00226766

Component

http://onlinepubs.trb.org...s/hrr/1973/432/432-002.pdf

AN ANALYTICAL METHOD IS PROPOSED FOR THE DESIGN OF GUIDEWAY ELEMENTS SUBJECT TO JERK AND ACCELERATION LIMITS. THE METHOD GENERALIZES THE LIMITS ON LATERAL JERK AND ACCELERATION FAMILIAR IN HIGHWAY DESIGN TO THE FORE-AFT AND VERTICAL MODES. IT IS PROPOSED THAT, UNDER COMBINATIONS OF THESE MODES, THE MAGNITUDES OF THE JERK AND EFFECTIVE ACCELERATION VECTORS MUST BE LIMITED. EQUATIONS DESCRIBING THE LEVEL OF DISCOMFORT ARE DERIVED FOR BOTH CONSTANT AND VARIABLE-SPEED MOTION ALONG HORIZONTAL AND VERTICAL CURVES. THE EQUATIONS EXPLICITLY INCLUDE THE EFFECT OF SUPERELEVATION. A FOUR-SPIRAL SWITCH FOR USE IN A PERSONALIZED RAPID TRANSIT SYSTEM IS ANALYZED IN DETAIL. IT IS FOUND THAT A LENGTH REDUCTION OF MORE THAN 25 PERCENT IS POSSIBLE BY USING SUPERELEVATION. A RIGHT ANGLE TURN COMPOSED OF TWO SPIRALS AND A CIRCULAR ARC IS DETAILED. IT IS FOUND THAT THE USE OF SUPERELEVATION CAN REDUCE THE MAGNITUDES OF THE EFFECTIVE JERK AND ACCELERATION VECTORS BY MORE THAN 50 PERCENT. FINALLY, A FOUR-SPIRAL GRADE CHANGE IS DETAILED. DISCOMFORT IS INVESTIGATED AND COMPARED FOR CONSTANT SPEED AND ZERO FORE-AFT THRUST MOTION. IT IS SHOWN THAT THE USUAL ANALYTICAL APPROACH THAT INCLUDES ONLY THE CENTRIPETAL COMPONENT OF ACCELERATION AND JERK CAN LEAD TO CONSIDERABLE ERROR IN PREDICTING DISCOMFORT.

Sponsored by Commitee on Operational Effects of Geometrics. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.

01408179

pp 12-24

1973

Highway Research Record

52nd Annual Meeting of the Highway Research Board

0309021626

Digital/other

Appendices (1) ; Figures (8) ; References (12) ; Tables (1)

Acceleration (Mechanics); Comfort; Design; Equations; Guideways; Jerk control; Personal rapid transit; Superelevation

Design; Highways; Operations and Traffic Management; Terminals and Facilities

TRIS, TRB

Dec 22 1973 12:00AM

• AN ANALYSIS OF THE SHIRLEY HIGHWAY EXPRESS-BUS-ON-FREEWAY DEMONSTRATION PROJECT (ABRIDGMENT)
• COST-EFFECTIVENESS EVALUATION OF FREEWAY DESIGN ALTERNATIVES
• ELEMENTS OF MEDIAN DESIGN IN RELATION TO ACCIDENT OCCURRENCE
• EVALUATION OF FREEWAY TRAFFIC FLOW AT RAMPS, COLLECTOR ROADS, AND LANE DROPS
• LATERAL VEHICLE PLACEMENT AND STEERING WHEEL REVERSALS ON A SIMULATED BRIDGE OF VARIABLE WIDTH
• SOME CASE STUDIES OF HIGHWAY BRIDGES INVOLVED IN ACCIDENTS
• TRADE-OFF ANALYSES IN MAJOR INTERCHANGE DESIGN