00452654

Component

http://onlinepubs.trb.org...trr/1985/1010/1010-009.pdf

https://scholar.google.co...stel&publication_year=1985

The city of Seattle has used more traffic circles than yield signs or stop signs to control four-way residential intersections in the past 10 years. The purpose of these traffic circles is to respond to above-average accident problems at neighborhood intersections without having to rely on the use of yield signs and stop signs. It was found in this study that both traffic circles and yield signs can reduce the number of intersection collisions by about 77 percent. Information reviewed for this study indicates that traffic circles can reduce midblock speeds by significant amounts. Locations with traffic circles reveal a variety of changes in volume after a circle has been placed. These changes are likely to be caused by other conditions in the neighborhood rather than by the circle. A total volume decrease of 2 percent (an insignificant change) was measured for 20 traffic locations. Similar data were not available for stop-sign and yield-sign locations. The cost for a traffic circle is much higher than for a yield sign, but if a city is willing to incur additional costs, circles can reduce the proliferation of traditional control devices, perhaps enhancing the effectiveness of signs elsewhere.

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. Publication of this paper sponsored by Committee on Traffic Control Devices.

01419893

pp 65-68

1985

Transportation Research Record

0309038227

Print

Figures (5) ; References (3)

Alternatives analysis; Before and after studies; Residential areas; Stop signs; Traffic circles; Traffic control; Traffic speed; Traffic volume; Yield signs

Seattle (Washington)

Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control

TRIS, TRB

Apr 30 1988 12:00AM

• ACTIVE ADVANCE WARNING SIGNS AT HIGH-SPEED SIGNALIZED INTERSECTIONS: A SURVEY OF PRACTICE (ABRIDGMENT)
• DETERMINATION OF MOTORIST VIOLATIONS AND PEDESTRIAN-RELATED COUNTERMEASURES RELATED TO RIGHT-TURN-ON-RED
• EFFECT OF SIGNAL TIMING ON TRAFFIC FLOW AND CRASHES AT SIGNALIZED INTERSECTIONS
• EFFECTIVENESS OF CONSTANT-WARNING-TIME VERSUS FIXED-DISTANCE WARNING SYSTEMS AT RAIL-HIGHWAY GRADE CROSSINGS (DISCUSSION AND CLOSURE)
• EFFECTIVENESS OF WILDLIFE WARNING REFLECTORS IN REDUCING DEER-VEHICLE ACCIDENTS IN WASHINGTON STATE
• EVALUATION AND IMPROVEMENT OF INDUCTIVE LOOP TRAFFIC DETECTORS
• EVALUATION OF CURVE DELINEATION SIGNS
• EVALUATION OF REFLECTORIZED SIGN SHEETING FOR NONILLUMINATED FREEWAY OVERHEAD GUIDE SIGNS
• FURTHER INVESTIGATION OF THE EFFECTIVENESS OF WARNING DEVICES AT RAIL-HIGHWAY GRADE CROSSINGS
• MONITORING AND EVALUATION OF HIGH-TYPE RAILROAD CROSSING SURFACES
• MULTIWAY STOP SIGN REMOVAL PROCEDURES (DISCUSSION AND CLOSURE)
• OPTIMAL TIMING SETTINGS AND DETECTOR LENGTHS OF PRESENCE MODE FULL-ACTUATED CONTROL
• PREFERENTIAL CONTROL WARRANTS OF LIGHT RAIL TRANSIT MOVEMENTS
• PROCEDURE FOR A PRIORITY RANKING SYSTEM FOR RAIL-HIGHWAY GRADE CROSSINGS
• RIGHT-TURN-ON-RED CHARACTERISTICS AND USE OF AUXILIARY RIGHT-TURN LANES
• VOLUME GUIDELINES FOR SIGNALIZATION OF DIAMOND INTERCHANGES