What are roundabouts? A transportation engineer explains the safety benefits of these circular intersections

If you’ve been driving through U.S. cities and towns, you’ve likely noticed an increase in roundabouts replacing traditional four-way intersections. Some drivers embrace them as an efficient traffic solution, while others find them confusing or even intimidating.

But what exactly is a roundabout, and why is it becoming a preferred alternative to stop signs and traffic signals? Roundabouts are not just about traffic flow—they are a safer, more efficient, and environmentally friendly way to design roads.

Let’s break down what roundabouts are, how they work, and why they are considered one of the most effective traffic management solutions today.

What is a Roundabout? Understanding the Basics

A roundabout—also known as a rotary or traffic circle—is a circular intersection where vehicles move counterclockwise around a central island. Unlike traditional intersections controlled by stop signs or traffic lights, roundabouts operate using a yield-at-entry system, meaning:

✔ Drivers entering the roundabout must yield to vehicles already circulating.
✔ Traffic flows continuously, reducing congestion and unnecessary stops.
✔ Speeds are naturally reduced, leading to safer driving conditions.

Most roundabouts also include:

🔹 Splitter islands – Raised medians that help slow down traffic before entering.
🔹 Pedestrian crosswalks – Positioned away from the central island to increase safety.
🔹 Lane markings – Clear indicators help guide drivers into the correct exit lane.

The result? A smoother, safer, and more efficient intersection that reduces both traffic delays and accidents.

A Brief History of Roundabouts

Many people assume roundabouts are a modern innovation, but their history dates back hundreds of years.

Video : Roundabout Safety Benefits

1700s – Early versions of circular intersections appeared in Europe, particularly in England and France.
1800s-1900s – Washington, D.C. was designed with multiple traffic circles, inspired by European models.
1950s – The United Kingdom introduced the yield-at-entry rule, transforming roundabouts into the efficient system we use today.
1990s – The first modern roundabout in the U.S. was built in Summerlin, Nevada in 1990.
Today – Over 10,000 roundabouts exist in the United States, with more being installed every year.

While roundabouts have been common in Europe and Australia for decades, the U.S. is now rapidly adopting them due to their proven safety and efficiency benefits.

Why Roundabouts Are Safer Than Traditional Intersections

One of the biggest reasons cities are replacing traditional intersections with roundabouts is safety.

1. Fewer Conflict Points = Fewer Accidents

A typical four-way intersection has 32 conflict points—areas where vehicle paths cross, increasing the risk of collisions. In contrast, a roundabout reduces conflict points to just 8.

This means:

✔ No head-on collisions
✔ No dangerous T-bone crashes
✔ Fewer high-speed impacts

According to the Federal Highway Administration (FHWA), roundabouts can reduce serious and fatal crashes by up to 90% when replacing a stop-controlled intersection. Even when replacing a traffic signal intersection, they reduce serious crashes by nearly 80%.

2. Lower Speeds = Less Severe Collisions

In a roundabout, vehicles enter and exit at lower speeds (15-25 mph), compared to the higher speeds (40-50 mph) seen at traditional intersections.

Lower speeds lead to:

✔ Less severe crashes
✔ Fewer pedestrian injuries
✔ Easier decision-making for drivers

3. Safer for Pedestrians and Cyclists

Roundabouts offer better protection for pedestrians because:

✔ Crosswalks are set back from the circular flow, allowing drivers to see pedestrians clearly.
✔ Pedestrians only cross one direction of traffic at a time, making crossings safer.
✔ Cyclists can either merge into traffic or use a designated bike path, depending on the design.

With these safety features, roundabouts significantly reduce pedestrian-related accidents compared to traditional intersections.

Efficiency: Why Roundabouts Improve Traffic Flow

Beyond safety, roundabouts are also more efficient than stop signs or traffic lights.

1. Less Waiting, More Moving

At a traditional intersection, cars must stop at red lights, even when there’s no cross traffic. In a roundabout:

✔ Traffic keeps moving – No unnecessary stops.
✔ Fewer backups – No long wait times during rush hour.
✔ Reduced driver frustration – No more waiting for a green light when there’s no oncoming traffic.

2. Eliminating Left Turns = Smoother Flow

One of the most dangerous and disruptive movements at an intersection is the left turn. Roundabouts eliminate left turns, forcing all vehicles to move in the same direction, improving:

✔ Traffic efficiency – No waiting for gaps in oncoming traffic.
✔ Driver decision-making – No confusion about when to turn.

