05-03-2016, 06:40 AM
Just opening day jitters. They work elsewhere in Hawai'i, why not the big island?
Modern, slow and go, roundabout intersections have less delay than a stop light or stop sign, especially the other 20 hours a day people aren’t driving to or from work (it’s the #2 reason). Average daily delay at a signal is around 12 seconds per car. At a modern roundabout average delay is less than five seconds. Signals take an hour of demand and restrict it to a half hour, at best only half the traffic gets to go at any one time. At a modern roundabout drivers entering from different directions can all enter at the same time. Don’t try that with a signalized intersection.
Single-lane modern roundabouts (90-120 feet in diameter) can handle intersections that serve about 20,000 vehicles per day with peak-hour flows between 2,000 and 2,500 vehicles per hour. Two- and three-lane modern roundabouts (150-220 feet in diameter) can serve about 50,000 vehicles per day and handle 2,500 to 5,500 vehicles per hour. Right-turn slip lanes can increase those numbers if needed (just like for signal intersections). Much depends on how balanced the entries are, but only in determining how many lanes are needed for each movement.
If you read the link, 8 of 116 crashes resulted in injuries, about 7%, and they didn't even discuss severity. Can you say the same for any similar intersection in the area? What the article doesn't mention is how many drivers enter those intersections each day. An apples to apples comparison would be crash rate, not total number of crashes. Crash rate accounts for exposure.
Modern roundabouts are the safest form of intersection in the world (much more so than comparable signals). Visit http://www.iihs.org/iihs/topics/t/rounda...icoverview for modern roundabout FAQs and safety facts. Modern roundabouts, and the pedestrian refuge islands approaching them, are two of nine proven safety measures identified by the FHWA, http://tinyurl.com/7qvsaem
The FHWA has a video about modern roundabouts on Youtube, or check out the IIHS video (iihs dot org).
http://priceonomics.com/the-case-for-mor...undabouts/
http://safety.fhwa.dot.gov/intersection/...undabouts/
Modern, slow and go, roundabout intersections have less delay than a stop light or stop sign, especially the other 20 hours a day people aren’t driving to or from work (it’s the #2 reason). Average daily delay at a signal is around 12 seconds per car. At a modern roundabout average delay is less than five seconds. Signals take an hour of demand and restrict it to a half hour, at best only half the traffic gets to go at any one time. At a modern roundabout drivers entering from different directions can all enter at the same time. Don’t try that with a signalized intersection.
Single-lane modern roundabouts (90-120 feet in diameter) can handle intersections that serve about 20,000 vehicles per day with peak-hour flows between 2,000 and 2,500 vehicles per hour. Two- and three-lane modern roundabouts (150-220 feet in diameter) can serve about 50,000 vehicles per day and handle 2,500 to 5,500 vehicles per hour. Right-turn slip lanes can increase those numbers if needed (just like for signal intersections). Much depends on how balanced the entries are, but only in determining how many lanes are needed for each movement.
If you read the link, 8 of 116 crashes resulted in injuries, about 7%, and they didn't even discuss severity. Can you say the same for any similar intersection in the area? What the article doesn't mention is how many drivers enter those intersections each day. An apples to apples comparison would be crash rate, not total number of crashes. Crash rate accounts for exposure.
Modern roundabouts are the safest form of intersection in the world (much more so than comparable signals). Visit http://www.iihs.org/iihs/topics/t/rounda...icoverview for modern roundabout FAQs and safety facts. Modern roundabouts, and the pedestrian refuge islands approaching them, are two of nine proven safety measures identified by the FHWA, http://tinyurl.com/7qvsaem
The FHWA has a video about modern roundabouts on Youtube, or check out the IIHS video (iihs dot org).
http://priceonomics.com/the-case-for-mor...undabouts/
http://safety.fhwa.dot.gov/intersection/...undabouts/