Speed Factors on Low -Volume Roads for Horizontal Curves and Tangents

Gianluca Dell’Acqua, Francesca Russo


Many studies on driver speed behavior are found in the scientific literature today, and various researchers have addressed roadway alignment consistency for travel safety in context with current operating speeds. Experimental analysis was conducted on low-volume roads in Southern Italy without spiral transition curves between geometric tangent and circular elements on the horizontal alignment. All selected roads are located in areas with level terrain and vertical grades less than 6%. This study will illustrate a methodology, widely employed in the literature, to evaluate at each circular curve transition segment length, the applicable deceleration and acceleration rates. These results were then used to develop four equations for speed prediction models on tangents and curves. These regression equations were developed using a traditional Ordinary-least-squares method involving speed values not surveyed in transition zones. The goal of this research study is to plot continuous speed profiles to illustrate complete driver speed behavior on twolane rural roads and to individualize critical roadway sections to improve driver safety.


driver speed behavior; operating speed profile; roadway alignment consistency

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Dragčević, V.; Korlaet, Z.; Stančerić, I. 2008. Methods for Setting Road Vehicle Movement Trajectories, The Baltic Journal of Road and Bridge Engineering 3(2): 57‒64. doi:10.3846/1822-427X.2008.3.57-64

Figueroa-Medina, A.; Tarko, A. P. 2004. reconciling Speed Limits with Design Speeds. Final Report FHWA/IN/JTRP-2004/26, Purdue University ‒ Joint Transportation Research Program Project No. C-36-10G File No. 8-3-7 SPR- 2661, Purdue University West Lafayette, IN 47907.

Fitzpatrick, K.; Carlson, P.; Brewer, M.; Wooldridge, M.; Miaou, S. 2003. Design Speed, Operating Speed and Posted Speed Practices [cited 9 September, 2009]. Available from Internet: .

Fitzpatrick, K.; Collins, J. M. 2000. Speed Profile Model for Two-Lane Rural Highways, Transportation Research Record 1737: 42‒49. doi:10.3141/1737-06

Gibreel, G. M.; Easa, S. M.; Hassan, Y.; El-Dimeery, I. A. 1999. State of the Art of Highway Geometric Design Consistency, Journal of Transportation Engineering 125(4): 305‒313. doi:10.1061/(ASCE)0733947X(1999)125:4(305)

Lazda, Z.; Smirnovs, J. 2009. Evaluation of Road Traffic Safety Level in the State Main Road Network of Latvia, The Baltic Journal of Road and Bridge Engineering 4(4): 156‒160. doi:10.3846/1822-427X.2009.4.156-160

Ottesen, J. L.; Krammes., R. A. 2000. Speed Profile Model for Design-Consistency Evaluation Procedure in the United States, Transportation Research Record 1701: 76‒85. doi:10.3141/1701-10

Polus, A.; Fitzpatrick, K.; Fambro, D. B. 2000. Predicting Operating Speeds on Tangent Sections of Two-Lane Rural Highways, Transportation Research Record 1737: 50‒57. doi:10.3141/1737-07

Ratkevičiūtė, K.; Čygas, D.; Laurinavičius, A.; Mačiulis, A. 2007. Analysis and Evaluation of the Efficiency of Road Safety Measures Applied to Lithuanian Roads, The Baltic Journal of Road and Bridge Engineering 2(2): 81‒87.

DOI: 10.3846/bjrbe.2010.13


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