New Insights into Freeway Capacity at Work Zones: Empirical Case Study

Abstract

A construction project in Ontario, Canada, provided the opportunity to use field data to investigate freeway capacity at long-term lane closures due to rehabilitation work. Data from two lane closures at the same construction site (eastbound and westbound) were examined. The site is located on the Gardiner Expressway in the southern part of downtown Toronto. Data were collected during 4 days, totaling around 53 h of congested traffic operations. Results showed significant variation in freeway capacity in the work zones. Despite this variation, average capacity values are reasonably close to the corresponding values provided in the Highway Capacity Manual. Four intervening variables were investigated; all exhibited significant but different effects on freeway work-zone capacity. These variables included temporal variation (which is thought to relate to driver characteristics), grade, day of week, and weather conditions. The results confirmed the pressing need for more extensive field data that will allow better identification of the effect of various control variables on work-zone capacity.

Get full access to this article

View all access options for this article.

References

Special Report 209: Highway Capacity Manual (1997 update). TRB, National Research Council, Washington, D.C., 1998.

Lewis

R. M.

Work-Zone Traffic Control Concepts and Terminology. In Transportation Research Record 1230, TRB, National Research Council, Washington, D.C., 1989, pp. 1–11.

Dudek

C. L.

, and Ullman

G. L.

. Traffic Control for Short-Duration Maintenance Operations on Four-Lane Divided Highways. In Transportation Research Record 1230, TRB, National Research Council, Washington, D.C., 1989, pp. 12–19.

Hall

J. W.

, and Lorenz

V. M.

. Characteristics of Construction-Zone Accidents. In Transportation Research Record 1230, TRB, National Research Council, Washington, D.C., 1989, pp. 20–27.

Krammes

R. A.

, and Ullman

G. L.

. Synthesis of Traffic Management Strategies for Urban Freeway Reconstruction Projects. In Transportation Research Record 1232, TRB, National Research Council, Washington, D.C., 1989, pp. 40–48.

Levine

S. Z.

, and Kabat

R. J.

. Planning and Operation of Urban Highway Work Zones. In Transportation Research Record 979, TRB, National Research Council, Washington, D.C., 1984, pp. 1–6.

Pal

, and Sinha

K. C.

. Analysis of Crash Rates at Interstate Work Zones in Indiana. In Transportation Research Record 1529, TRB, National Research Council, Washington, D.C., 1996, pp. 43–53.

Pain

R. F.

, McGee

H. W.

, and Knapp

B. G.

. NCHRP Report 236: Evaluation of Traffic Controls for Highway Work Zones. TRB, National Research Council, Washington, D.C., 1981.

Wang

, Hughes

W. E.

, Council

F. M.

, and Paniati

J. F.

. Investigation of Highway Work Zone Crashes: What We Know and What We Don’t Know. In Transportation Research Record 1529, TRB, National Research Council, Washington, D.C., 1996, pp. 54–62.

10.

Kermode

R. H.

, and Myyra

W. A.

. Freeway Lane Closures. Traffic Engineering, Vol. 40, No. 5, Feb. 1970.

11.

Dixon

K. K.

, Hummer

J. E.

, and Lorscheider

A. R.

. Capacity for North Carolina Freeway Work Zones. In Transportation Research Record 1529, TRB, National Research Council, Washington, D.C., 1996, pp. 27–34.

12.

Krammes

R. A.

, and Lopez

G. O.

. Updated Capacity Values for Short- Term Freeway Work Zone Lane Closures. In Transportation Research Record 1442, TRB, National Research Council, Washington, D.C., 1994, pp. 49–56.

13.

Dudek

C. L.

, Richards

S. H.

, and Wunderlich

R. C.

. Handling Traffic in Work Zones. Report FHWA/TX-86-57+292-6F. Texas Transportation Institution College Station, 1985.

14.

Persaud

B. N.

, and Hurdle

V. F.

. Freeway Capacity: Definition and Measurement Issues. Proc., International Symposium on Freeway Capacity and Level of Service, Karlsruhe, Germany, 1991.

15.

Ringert

, and Urbanik

II . Study of Freeway Bottlenecks in Texas. In Transportation Research Record 1398, TRB, National Research Council, Washington, D.C., 1993, pp. 31–41.

16.

Agyemang-Duah

, and Hall

. Some Issues Regarding the Numerical Value of Freeway Capacity. Proc., International Symposium on Freeway Capacity and Level of Service, Karlsruhe, Germany, 1991.

17.

Banks

J. H.

The Two-Capacity Phenomenon: Some Theoretical Issues. In Transportation Research Record 1320, TRB, National Research Council, Washington, D.C., 1991, pp. 234–241.

18.

Banks

J. H.

Two-Capacity Phenomenon at Freeway Bottlenecks: A Basis for Ramp Metering? In Transportation Research Record 1320, TRB, National Research Council, Washington, D.C., 1991, pp. 83–90.

19.

Hall

F. L.

, and Agyemang-Duah

. Freeway Capacity Drop and the Definition of Capacity. In Transportation Research Record 1320, TRB, National Research Council, Washington, D.C., 1991, pp. 91–98.

20.

Hall

F. L.

, Hurdle

V. F.

, and Banks

J. H.

. Synthesis of Recent Work on the Nature of Speed-Flow and Flow-Occupancy (or Density) Relationships on Freeways. In Transportation Research Record 1365, TRB, National Research Council, Washington, D.C., 1992, pp. 12–18.

21.

Yagar

, and Hui

. Systemwide Analysis of Freeway Improvements. In Transportation Research Record 1554, TRB, National Research Council, Washington, D.C., 1996, pp. 172–183.

22.

Morgan

, and Griego

O. V.

. Easy Use and Interpretation of SPSS for Windows: Answering Research Questions with Statistics. Laurence Erlbaum Associates, 1998.