Traffic Density provides an indication of the level of
service being provided to the road users. Hence, there is a need to
study the traffic flow characteristics with specific reference to
density in detail. When the length and speed of the vehicles in a
traffic stream vary significantly, the concept of occupancy, rather
than density, is more appropriate to describe traffic concentration.
When the concept of occupancy is applied to heterogeneous traffic
condition, it is necessary to consider the area of the road space and
the area of the vehicles as the bases. Hence, a new concept named,
'area-occupancy' is proposed here. It has been found that the
estimated area-occupancy gives consistent values irrespective of
change in traffic composition.
[1] B. D. Greenshields, "The Density Factor in Traffic Flow," Traffic
Engineering, Vol. 30, No. 6, 1960, pp. 26-28 and 30.
[2] P. Athol, "Interdependence of Certain Operational Characteristics within
a Moving Traffic Stream," Highway Research Record, No. 72, HRB,
National Research Council, Washington, D.C., 1965, pp. 58-87.
[3] F. L. Hall, "The Relationship between Occupancy and Density,"
Transportation Forum, 1986, pp. 46-52.
[4] F. L. Hall, and B. N. Persaud, "Evaluation of Speed Estimated made
with Single-Detector Data from Freeway Traffic Management Systems,"
Transportation Research Record, No. 1232, Transportation Research
Board of the National Academies, D.C., 1989, pp. 9-16.
[5] J. H. Banks, "Another Look at a Priori Relationships among Traffic
Flow Characteristics," Transportation Research Record, No. 1510,
Transportation Research Board of the National Academies, D.C., 1995,
pp. 1-10.
[6] M. J. Cassidy, and B. Coifman, "Relation among Average Speed, Flow,
and Density and Analogous Relation between Density and Occupancy,"
Transportation Research Record, No. 1591, Transportation Research
Board of the National Academies, D.C., 1997, pp. 1-6.
[7] Y. Kim, and F. L. Hall, "Relationships between Occupancy and Density
Reflecting Average Vehicle Lengths," Transportation Research Record,
No. 1883, Transportation Research Board of the National Academies,
D.C., 2004, pp. 85-93.
[8] F. B. Lin, C. W. Su, and H. H. Huang, "Uniform Criteria for Level of
Service analysis of Freeways," Journal of Transportation Engineering,
ASCE, Vol. 122, No. 2, 1996, pp. 123-130.
[9] A. D. May, "Traffic Flow Fundamentals," Prentice-Hall, Inc.,
Englewood Cliffs, New Jersey, 1990.
[10] Revised Monograph on Traffic Flow Theory: A State-of-the-Art Report.
Transportation Research Board, National Research Council, Washington
D.C., 1997. Available: http://www.tfhrc.gov/its/tft/tft.htm.
[11] V. T. Arasan, and R. Z. Kozhy, "Methodology for Modeling Highly
Heterogeneous Traffic Flow," Journal of Transportation Engineering,
ASCE, Vol-131, No. 7, 2005, pp. 544-551.
[12] V. T. Arasan, and K. Krishnamurthy, "Effect of Traffic Volume on PCU
of Vehicles under Heterogeneous Traffic Conditions," Road &
Transport Research Journal, ARRB, Vol-17, No. 1, 2008, pp. 32-49.
[1] B. D. Greenshields, "The Density Factor in Traffic Flow," Traffic
Engineering, Vol. 30, No. 6, 1960, pp. 26-28 and 30.
[2] P. Athol, "Interdependence of Certain Operational Characteristics within
a Moving Traffic Stream," Highway Research Record, No. 72, HRB,
National Research Council, Washington, D.C., 1965, pp. 58-87.
[3] F. L. Hall, "The Relationship between Occupancy and Density,"
Transportation Forum, 1986, pp. 46-52.
[4] F. L. Hall, and B. N. Persaud, "Evaluation of Speed Estimated made
with Single-Detector Data from Freeway Traffic Management Systems,"
Transportation Research Record, No. 1232, Transportation Research
Board of the National Academies, D.C., 1989, pp. 9-16.
[5] J. H. Banks, "Another Look at a Priori Relationships among Traffic
Flow Characteristics," Transportation Research Record, No. 1510,
Transportation Research Board of the National Academies, D.C., 1995,
pp. 1-10.
[6] M. J. Cassidy, and B. Coifman, "Relation among Average Speed, Flow,
and Density and Analogous Relation between Density and Occupancy,"
Transportation Research Record, No. 1591, Transportation Research
Board of the National Academies, D.C., 1997, pp. 1-6.
[7] Y. Kim, and F. L. Hall, "Relationships between Occupancy and Density
Reflecting Average Vehicle Lengths," Transportation Research Record,
No. 1883, Transportation Research Board of the National Academies,
D.C., 2004, pp. 85-93.
[8] F. B. Lin, C. W. Su, and H. H. Huang, "Uniform Criteria for Level of
Service analysis of Freeways," Journal of Transportation Engineering,
ASCE, Vol. 122, No. 2, 1996, pp. 123-130.
[9] A. D. May, "Traffic Flow Fundamentals," Prentice-Hall, Inc.,
Englewood Cliffs, New Jersey, 1990.
[10] Revised Monograph on Traffic Flow Theory: A State-of-the-Art Report.
Transportation Research Board, National Research Council, Washington
D.C., 1997. Available: http://www.tfhrc.gov/its/tft/tft.htm.
[11] V. T. Arasan, and R. Z. Kozhy, "Methodology for Modeling Highly
Heterogeneous Traffic Flow," Journal of Transportation Engineering,
ASCE, Vol-131, No. 7, 2005, pp. 544-551.
[12] V. T. Arasan, and K. Krishnamurthy, "Effect of Traffic Volume on PCU
of Vehicles under Heterogeneous Traffic Conditions," Road &
Transport Research Journal, ARRB, Vol-17, No. 1, 2008, pp. 32-49.
@article{"International Journal of Architectural, Civil and Construction Sciences:57519", author = "V. Thamizh Arasan and G. Dhivya", title = "Measuring Heterogeneous Traffic Density", abstract = "Traffic Density provides an indication of the level of
service being provided to the road users. Hence, there is a need to
study the traffic flow characteristics with specific reference to
density in detail. When the length and speed of the vehicles in a
traffic stream vary significantly, the concept of occupancy, rather
than density, is more appropriate to describe traffic concentration.
When the concept of occupancy is applied to heterogeneous traffic
condition, it is necessary to consider the area of the road space and
the area of the vehicles as the bases. Hence, a new concept named,
'area-occupancy' is proposed here. It has been found that the
estimated area-occupancy gives consistent values irrespective of
change in traffic composition.", keywords = "Density Measurement, Heterogeneity, Occupancy,Traffic Flow.", volume = "2", number = "10", pages = "244-5", }