00983185

Component

https://doi.org/10.3141/1881-03

http://scholar.google.com...acek&publication_year=2004

In Switzerland, a speed diagram is used to check the consistency of the alignment of a section of highway. The sequence of alignment elements is subject to maximum permitted differences for the design speed, and the highest design speed is coupled to the general speed limit applicable to the category of highway in question. After a significant reduction in the speed limit for rural highways [100 to 80 km/h (62 to 50 mph)], the application of this model as a control instrument in practice has become problematic. Consideration is being given to an alternative procedure, such as specifying the permitted radii sequence. The analysis deals principally with the changes in speed behavior compared with previous surveys from the period when a higher speed limit was in place. The main focus of this study was the relationship between curve radius and running speed; the influence of other design elements in curves and speed behavior on curves on rural highways were also investigated. The alignment model in Swiss geometric design standards is described. On the basis of the new findings, the problems of the Swiss alignment model and the implications for existing design standards were analyzed.

This paper appears in Transportation Research Record No. 1881, Geometric Design and the Effects on Traffic Operations 2004.

00983182

English

p. 19-26

2004

Transportation Research Record

0309094771

Figures (13) ; References (8)

Alignment; Design speed; Design standards; Geometric design; Highway curves; Radius; Running speed; Rural highways; Speed limits; Traffic speed

Switzerland

Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure

TRIS, TRB, ATRI

Dec 2 2004 12:00AM

• BASIS OF THE SWISS DESIGN STANDARD FOR ROUNDABOUTS
• DESIGN AND OPERATIONAL PERFORMANCE OF CROSSOVER DISPLACED LEFT-TURN INTERSECTIONS
• DETERMINING CRITICAL LENGTH OF GRADE FOR GEOMETRIC DESIGN OF VERTICAL ALIGNMENTS
• DEVELOPMENT OF THE DISPLACED RIGHT-TURN INTERSECTION
• FUZZY MODEL FOR SAFETY EVALUATION PROCESS OF NEW AND OLD ROADS
• GEOMETRIC MODELS TO CALCULATE INTERSECTION SIGHT DISTANCE FOR UNPROTECTED LEFT-TURN TRAFFIC
• HIGHWAY DESIGN CONSISTENCY: REFINING THE STATE OF KNOWLEDGE AND PRACTICE
• LENGTHS OF DOUBLE OR DUAL LEFT-TURN LANES