3. Roundabouts Handle High Traffic Volumes Better

Unlike stop signs and traffic lights, which cause congestion during peak hours, roundabouts allow continuous movement, making them ideal for high-traffic areas.

Environmental Benefits: How Roundabouts Help the Planet

Roundabouts aren’t just safer and more efficient—they also have environmental advantages.

1. Reduced Fuel Consumption

✔ Less idling at red lights = less wasted fuel
✔ Lower speeds = better fuel efficiency

According to studies, roundabouts can reduce fuel consumption by up to 30%, making them a cost-effective solution for drivers.

2. Lower Carbon Emissions

Fewer stops and starts mean lower emissions, helping reduce air pollution in urban areas. Cities that replace signalized intersections with roundabouts see:

✔ Less smog and pollution
✔ Improved air quality

3. Less Road Maintenance Required

✔ No traffic signals = lower maintenance costs
✔ Roundabouts last longer than traffic lights

With less infrastructure to maintain, roundabouts save cities money in the long run.

Challenges: Why Some Drivers Struggle with Roundabouts

Despite their many benefits, some drivers remain hesitant about roundabouts. Common challenges include:

🚦 Confusion about yielding – Some drivers don’t understand that they must yield to circulating traffic before entering.
🚦 Merging issues – Drivers unfamiliar with roundabouts sometimes hesitate, causing unnecessary slowdowns.
🚦 Exit mistakes – Some drivers find it difficult to choose the correct exit and miss their turn.

However, studies show that once drivers become familiar with roundabouts, their confidence improves significantly.

Video : Principles of Intersection Safety

Final Thoughts: Are Roundabouts the Future of Road Design?

Roundabouts are more than just a traffic trend—they are a safer, smarter, and greener solution for modern transportation. With their ability to reduce crashes, improve traffic flow, and lower emissions, they are quickly becoming a preferred alternative to traditional intersections.

🚗 Safer roads, fewer accidents
🚗 Smoother traffic, less congestion
🚗 Lower fuel costs, reduced pollution

As more states adopt roundabouts in urban and suburban planning, they will likely become a permanent feature of America’s roadways.

So next time you approach a roundabout, embrace the change—it’s making our roads safer and more efficient for everyone!

Carly Simon finally says who “You’re So Vain” is written about, confirms what we knew all along

With two successful albums in the span of only nine months, Simon soon found herself solidified as a famous and immensely popular singer/songwriter. In 1971, she received a Grammy Award for Best New Artist of the Year, and additionally one nomination in the “Best Pop Female Vocalist” category.

Carly Simon – “You’re So Vain”

In November of 1972, Carly Simon released her third album, and it was intended to be her big commercial breakthrough. No Secrets spent five weeks at No. 1 on the US Billboard 200 chart and quickly achieved gold status.

It was a great album that spread all over the world, spending weeks and weeks on the top of the charts in countries like Norway, Australia and Canada. But it was one song in particular – the third on the album – that would change her life forever.

You’re So Vain was the song that most people reference when talking of Carly Simon. It was a smash-hit right away, and throughout the years, it’s grown even bigger and bigger.

The song is currently ranked at No. 92 on Billboard‘s Greatest Songs of All-Time list. In 2014, it was voted as number as no 216 when Recording Industry Association of America (RIAA) asked the question of the best songs of the century. That same year, it was crowned as the ultimate song of the 1970’s by the UK Official Charts Company.

The album was recorded at the famous Trident Studios in London, England, where bands like The Beatles recorded The White Album and David Bowie made Space Oddity.

You’re So Vain – recording

You’re So Vain also held plenty of secrets when it was released, and for many years it was the subject of one of rock ‘n’ roll’s biggest mysteries. But we’ll get to that soon.

Firstly, Rolling Stones frontman Mick Jagger is uncredited on the song, even though he sings on the chorus.

At the time of the recording, several other famous artists were at the Trident Studios, and the likes of Paul McCartney, Linda McCartney, legendary record producer George Martin, and Harry Nilsson watched her record. Actually, McCartney himself pitched in to guest star with background vocals.

And then there was Mick Jagger. Carly Simon wrote in her memoir that he actually invited himself to the recording. Jagger had pursued her in London and called Trident Studios once he understood she was there.

