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How do La Jolla Boulevard roundabouts rate?
“Even a bad roundabout is going to function better than a good signal intersection.”
Crossroads Roundabout on La Jolla Blvd.
We need Mr. Roundabout!
Scott Ritchie has been called “The Roundabout Guy” ever since he started a company called “Roundabouts & Traffic Engineering” back in 1998. To most of us, the modest roundabout may still feel like a quaint, annoying import from Europe, especially if you’re slowing down onetwothreefourfive times while navigating the roundabouts along that obstacle course known as La Jolla Boulevard.
But not Scott Ritchie. He’s a transportation engineer who swears roundabouts are the answer to driving’s most dangerous challenge: intersections. A quarter of all US road deaths happen there. “Studies have been done into highway safety. Comparing a modern roundabout to a ‘Stop’-controlled, or even a signalized-controlled intersection, you have a 90 percent reduction in fatalities. You have an average of an 80 percent reduction in injury-producing accidents. Those two statistics, which are consistent not just nationally but internationally, are the reason modern roundabouts have done so well in the last ten years. Yes you may get frustrated, because you have to slow down, and you’re not sure if the guy is going to yield to you or not, but even if [you hit someone, in a roundabout], you’re talking speeds of 20 mph! So just in terms of the safety statistics, why would planners not consider a modern roundabout at every intersection?”
Scott Ritchie
He says roundabouts really didn’t catch on as a viable intersection alternative until the year 2000. “We had more and more of them built, and the safety statistics that came out of the UK, France, Germany, Australia, were proving to be true in the US as well.” It’s not that they’re new: the first circular intersection ever built for vehicles was in 1905, he says: Columbus Circle in New York City. “It is still in existence today. Back then, they weren’t known as modern roundabouts, they were just circular intersections.”
It wasn’t until November of 1966 that the UK finally initiated what Ritchie says is the most crucial roundabout law of all, “Yield to circulating traffic.” “They studied that ‘Yield’ condition for about nine years in the UK, and they found that ‘Boy, this [roundabout] is not a series of intersections all around the circle; it’s actually one holistic device. And that holistic device functions as a result of the geometry that’s imposed by the design.’” Of course, there are good roundabouts, and not so good roundabouts. “Some [designers] don’t know what they’re doing. They get a coffee can, they turn it upside down, they draw a circle, and they call it a roundabout. Especially in multi-lane scenarios, you’ll see a lot of bad design. Because what makes a modern roundabout function properly is speed control. If you slow everybody down to 25 mph, and have them drive around an object — which is not always circular — you are eliminating four times the number of potential accidents. A standard intersection has 32 points of conflict, whereas a circular intersection only has eight. So in November of 1966, they made it law that if you’re entering a roundabout, you must yield to those [cars] which are [already] circulating. Crucial. Contrary to the belief that the ‘yield’ condition would actually reduce capacity in the intersection, it increased it, because the jam-up went away as soon as you assigned the right priority to the traffic.”
Translation: “You can’t enter the circular intersection until you have yielded to someone already in the circle.” In the bad old days, you’d enter in, and whichever lane had the most traffic would dominate the entire circle. There was no ‘Yield’ control. “They were very dangerous. We didn’t bring the ‘Yield’ sign to the United States till 1959. Our first modern roundabout was built in Las Vegas, Nevada in 1990. We were very far behind the rest of the world in terms of the modern roundabout. They quickly learned that signalizing roundabouts does not work. They’d make it four times worse. So they ended up taking out the signal, and converting them to smaller, modern roundabouts, and all of a sudden, they started working!”
Crossroads Roundabout sign
Says Ritchie, “The whole concept is to get everyone to enter into the roundabout with what I call self-enforcing geometry. And that self-enforcing geometry is essentially the design of the roundabout. If you have a proper design, by somebody who really understands roundabouts, it’s going to function with that self-enforcing speed control to get everyone to enter in at roughly 25 mph, circulate around the roundabout and exit. And if it has been done right, it’s very comfortable to drive.”
So how does La Jolla Boulevard rate, with its five roundabouts? Not so great. “Unfortunately, too many people are drawing these coffee-can circles and calling them roundabouts when they’re really just old traffic circles with very uncomfortable geometry, very abrupt, tight entries, and tight exits. La Jolla Boulevard has fairly constrained, tight, small, dingaling roundabouts. And they have flaws, such as lack of safe distance [visibility] due to overgrown landscaping. But in general, even a bad roundabout is going to function better than a good signal [intersection], both in capacity and safety.”
Plus, roundabouts are cheaper. Way cheaper. “You don’t need the technology, traffic lights, actuators, sensors to trip the signals, video detection, loop detectors, magnets in the road to sense the vehicle, blah blah blah. With a modern roundabout, you don’t have anything to break!” Ritchie says a typical traffic signal is going to run about $30,000-$40,000 per year, just to maintain. “The only thing you need to maintain a modern roundabout is the landscaping! Imagine a corridor like La Jolla Boulevard: you’ve got five roundabouts in a row. If those were signals, you’d be looking at about half a million a year, just to maintain the existing signals. But if you were going to create a whole new roundabout, you’d be thinking $5-600,000 as a one-time cost. No comparison!
But above all this, Ritchie says he’s touting his “back to the future” concept for one reason: “I’m in the business of saving lives. I’ll give you one more example: For the first modern roundabout ever put on a state highway in Arizona, I did ‘before’ and ‘after’ studies. Before, you had 24 injury-producing accidents and five fatalities during the last three years of the signals. During the last five years of the modern roundabout that replaced them, there were zero fatalities, and zero injury-producing accidents. So based on those statistics, why would you not consider [replacing lights with] a modern roundabout?”
Here's something you might be interested in.
How do La Jolla Boulevard roundabouts rate?
