Chapter 4 Freight Transportation System Performance
The efficient and reliable movement of goods is important to the U.S. economy. Truck travel time and speed are two indicators of transportation system performance. Slower speeds and unreliable travel times caused by congestion and inclement weather conditions increase fuel cost and affect operations efficiency and productivity.
Figure 4-1. Average Speeds on Select Interstate Highways: 2014
The U.S. Department of Transportation, Federal Highway Administration, in cooperation with private industry, measures the speed and travel-time reliability of more than 500,000 trucks on 25 freight-significant corridors on an annual basis. Average truck speeds drop below 55 miles per hour (mph) near major urban areas, border crossings and gateways, and in mountainous terrain.
Table 4-1. Maximum Posted Speed Limits on Rural Interstates: 2015
Delay, reliability, and similar performance measures are typically based on the difference between speed limits and actual speeds. Speed limits for trucks (table 4-1) vary from state to state and are lower than limits set for passenger vehicles in seven states.
Table 4-2. Average Truck Speeds on Selected Metropolitan Area Interstates: 2012-2015
The Federal Highway Administration uses Freight Performance Measurement Program data to measure truck speeds within 14 very large Census Metropolitan Statistical Areas. In 2015, 7 of the 14 metropolitan areas had average truck speeds of less than 55 mph on their roadways.
Table 4-3. Performance Measurements for Selected Corridors on Weekdays: 2014
The Federal Highway Administration Freight Performance Measurement Program monitors performance on corridors that have the heaviest freight volumes. Measuring average speed during peak and nonpeak periods of travel is beneficial in understanding freight performance on these corridors and identifying areas in need of operational and capital improvements.
Table 4-4. Top 25 Congested Freight-Significant Locations: 2013
Truck speed and travel time reliability data can be used to identify and quantify major freight truck chokepoints and bottlenecks along highways critical to the Nation’s freight transportation system. The Federal Highway Administration developed a freight congestion index that ranks congestion’s impact on freight movement. The index factors in both the number of trucks using a particular highway facility and the impact that congestion has on the average speed of those vehicles.
On weekdays, average speeds during peak periods (between 6:00 a.m. and 9:00 a.m. and between 4:00 p.m. and 7:00 p.m.) are typically less than those recorded during nonpeak periods. Freight traveling across urban interstate interchanges is affected to the greatest degree by peak-period congestion. At several locations, congestion affects freight mobility during all hours of the day.
Table 4-5. Largest Improvements in Average Speed for Congested Freight Highway Locations: 2012-2013
Several monitored locations have recorded noticeable improvements in performance from 2012 to 2013 when considering average speed over a 24-hour period. Locations along I-95 in New Jersey and Delaware have seen the greatest improvement in overall and nonpeak period average speeds.
Intercity travel-time reliability is a key freight performance measure. It influences logistics, operational strategies, and load optimization. The Federal Highway Administration analyzed the truck trip reliability of key city-pair origins and destinations. Travel time between Philadelphia and New York City and between San Francisco and Sacramento showed the greatest change. Drivers in all city pairs shown in table 4-6 experienced increases in travel time.
Figure 4-2. Peak-Period Congestion on the National Highway System: 2011
Recurring congestion caused by volumes of passenger vehicles and trucks that exceed capacity on roadways during peak periods is concentrated primarily in major metropolitan areas. In 2011 peak-period congestion resulted in traffic slowing below posted speed limits on 13,500 miles of the National Highway System and created stop-and-go conditions on an additional 8,700 miles.
Figure 4-3. Peak-Period Congestion on the National Highway System: 2040
Assuming no changes in network capacity, increases in truck and passenger vehicle traffic are forecast to expand areas of recurring peak-period congestion to 34 percent of the National Highway System (NHS) in 2040, compared with 10 percent in 2011. This would slow traffic on 28,000 miles of the NHS and create stop-and-go conditions on an additional 46,000 miles.
Large numbers of trucks on congested highways substantially impede interstate commerce. Recurring congestion slows traffic on 5,800 miles and creates stop-and-go conditions on 4,500 miles of the National Highway System, which carries more than 8,500 trucks per day.
Assuming no change in network capacity, the number of NHS miles with recurring congestion and a large number of trucks is forecast to increase significantly between 2011 and 2040. On highways carrying more than 8,500 trucks per day, recurring congestion will slow traffic on close to 7,400 miles and create stop-and-go conditions on an additional 22,000 miles.
Table 4-7. Average Time for Trucks to Travel One Mile at Select U.S.-Canada Border Crossings: 2014
Border crossings are potential bottlenecks in the freight transportation network. The Federal Highway Administration monitors truck crossing times at 15 U.S.-Canada border crossings. At all but two borders, transit times were longer for inbound U.S. traffic than for travel to Canada.
Table 4-8. Average Truck Transit Times at Select U.S.-Mexico Border Crossings: 2014
The U.S. Department of Transportation in partnership with the Texas Department of Transportation also measures transit times from Mexico to the Unites States at the Bridge of the Americas and the Pharr-Reynosa International Bridge. The data are collected using radio frequency identification technology installed at the start of the crossing (typically the end of the queue) and at the vehicle safety inspection station exit (the end of the crossing trip). Vehicle identification information is anonymously collected and time-stamped at each reader station, and travel time is calculated between the reader stations.