“It was shortly after midnight. Mick and I, we were close together – the same height, same coloring, same lips,” Simon writes.

“I felt as if I was trying to stay within a pink gravity that was starting to loosen its silky grip on me. I was thrilled by the proximity, remembering all the times I had spent imitating him in front of my closet mirror.”

As mentioned, You’re So Vain was a rock ‘n’ roll mystery. It’s always fun to know the background story of a song, wether its about a certain event, a person, or if that one line is a reference for something special.

You’re So Vain – who is it about?

In Carly Simon’s case, no one knew who You’re So Vain was about.

Some guessed – and had conspiracy theories – that the song was about Mick Jagger. Sure, there was a pretty clear connection between the two, especially since he actually sang on the record.

But no, it turns out the rumours were wrong. The truth is that You’re So Vain – at least the second verse – is about one-time Hollywood lothario Warren Beatty, whom she dated briefly in the early 1970’s.

“You had me several years ago when I was still quite naive.
Well you said that we made such a pretty pair.
And that you would never leave.
But you gave away the things you loved and one of them was me.
I had some dreams, they were clouds in my coffee.
Clouds in my coffee”.

In her memoir, Carly revealed that the song was also about two other people, but she won’t reveal who they were.

“I don’t think so,” she told People. “At least until they know it’s about them.”

“Probably, if we were sitting over at dinner and I said: ‘remember that time you walked into the party and…’ I don’t know if I’ll do it. I never thought I would admit that it was more than one person.”

Simon dated Warren Beatty for a short while in the ’70s, and described him as a “glorious specimen” who put all other men “to shame, if looks and charm were what you were after.”

Carly Simon – James Taylor

So what about Carly Simon’s love life besides Warren? Well, she’s been married once, to singer/songwriter James Taylor.

They had met briefly as children, and then again in her dressing room in 1971. She described the latter meeting in her book. Taylor was there together with his then-girlfriend Joni Mitchell.

“He was barefoot, long-legged, long-footed – and is knees were bent,” she wrote in her memoir.

”He wore dark red, loose, wide-wale corduroys and a long-sleeved Henley with one button open, his right hand clutching a self-rule cigarette. His hair, simultaneously shiny and disheveled, fell evenly on both sides of his head, and he wore a scruffy, understated mustache, the kind so fashionable back in the yearly 1970s. He seemed both kempt and unkempt. Even sprawled out on the floor, everything about him communicated that he was, in fact, the center of something – the core of an apple, the center of a note.”

Carly Simon and James Taylor started dating later the same year and tied the knot in November of 1972. 11 years later, the couple divorced, but it wasn’t just because they didn’t have the same love for each other anymore.

Carly Simon – children

Simon explained that it mostly had to do with drugs. They had two children, now grown up and working in the music business. Daughter Sally Taylor is 46 years old and Ben Taylor’s 43.

Her memoir Boys in the Trees pretty much ends with her marriage to James Taylor. Her son hasn’t read the book. But her daughter has.

“I think he would feel more conflicted than Sally did,” Simon told ABC in 2016. “I had told her almost everything, but when she read it all together, she was just so amazed. She said, ‘I’m so proud of you for being able to tell it like it is for you.’”

Carly Simon was later engaged to musician Russ Kunkel in 1985. She married writer James Hart in December 1987, but the couple divorced in 2007.

Carly Simon, now 75 years of age, continued making music for many years to come. And, as a by-product, continued to win several awards for her trophy cabinet.

Her 1977 worldwide hit Nobody Does It Better was the theme song of the Bond movie The Spy Who Loved Me. It’s considered by many to be one of the greatest Bond anthems of all time.

Hall of Fame entry

In 1988, she released the song Let The River Run, first featured in the 1988 movie Working Girl. With the song, she became the first singer ever to win three major awards for a single track: an Academy Award, a Grammy and a Golden Globe.

Six years later, in 1994, Carly was inducted into the Songwriters Hall of Fame.

Carly Simon lived a happy life during the 1960s and 1970s. She sure is a legendary singer with a legacy that will live on forever.

Thank you for all the wonderful music, Carly, and we hope to hear more in the future.

Please, share this story with friends and family!

When Carly Simon wrote the song You’re So Vain, her career changed forever, and yet the song remains one of rock ‘n’ roll’s biggest mysteries. Who is the person Simon is singing about?

Well, Carly herself has revealed who the classic song is about.

