scope:

SCOPE OF OPERATIONS

The Vehicle Operation Survey (VOS) was conducted in two phases. Phase I efforts were divided among the following tasks:

o Design, fabrication, installation, and checkout of digital data acquisition systems

o Construction of four representative driving survey routes in Los Angeles

o Training of personnel and data collection on the Los Angeles routes

o Writing of computer programs and initial processing of Los Angeles data.

Phase II activities were guided by the experience obtained during Phase I. Phase II tasks were:

o Design and construction of driving survey routes for Houston, Cincinnati, Chicago, and New York City

o Collection of data in the above four cities

o Modification of computer programs written in Phase I to optimize processing efficiency and output of useful information

o Processing of data for all five cities (including reprocessing of Los Angeles data with revised programs)

o Design, and evaluation of a road route in Ann Arbor, Michigan, which was intended to typify the five-city composite results

o Evaluation of vehicle operating patterns on the LA-4 road route for comparison with urban Los Angeles results

o Analysis of data and final report.

Throughout the duration of the data acquisition operations, two primary survey vehicles (plus one back-up vehicle) were used for collecting data in each city. The data represent a total of 22,465 miles of freeway, arterial, and capillary roads surveyed during the spring of 1971. Data collection consisted of operating (nominally) from 6:00 am to 10:00 pm for 7 consecutive days in each major urban area. Nearly 31 million pieces of information were recorded on 1/2 inch magnetic tape for subsequent computer processing.

The initial program schedule included the surveying of vehicle operating patterns in the Minneapolis-St. Paul area. This task was dropped, however, in favor of conducting an evaluation of the LA-4 road route, not originally included in the project plans.

No data collected during the course of program were considered unusable due to extreme weather effects on traffic flow. Rain was observed in all cities except Chicago; however, neither the rate nor extent of Che precipitation was sufficient to create atypical driving patterns. The digital data acquisition systems performed with very few instances of malfunction. Occasional problems with electro-mechanical components were easily remedied.

The data processing programs yielded various descriptive measures of driving patterns in tabular, matrix, and graphical format. No single measure of vehicle operating patterns can be considered as adequate for representing the total pattern for a city. Therefore, a set of evaluation measures was used Co analyze and compare data for each city with the other cities and with the composite.