Draft version scheduled for mid-June. Revised version based on reviewers comments expected Sept or Oct. Completion by end of year. Good Traffic Calming Basics article in Jan 2000 'Civil Engineerng' magazine. Contact Elliott for copy . Speed humps are often used in Portland OR now instead of traffic circles.
Humps reduce speed between intersections.
Portland uses 14 ft long x 3 inch high parabolic humps instead of 12 ft long, which they found too abrupt. Also use 22 ft long humps on higher volume streets. Also experimenting with removable rubber humps for temporary use at construction zones, etc.