Let’s Play Date, Marry, Kill…with Roundabouts.
What are your thoughts as Indiana starts adopting these modern traffic control measures (Europe has been doing them since…forever)?
Most people I talk to either love or hate these intersections. For some reason, I can’t find people who are indifferent to them very often.
According to the Carmel’s city webpage: “Carmel is internationally known for its roundabout network. Since the late 1990’s Carmel has been building and replacing signalized intersections with roundabouts. Carmel now has more than 150 roundabouts, more than any other city in the United States.”
“The number of injury accidents in Carmel have reduced by about 80 percent and the number of accidents overall by about 40 percent.”
General PROs / CONs
- Up to a 90 percent reduction in fatalities
- 76 percent reduction in injury crashes
- 30-40 percent reduction in pedestrian crashes
- Reduces the severity of crashes
- Keeps pedestrians safer
- Roundabouts reduce the number of potential accident points within an intersection, 75 percent fewer conflict points than four-way intersections
- No signal equipment to install and repair, savings estimated at an average of $5,000 per year in electricity and maintenance costs
- Service life of a roundabout is 25 years (vs. the 10-year service life of signal equipment)
- Reduces pollution and fuel use
- 30-50 percent increase in traffic capacity, improves traffic flow for intersections that handle a high number of left turns, reduces need for turn lanes
- While roundabouts can handle moderate to heavy traffic volumes more efficiently than traditional intersections, they may experience congestion and delays during periods of extremely high traffic volumes or if not designed properly for the anticipated traffic flow
- Pedestrians and cyclists may face challenges navigating roundabouts, particularly multi-lane roundabouts with higher traffic volumes. Proper design considerations, such as providing safe crossing points, adequate sight lines, and dedicated pedestrian/cyclist facilities, are crucial to ensure their safety.
- Drivers unfamiliar with roundabouts may initially experience confusion or hesitation when navigating them, potentially leading to increased risks or delays until they become accustomed to the traffic patterns.
- Roundabouts generally require a larger footprint and more land area
https://www.in.gov/indot/traffic-engineering/roundabouts/#:~:text=Up to a 90 percent,points than four-way intersections (CONs came from general searching, LLM compilation)
Indianapolis and the surrounding suburbs are implementing them more frequently now, how about your city?
Did you know that traffic circles are different from roundabouts? PA has a little comparison chart that was interesting (If you’re into that sort of thing): https://www.penndot.pa.gov/PennDOTWay/pages/Article.aspx?post=24
Hello neighbor, Ohioian here. Columbus began using roundabouts about 10-12 years ago (or at least that’s when I started noticing them). They are vastly superior to four way and two way stops, and greatly superior to signaled interactions in most cases.
Where i see the biggest issues are in multi-lane intersections. Like, three or more lanes, not counting a right turn lane. It takes a LOT of planning and work from the engineering department to properly covert multi-lane intersections to roundabouts, but it is doable.
The cons are mostly related US car culture and “more lanes=better” old school thinking. If the DOT has the political will or a public mandate to do roundabouts right, it’ll succeed. Naysayers will eventually grumble at parties and generally be ignored.
I find one issue with multiple lanes is people assuming the inside lane driver will be continuing around instead of existing. This leads to drivers taking the outside lane and hitting someone as they are exiting.
It’s probably confusing to read that, but the golden rule I preach to people is yield to cars in the circle regardless of their lane and wait for them to pass by right as you pull out. Can’t go wrong that way.
No no i totally get it (even with the typo lol). There’s a roundabout in Dublin, Ohio at 161 and 33 that is only two lanes and had a number of accidents after it opened because of exactly what you described. I’ve seen some four lane roundabouts in Europe that look like absolute nightmares, but I imagine the locals don’t have many problems