Some of the most severe traffic and transportation problems occur in, and around the central business districts of our urban areas. The results of these problems include delays, congestion, accidents, confusion, and discomfort, combined with a variety of other equally undesireable effects. In the process of obtaining and designing solution devices and developing techniques to plan for, and respond to, these problems and situations, it is necessary to obtain and analyze several types of data.

An application of time-lapse photography as a tool for solving highway engineering problems can be seen in this study to evaluate the effects of a new diagrammatic sign. The principal variable for determining the effect of the sign on motorists was vehicular erratic maneuvers in a before and after study. Time-lapse photography provided an economical and accurate means of data acquisition.

Traffic volume studies are important to the United States Forest Service for basically the same reasons they are important to State Highway Departments and other Agencies. We desire to obtain data concerning the movement of vehicles and/ or persons on the transportation system.

A. General This is an interim report of a Federal-Aid Research Project entitled "D-4-108, Monitoring Field Installation of Impact Energy Attenuator by Video Tape . This project was approved by the FHWA on June 29, 1971. The report presents information gathered to date regarding the equipment and modifications necessary to conduct the study. The conclusion and recommendation will be presented in our final report which will be submitted at the completion of this project in December 1973.

The purpose of this paper is to describe not only the equipment used but also the varied applications of Time Lapse Photography in traffic surveillance. * Development in Time Lapse Photo-graphy with the Div. of Hwys. * Uses of Time Lapse Photography. * Equipment and Specifications. * Conclusions. It should be noted that in the field of Time Lapse Photography we are but struggling infants. This paper basically covers our original needs, how we went about solving our needs, and the equipment we are now using.

A variety of photographic instrument systems have been studied to determine an optimum technique for supplementing or replacing manual methods for obtaining map data for auto collision sites. These systems include (a) a single camera perspective-grid system (Ref. 1), (b) the elevating of an overhead camera on a truck mounted boom (Ref. 2), and (c) twin camera stereometric camera systems produced in Europe (Ref. 3). The European systems are factory produced and represent equipment fabricated to exacting standards capable of producing plotted data to prescribed standards. Such units are tripod mounted or designed to operate from an elevating post mount in a vehicle.

The use of time-lapse photography to study traffic behavior is well known to most traffic engineers. Inherent in its use, however, are at least two problems that have plagued engineers for many years: the high cost of equipment and the difficulty of photographing traffic on all approaches to an intersection with a single camera.

Increasing awareness of roadside hazards, primarily in the form of rigid fixed objects, has given rise to the development of sophisticated devices designed either to replace unsafe, outmoded, but essential roadway items, or to enhance the safety of existing difficult-to-replace items. Classed with the former group are such devices as breakaway light poles, weak-post guide railing and the New Jersey concrete median barrier, while various types of crash cushions, otherwise known as impact-attenuation devices, are referred to the latter group. Most promising among the crash cushions are the Rich system, consisting of a network of water filled rubber cells, and the Fitch system, which is made up of a number of sand-filled plastic barrels.

Photologging is the use of photography, with the intent that a sequential pictorial record will be maintained. The pictorial record will yield an image of an actual situation, which when displayed, can be visually analyzed. This particular use of photography is presently being applied to highways, showing the highway from the driver's eye level. Some typical uses of the highway photolog include: complete visual highway inventory, accident surveillance, roadside rest areas, visual obstructions, contours -- and just about an unlimited number of other useful applications.

Gentlemen: In the next 30 minutes I would like to give you a brief discussion on the system of Photologging now in use in the North Carolina State Highway Commission. In the discussion, I plan to briefly cover our equipment, something of the integrated system we have found useful, some of the problems we have encountered, and some of the uses made of the product.

The West Virginia Department of Highways is responsible for the maintenance and control of traffic on some 30,000 miles of public roads, including almost 6,000 miles of Expressway, Trunkline and Feeder highways. For the most part,'this highway system traverses rugged, constantly changing terrain in rural, lightly populated areas. Due to the vast amount of data required per mile of highway, we have for several years sought methods to automatically record road inventory data. In 1966 we first used a camera mounted inside a survey vehicle to record grade and curvature information from an instrument panel. No roadway photos were taken, only the data display on the instrument panel was filmed. The panel was aircraft surplus and included a ball-bank indicator, gyroscopic compass and altimeter, with an odometer added to provide mile post reference. The recording camera was 16mm and triggered manually one frame at a time. Instrument readings were normally recorded only at intersections and points of horizontal or vertical alignment change. Information from this first "photo-log" was then transferred to straight-line diagrams in the Central Office. Once the State was covered, perpetuation was accomplished by referring to construction plans and use of the camera technique was discontinued.

Photologging programs are now conducted by at least four provincial highways departments in Canada, British Columbia, New Brunswick, Ontario, and Quebec, in that order. Each of these departments have in turn moved into photologging by initially constructing their own equipment, and after assessing the tremendous potential of the technique in their applications, have moved on to purchase or consider commercial equipment designed and constructed to meet the exact and specific requirements of the experienced user. This paper deals with the development of photologging equipment and its use in Canada - at first by the Departments of Highways of British Columbia and New Brunswick - and the gradual involvement of B.C. Research and Techwest Enterprises Ltd. in taking over the continuous development and supply of equipment designed to match the rapidly expanding needs of highways' engineers as their own analytical requirements and field applications increase.

There are thirty-three proclaimed National Forests in fourteen states comprising the Southern Region of the U. S. Forest Service. The road system totals 14,426 miles, of which 417 miles are paved, 5,425 miles have soil or aggregate surfaces, and 8,584 miles have graded and drained surfaces. The terrain varies from mountainous North Carolina and East Tennessee to the flat lands of Florida, Louisiana, and Texas.

Having a detailed photographic record of each highway, its appurtenances, and its adjacent features, is advantageous for evolving maintenance programs, correcting defects, and eliminating hazards. The pictorial record, however, unless it can be used for determining position, spacing, and relevant dimensions wherever required is not fully effective. Techniques are presented for computing dimensions, using measurements made on the photographs taken singly and at a longitudinal spacing of known length along the highway, or at random, if necessary. Tests indicate position and dimension determined using the developed equations do not differ by more than 5% from actual values. Greater precision is feasible, if fiducial marks are provided and accurate positioning of the perspective center is readily obtainable.

Photologging is presently being used by the City of San Diego for the inventory of traffic control devices. Other uses being contemplated will be presented later in this paper.

In February of 1972, initial discus sions were carried on with Mr. Al Klahn, Assistant Engineer, for Placer County on doing a complete Photolog of all county maintained roads and highways. This consisted of 1000 one way miles, a total of 2000 miles of roads, in a county measuring approximately 80 miles from West to East and 22 miles North to South. Terrain ranged from flat farm land to densley forested mountains to the shores of Lake Tahoe. Road conditions varied from well paved streets to routes that were barely logging trails.

Placer County California has purchased a road encyclopedia describing one thousand roads averaging one mile in length. This one thousand miles of roadway averages 46 persons living on each mile, and one accident per year on each one-and-a-half miles of road.

Last November the filming of the Washington State Highway System was completed. Today the cost involved in developing the photo logging system and how the photofile is actually used will be discussed.

Ben Johnson wrote of Shakespeare that he had small Latin and less Greek."(Ref. 1) As one who has small cost-effectiveness experience and less photologging, I feel myself well qualified to talk about the cost-effectiveness of photologging.