Conditions and Performance Chapter Listing

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Introduction

Summary

Highway and Bridge System and Use Characteristics

Transit System Characteristics

Use Characteristics

This section describes highway infrastructure use. Highway use is defined by VMT. Total highway VMT grew to 2.6 trillion in 1997. While Exhibit 2-11 shows increases for both urban and rural systems, perhaps the most interesting change is the growth in VMT on rural highways. Rural highway VMT climbed from 937 billion in 1995 to over 1.0 trillion in 1997, a 7.2 percent increase. During this time, urban highway vehicle-miles increased by 4.1 percent, from 1.50 trillion to about 1.56 trillion.

Exhibit 2-11. Highway Vehicle (VMT) and Passenger Miles of Travel (PMT), 1987-1997

Exhibits 2-12 and 2-13 describe highway travel by functional classification and vehicle type, expanding on the information in Exhibit 2-11. In these exhibits there are three types of vehicles. Passenger vehicles (PV) include buses and 2-axle, 4-tire vehicles; single unit trucks (SU) have 6 or more tires; and combination trucks (Combo) include trailers and semi-trailers.

Exhibit 2-12. Highway Travel by Vehicle Type, 1987-1997

Exhibit 2-13. Highway Travel by System and Vehicle Type, 1987-1997

As Exhibits 2-12 and 2-13 show, travel grew the fastest on rural and urban interstates, particularly among combination trucks. For example, the average annual growth rate between 1987 and 1997 was 4.4 percent for combination trucks on rural interstates and 3.9 percent on urban interstates. Overall, passenger vehicle travel grew by an average of 2.8 percent annually between 1987 and 1997. Single unit truck travel grew by about 3.4 percent each year, and combination truck travel increased by an average of 3.8 percent annually.