Design Considerations for Combined Highway Alignments
Publication: Journal of Transportation Engineering
Volume 123, Issue 1
Abstract
According to current highway design standards, horizontal and vertical alignments are treated separately in two-dimensional (2D) projections. In this paper, a model developed by the writers is used to study the effects of considering three-dimensional (3D) alignment on design requirements for sight distance. First, the paper examines the required minimum radius of a horizontal curve combined with a crest or sag vertical curve in a cut section. Also, the required minimum length of a crest vertical curve combined with a horizontal curve in a fill section is studied. The results show that the 3D design requirements may differ significantly from those in separate 2D projections. Depending on the vertical alignment and on the cut side-slope, 2D design may underestimate or overestimate the required radius. In fill sections, the 2D alignment overestimates the required length of the crest vertical curve when combined with long horizontal curves. In summary, the 2D alignment can compromise both safety and economics of highways. As a result, it is concluded that 3D-based design standards should be developed and used in highway geometric design.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Easa, S. M.(1994). “Design considerations for highway reverse curves.”Transp. Res. Rec., 1445, 1–11.
2.
Easa, S. M., Abd El Halim, A. O., and Hassan, Y.(1996). “Sight distance evaluation on complex highway vertical alignments.”Can. J. Civ. Engrg., 23(3), 577–586.
3.
Geissler, E. H.(1968). “A three-dimensional approach to highway alignment design.”Hwy. Res. Rec., 232, 17–28.
4.
Hassan, Y., Easa, S. M., and Abd El Halim, A. O. (1995a). “New development for establishing no-passing zones on two-lane highways due to vertical alignments.”Proc., 1995 Annu. Conf. of Can. Soc. for Civ. Engrg., CSCE, Montreal, Quebec, IV, 205–214.
5.
Hassan, Y., Easa, S. M., and Abd El Halim, A. O.(1995b). “Sight distance on horizontal alignments with continuous lateral obstructions.”Transp. Res. Rec., 1500, 31–42.
6.
Hassan, Y., Easa, S. M., and Abd El Halim, A. O. (1995c). “User's guide of MARKC: a program for establishing no-passing zones on two-lane highways due to combined horizontal and vertical alignments.”Res. Rep. LU-TRC-RR-95-1, Transp. Res. Ctr., Lakehead Univ., Thunder Bay, Ontario, Canada.
7.
Hassan, Y., Easa, S. M., and Abd El Halim, A. O.(1996a). “Analytical model for sight distance analysis on 3-D highway alignments.”Transp. Res. Rec., 1523, 1–10.
8.
Hassan, Y., Easa, S. M., and Abd El Halim, A. O. (1996b). “Computer model for establishing no-passing zones on 3-D highway alignments.”Proc., 1st Transp. Spec. Conf., S. Easa, ed., Can. Soc. for Civ. Engrg., Montreal, Quebec, IIIb, 411–422.
9.
Krammes, R. A., and Garnham, M. A. (1995). “Review of alignment design policies worldwide.”Symp. on Hwy. Geometric Des. Practices, Transp. Res. Board, Washington, D.C.
10.
Mannering, F. L., and Kilareski, W. P. (1990). Principles of highway engineering and traffic analysis. John Wiley & Sons, Inc., New York, N.Y.
11.
Manual of geometric design standards for Canadian roads. (1986). Transp. Assn. of Canada (TAC), Ottawa, Canada.
12.
Park, R. A., Rowan, N. J., and Walton, N. E. (1968). “A computer technique for perspective plotting of roadways.”Hwy. Res. Rec., 232, 29–45.
13.
A policy on geometric design of highways and streets. (1994). Am. Assn. of State Hwy. and Transp. Officials (AASHTO), Washington, D.C.
14.
Sanchez, E.(1994). “A 3-dimensional analysis of sight distance on interchange connectors.”Transp. Res. Rec., 1445, 101–108.
15.
Smith, B. L., and Lamm, R.(1994). “Coordination of horizontal and vertical alignment with regard to highway esthetics.”Trans. Res. Rec., 1445, 73–85.
Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 123 • Issue 1 • January 1997
Pages: 60 - 68
Copyright
Copyright © 1997 American Society of Civil Engineers.
History
Published online: Jan 1, 1997
Published in print: Jan 1997
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.