The 1970’s sure was a time for great music. During the 1960’s, bands like The Beatles had conquered the world, and now it was time for the likes of Bob Dylan and others to take over.

Carly Simon – singer/songwriter

One of those who did just that was Carly Simon. The wonderful singer/songwriter became one of the most popular artists when her career began to grow in the early 1970’s.

We’ve all heard You’re so Vain and various other classics from the New Yorker. But what about her life? And who was You’re so Vain actually about? This is the story of the wonderful Carly Simon.

Carly Simon was born on June 25, 1945, in New York City, the youngest daughter of an upper-class New York family. Her father Richard Simon was the co-founder of the Simon & Schuster publishing company.

Carly Simon – childhood

Now, Carly’s childhood wasn’t exactly perfect. As a third daughter, she often felt inadequate. Did her parents really want her?

“After two daughters he’d been counting on a son, a male successor to be named Carl. When I was born, he and Mommy simply added a y to the word, like an accusing chromosome: Carly,” she said.

When she was just 7 or 8 years old, Carly experienced a string of disturbing sexual encounters with a teenage boy.

“I didn’t realize that I was being used,” she said in an interview with USA Today. “I thought of myself as being in love with him. I’m sure a lot of girls go through the same thing.”

As a young girl, Carly got to see what the music industry was all about. But it would be some time before she would become the sensation she was.

Simon split her time between her family’s townhouse in Greenwich Village, New York and a wonderful estate in Stamford, Connecticut. The estate in Stamford saw the young girl surrounded by celebrities like Albert Einstein and Eleanor Roosevelt.

The Simon family were also good friends of legendary baseball player Jackie Robinson, who soon would take Carly under his wing. Jackie Robinson and his family lived in the Stamford house while their own home was under construction.

Befriended Jackie Robinson

She got to sit in the dugout at the old Ebbets Field in Brooklyn – home of the then-Brooklyn Dodgers. Soon, she became the unofficial mascot of the team.

“Jackie even taught me how to bat lefty, though it never took”, Simon wrote in her memoir Boys in the Trees (2015).

“He always had the cutest look around the side of his mouth, as if he were thinking about what he was about to say before he said it.”

However, the family would go through a tragedy. Simon’s father was strong-armed out of his own company, and died in 1960, just before his daughter’s 16th birthday.

For her part, Carly showed an early interest in music. She started singing together with brother Joey – who later became a successful writer, writing the music for the Broadway show The Secret Garden – but later, it was her and her sister who would go on to pursue a career in the business.

As Carly wrote on her website, she and sister Lucy taught themselves three chords on the guitar and hitch-hiked up to Provincetown, MA in the summer of 1964.

The Simon Sisters – as they called themselves – sang at a local bar called The Moors, with a repertoar consisting of folk music, as well as some of their own songs.

Touring with sister Lucy

Carly Simon and Lucy were eventually signed to Kapp Records and played a couple of clubs in Greenwich Village, opening for early comedians Woody Allen and Dick Cavett, among others, and even played in the UK.
In her memoir, Simon recalls the boat trip across the Atlantic heading home.

They were on the same boat as Sean Connery, and Carly and her sister ended up spending the trip with the actor. At that point, of course, no one could realize or even imagine that Carly would write a Bond theme song 12 years later.

The sister duo released three albums in the 1960s before Lucy left to get married.

Carly Simon was on her own, but still determined to forge a career in the music industry. However, her career had a slow start. She started working as a summer-camp counselor and as a secretary on a TV show.

Carly’s career

In February of 1971, Simon released her debut album Carly Simon. The song That’s the Way I’ve Always Heard It Should Be – an anti-marriage-song – became her first hit, reaching No. 10 on the Billboard Hot 100 list.

In October, later the same year, Simon released her second album, Anticipation. By now, things had really started to blow up. Her album went gold in two years and contained the smash hit Anticipation, which peaked at No. 13 on the Billboard pop singles chart and also at No. 3 on the Billboard Adult Contemporary chart in the United States.

According to herself, Simon wrote the song in just 15 minutes while waiting for Cat Stevens at her place, whom she was dating at the time and had made dinner for. When he arrived, the song was ready, but the date only lasted a short while.

“He gave me whispers and drawings of Blake poems,” Carly Simon said. “He told me about his childhood, his mixed Greek and Swedish parents, and we made a connection that has lasted.”