdatacenter. us/ as of November 2013.

U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS), National Transportation Statistics, Table 1-27. Available at http://www.bts.gov/ as of January 2014.

U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA) and Federal Transit Administration (FTA). 2013 Status of the Nation's Highways, Bridges, and Transit: Report to Congress (Washington, DC). Available at http://www.fhwa.dot.gov/ as of November 2013.

U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA). 2014. National Bridge Inventory, Bridges by Posting Status, 2014. March. Washington, DC. Available at http://www.fhwa.dot.gov/ as of April 2014.

U.S. Department of Transportation (USDOT), Maritime Administration (MARAD). 2013. Vessel Calls Snapshot, 2011. Available at http:// www.marad.dot.gov/ as of November 2013.

U.S. Department of Transportation (USDOT), Pipeline and Hazardous Materials Safety Administration (PHMSA). 2014. Serious Pipeline Incidents By Cause. Available at http://primis.phmsa.dot.gov/ as of November 2013.

¹ A highway that has a roughness rating greater than 170 inches per mile is considered in poor condition.

² Includes BNSF Railway, CSX Transportation, Grand Trunk Corp., Kansas City Southern, Norfolk Southern, Canadian Pacific operations in the United States, and Union Pacific.

³ AEM-7 and HHP-8 are a type of twin-cab electric locomotive.