DEVELOPMENT OF A SYSTEM FOR TWO-LANE HIHGWAY CAPACITY ASSESSMENT
Main researcher
: RAKO, VICKO (40175) Assistants
HUNJET, DUBRAVKO (62914)
SZIROVICZA, LAJOS (70586)
ROŽIĆ, PLANKO (157642)
Type of research: basic Duration from: 01/01/91. to 12/31/95. Papers on project (total): 18
Papers on project quoted in Current Contents: 1
Institution name: Građevinski fakultet, Zagreb (82) Department/Institute: Department of Transportation Engineering Address: Kačićeva 26, 41000 Zagreb City: 10000 - Zagreb, Croatia
Communication
Fax: 385 (01) 416-621
Phone: 385 (01) 4561-222/356
Summary: Movement of vehicles within the test section is researched
by a newly established method. Measurement of traffic flow is carried
out on the highway section under ideal conditions with respect to roadway,
traffic, and environment, respectively. Since every single vehicle is
recorded according to type of vehicle, position of vehicle within a
traffic flow, speed of vehicle, headway, and spacing, results of
measurement enable us to establish correlation between these parameters
from the aspect of highway capacity and traffic safety. The influence of
both the time interval of measurement and division of traffic flow on the
level of the highway capacity is established by iterative procedure. By
changing the headway, which serves as a criterion for the defining of
car-following within the platoon, the influence of that criterion on the
rate of flow, and the highway capacity is established. The main, already
known, traffic stream models are tested and new models are developed on
the basis of the data evaluation comprising the relationships among the
fundamental traffic stream variables. On the basis of the newly developed
algorithms, and softwares and by integretion of the numerical and graphic
analyses of the traffic, both the traffic within the test sections and the
highway capacities are presented graphicaly. It has been assessed that the
ideal capacity of a single traffic lane is 2,200 pcphpl while the ideal
capacity of a two-lane two-way rural highway is 4,000 pcph.
Keywords: Highway capacity, level of service, traffic flow, fundamental traffic stream variables, measurements, traffic stream models, two-lane highway, platoon.
Research goals: This research is based on measurements and results
of research ofthe traffic flow parameters on, and the capacity of, the
two-lanehighways. Ideal flow which consists of passenger cars only, does
not exist in the field. Consequently, up to now highway capacity is based
on the hypothetical relationships within the traffic flow, i.e.,the
highway capacity is assessed on the basis of correction of ideal
conditions through the application of several adjustment factors.
Divisions of traffic flow on a time basis that have been applied up to now
used to include all fluctuation within the traffic flow, and did not
provide the real basis for a highway capacity assessment. The combinations
of traffic flow condition are defined by divisions of traffic flow on a
functional basis, as well as from the aspect of car-following, thereby
providing areal basis for highway capacity assessment. The purpose of this
Project is to research the influence of each individual parameter on
determination of the combinations of traffic flow condition and,
indirectly, on highway capacity and the levels of service. A further aim
of the Project is to provide a theoretical contribution to the study of
regularity of vehicles moving within a traffic flow and to ensure the
basis for generating the models of fundamental traffic stream variables on
two-lane highway, as well as to define the combinations of traffic flow
condition in real conditions, which is a prerequisite for forming platoons
with mixed vehicles, and platoons with passenger cars only. Other information about the project.