“Even a bad roundabout is going to function better than a good signal intersection.”
How do La Jolla Boulevard roundabouts rate?
“Even a bad roundabout is going to function better than a good signal intersection.”
Crossroads Roundabout on La Jolla Blvd.
We need Mr. Roundabout!
Scott Ritchie has been called “The Roundabout Guy” ever since he started a company called “Roundabouts & Traffic Engineering” back in 1998. To most of us, the modest roundabout may still feel like a quaint, annoying import from Europe, especially if you’re slowing down onetwothreefourfive times while navigating the roundabouts along that obstacle course known as La Jolla Boulevard.
But not Scott Ritchie. He’s a transportation engineer who swears roundabouts are the answer to driving’s most dangerous challenge: intersections. A quarter of all US road deaths happen there. “Studies have been done into highway safety. Comparing a modern roundabout to a ‘Stop’-controlled, or even a signalized-controlled intersection, you have a 90 percent reduction in fatalities. You have an average of an 80 percent reduction in injury-producing accidents. Those two statistics, which are consistent not just nationally but internationally, are the reason modern roundabouts have done so well in the last ten years. Yes you may get frustrated, because you have to slow down, and you’re not sure if the guy is going to yield to you or not, but even if [you hit someone, in a roundabout], you’re talking speeds of 20 mph! So just in terms of the safety statistics, why would planners not consider a modern roundabout at every intersection?”
Scott Ritchie
He says roundabouts really didn’t catch on as a viable intersection alternative until the year 2000. “We had more and more of them built, and the safety statistics that came out of the UK, France, Germany, Australia, were proving to be true in the US as well.” It’s not that they’re new: the first circular intersection ever built for vehicles was in 1905, he says: Columbus Circle in New York City. “It is still in existence today. Back then, they weren’t known as modern roundabouts, they were just circular intersections.”
It wasn’t until November of 1966 that the UK finally initiated what Ritchie says is the most crucial roundabout law of all, “Yield to circulating traffic.” “They studied that ‘Yield’ condition for about nine years in the UK, and they found that ‘Boy, this [roundabout] is not a series of intersections all around the circle; it’s actually one holistic device. And that holistic device functions as a result of the geometry that’s imposed by the design.’” Of course, there are good roundabouts, and not so good roundabouts. “Some [designers] don’t know what they’re doing. They get a coffee can, they turn it upside down, they draw a circle, and they call it a roundabout. Especially in multi-lane scenarios, you’ll see a lot of bad design. Because what makes a modern roundabout function properly is speed control. If you slow everybody down to 25 mph, and have them drive around an object — which is not always circular — you are eliminating four times the number of potential accidents. A standard intersection has 32 points of conflict, whereas a circular intersection only has eight. So in November of 1966, they made it law that if you’re entering a roundabout, you must yield to those [cars] which are [already] circulating. Crucial. Contrary to the belief that the ‘yield’ condition would actually reduce capacity in the intersection, it increased it, because the jam-up went away as soon as you assigned the right priority to the traffic.”
Translation: “You can’t enter the circular intersection until you have yielded to someone already in the circle.” In the bad old days, you’d enter in, and whichever lane had the most traffic would dominate the entire circle. There was no ‘Yield’ control. “They were very dangerous. We didn’t bring the ‘Yield’ sign to the United States till 1959. Our first modern roundabout was built in Las Vegas, Nevada in 1990. We were very far behind the rest of the world in terms of the modern roundabout. They quickly learned that signalizing roundabouts does not work. They’d make it four times worse. So they ended up taking out the signal, and converting them to smaller, modern roundabouts, and all of a sudden, they started working!”
Crossroads Roundabout sign
Says Ritchie, “The whole concept is to get everyone to enter into the roundabout with what I call self-enforcing geometry. And that self-enforcing geometry is essentially the design of the roundabout. If you have a proper design, by somebody who really understands roundabouts, it’s going to function with that self-enforcing speed control to get everyone to enter in at roughly 25 mph, circulate around the roundabout and exit. And if it has been done right, it’s very comfortable to drive.”
So how does La Jolla Boulevard rate, with its five roundabouts? Not so great. “Unfortunately, too many people are drawing these coffee-can circles and calling them roundabouts when they’re really just old traffic circles with very uncomfortable geometry, very abrupt, tight entries, and tight exits. La Jolla Boulevard has fairly constrained, tight, small, dingaling roundabouts. And they have flaws, such as lack of safe distance [visibility] due to overgrown landscaping. But in general, even a bad roundabout is going to function better than a good signal [intersection], both in capacity and safety.”
Plus, roundabouts are cheaper. Way cheaper. “You don’t need the technology, traffic lights, actuators, sensors to trip the signals, video detection, loop detectors, magnets in the road to sense the vehicle, blah blah blah. With a modern roundabout, you don’t have anything to break!” Ritchie says a typical traffic signal is going to run about $30,000-$40,000 per year, just to maintain. “The only thing you need to maintain a modern roundabout is the landscaping! Imagine a corridor like La Jolla Boulevard: you’ve got five roundabouts in a row. If those were signals, you’d be looking at about half a million a year, just to maintain the existing signals. But if you were going to create a whole new roundabout, you’d be thinking $5-600,000 as a one-time cost. No comparison!
But above all this, Ritchie says he’s touting his “back to the future” concept for one reason: “I’m in the business of saving lives. I’ll give you one more example: For the first modern roundabout ever put on a state highway in Arizona, I did ‘before’ and ‘after’ studies. Before, you had 24 injury-producing accidents and five fatalities during the last three years of the signals. During the last five years of the modern roundabout that replaced them, there were zero fatalities, and zero injury-producing accidents. So based on those statistics, why would you not consider [replacing lights with] a modern roundabout?”
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