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CHAPTER 1
Introduction
In many urban areas throughout the United States, there is · The HCM lists nine conditions (p. 15-1) not accounted for
a desire to evaluate transportation services of roadways from in the current urban streets methodology:
a multimodal perspective. Improvements to non-automobile 1. Presence or lack of on-street parking;
modes are often emphasized to achieve community goals 2. Driveway density or access control;
such as "Smart Growth" and curbing urban sprawl. The 3. Lane additions leading up to or lane drops leading away
Transportation Equity Act for the 21st Century (TEA-21) and from intersections;
its predecessor, the Intermodal Surface Transportation Effi- 4. The impacts of grades between intersections;
ciency Act of 1991 (ISTEA), call for mainstreaming transit, 5. Any capacity constraints between intersections (such as
pedestrian, and bicycle projects into the planning, design, and a narrow bridge);
operation of the U.S. transportation system. In addition to 6. Mid-block medians and two-way left turn lanes;
measuring the levels of service for automobile users, measur- 7. Turning movements that exceed 20 percent of the total
ing the levels of service for transit, pedestrian, and bicycle volume on the street;
users along U.S. roadways is also desired. 8. Queues at one intersection backing up to and interfer-
ing with the operation of an upstream intersection; and
9. Cross-street congestion blocking through traffic.
1.1 Research Objective and Scope
The objective of NCHRP Project 3-70 was to develop and These limitations were not necessarily to be accepted in
test a framework and enhanced methods for determining lev- this project.
els of service for automobile, transit, bicycle, and pedestrian
modes on urban streets, paying particular respect to the in- · Although this project was to address automobile LOS, re-
teraction among the modes. visions in operational techniques (e.g., calculation of aver-
The scope of the project was as follows: age travel speed, mid-block running times, and control
delay) for the automobile mode were not a significant part
· Urban streets were defined as arterials and major collectors. of this project.
· This research project was to address all vehicular and
pedestrian movements along urban streets, including turn-
1.2 The Research Plan
ing movements and pedestrian movements across urban
streets. The research plan consisted of the following tasks:
· Transit (i.e., bus and rail) was initially defined as at-grade,
scheduled, fixed-route services that operated within the 0. Development of Amplified Work Plan
roadway right-of-way. Other forms of transit services were 1. LOS Framework Revisions
allowed be addressed subsequently. 2. Data Collection
· The analysis techniques were not necessarily to be re- 3. Develop LOS Models
stricted to 1-hour or 15-minute analysis time frames (tran- 4. Interim Report
sit or pedestrian "micro-peaks"). 5. HCM Chapter
· Safety and economic aspects were to be included only and 6. HCM Software
insofar as they influenced the perceptions of LOS. 7. HCM Sample Problems
