Details:

Creators:
Fitzpatrick, Kay
Corporate Contributors:
Texas Transportation Institute
Subject/TRT Terms:
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Computer Aided Design Computer Models Design Consistency, Interactive Highway Safety Design Model (IHSDM) Design Speed Driver Workload Geometric Design Highway Design Highway Geometric Design Consistency Evaluation Methods Highway Planning Highway Safety Rural Highways Speed Distribution Speed Limits Speed Prediction Speed Profile Two Lane Highways
Publication/ Report Number:
FHWA-RD-99-173
Resource Type:
Research Paper
TRIS Online Accession Number:
00819634
Corporate Publisher:
United States. Federal Highway Administration
NTL Classification:
NTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATION;NTL-HIGHWAY/ROAD TRANSPORTATION-Design;NTL-SAFETY AND SECURITY-Human Factors;NTL-SAFETY AND SECURITY-Speed Limits;NTL-SAFETY AND SECURITY-Highway Safety;NTL-OPERATIONS AND TRAFFIC CONTROLS-Traffic Flow;
Abstract:
Design consistency refers to the conformance of a highway's geometry with driver expectancy. Techniques to evaluate the consistency of a design documented within this report include speed-profile model, alignment indices, speed distribution measures, and driver workload. The use of operating speed as a consistency tool requires the ability to accurately predict speeds as a function of the roadway geometry. In this research project, several efforts were undertaken to predict operating speed for different conditions such as on horizontal, vertical, and combined curves; on tangent sections using alignment indices; on grades using the TWOPAS model; and prior to or after a horizontal curve. The findings from the different efforts were incorporated into a speed-profile model. Alignment indices are quantitative measures of the general character of a roadway segment's alignment. These potential indicators may identify a geometric inconsistency when there is a large increase in the magnitude of the alignment indices for a successive roadway segment or feature or when a high rate of change occurs over some roadway length. Speed distribution measures investigated included variance, standard deviation, coefficient of variation, and coefficient of skewness. Driver workload is a measure of the information processing demands imposed by roadway geometry on a driver. Principal investigators were Kay Fitzpatrick and Raymond A. Krammes with with contributions by (in alphabetical order): Ingrid B. Anderson, Karin M. Bauer, Jon M. Collins, Lily Elefteriadou, Paul Green, Douglas W. Harwood, Nelson Irizarry, Rodger Koppa, John McFadden, Kelly D. Parma, Karl Passetti, Brian Poggioli, Omer Tsimhoni, and Mark D. Wooldridge. Work performed under contract DTFH61-95-R-00084. 9 Figures, 5 tables, 13 references. 384k, 29p.
Format:
PDF
Collection(s):
Federal Highway Administration US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:fb24121b7d9635bbe682a09764a56b5b19b791e925d3ea4bc7c64a224bc3bc94
Download URL:
https://rosap.ntl.bts.gov/view/dot/14743/dot_14743_DS1.pdf
File Type:

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