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
Personally, I went from hating this idea, to loving it after I starting driving in them.
After spending time driving in Carmel, I can’t stand traffic lights anymore. Everything got downgraded in my mind: Traffic lights became stop signs, stop signs became yield, yield became…well still yield (I’m not a sociopath).
Sound places have built terrible versions of roundabouts, so I’m sure those populations aren’t impressed.
I did drive through one that was off an interstate exit and had heavy tractor-trailer traffic, that actually directly connected to a truck stop. To my surprise, it was glorious. It was fairly large, so the trucks had plenty of ability to go around without running over curbs, and it made all the traffic going in and out of the big truck stop / gas station pretty smooth. I was genuinely impressed. I think it was southern Indiana around the 69 project, but I can’t remember.
Love them! Just got back to the US after driving around Portugal and Spain. I especially love the ones that replace what would typically be a string of 4 way stops with traffic lights. It is great, especially when there’s no traffic, to be constantly moving rather than stopping, waiting, and starting. Also, can’t complain about the huge (well studied and documented) impact on safety.
Edit: Also, I hate traffic circles! My wife and I use the 4 way stop, traffic circles, and roundabouts as analogies of different types of solutions. Roundabouts are the ideal solution (saves lives, land, $$, etc.), 4 way stops are less than ideal solutions that work, and traffic circles are the worst of both worlds.
Traffic circles do frustrate me as well. It’s big enough to be a roundabout, but they wasted the money for lights, and have higher speeds.
Westfield, did that at state road 31 and 32. It’s a silly intersection, could have been great.