Wednesday, May 12, 2010
Written by Nicole Rogers
LCG is ahead of the U.S. curve in regulating traffic.
Hollywood gave roundabouts a bad rap when it sent the Griswolds on a European vacation to...
Ridge Road at Rue De Belier is one of five roundabouts in use in
Lafayette Parish, but more are planned for the near future.
Wednesday, May 12, 2010
Written by Nicole Rogers
LCG is ahead of the U.S. curve in regulating traffic.
Hollywood gave roundabouts a bad rap when it sent the Griswolds on a European vacation to take on the Lambeth Bridge roundabout in London, resulting in the family circling the street like a gerbil caught in his spinning wheel.
Lafayette Consolidated Government's Traffic and Transportation Department is now following suit, putting itself ahead of the curve among American cities by drawing up plans for a plethora of roundabouts throughout the area to unsnarl problem intersections. The end result will have the department entering the age of modern traffic design - and hopefully eliminating much of the frustration of our daily commute.
"Roundabouts have been proven to be safe," says LCG engineer Chris Cole. "Roundabouts reduce collisions. It improves the level of service at an intersection. Level of service means, in essence, how fast can a vehicle get through an intersection comfortably?"
According to the Insurance Institute of Highway Safety, roundabouts reduce the risks of fatal collisions by 90 percent and overall collisions by 37 percent. In addition, Cole says, there are only eight "collision points" on a roundabout, compared with 32 collision points "at a conventional, signalized intersection."
Cole is part of the Metropolitan Planning Organization, a federally funded organization attached to LCG and some neighboring parishes; it is the key to the roundabout planning. Most of the roundabouts in the MPO's plan, however, are located in Lafayette Parish.
According to Cole, "the meat and potatoes" of the MPO plan is that "anyone that comes along and wants to propose any type of traffic control at any intersection in Lafayette Parish, they must first look at a roundabout as a potential solution for traffic control. When I say traffic control, I mean four-way stop, lights, yield signs, whatever it may be."
Lafayette first sought funding for its roundabouts from the federal Transportation Investments Generating Economic Recovery Grant, Cole says, applying for approximately $100 million to construct 121 roundabouts but received no funding. In response, the MPO decided to shake its $3.5 million coin purse and fund the construction itself. According to Cole, there is a total of 36 roundabouts in the plan, including five intersections already completed, 10 currently identified with funding and 21 locations that do not have funding.
The five roundabouts in use are at Ridge Road and Rue Du Belier; East Milton Avenue and Chemin Metairie Road; Youngsville Highway and Chemin Metairie extension; South Morgan Avenue and East Fairfield Drive; and Ardoin Memorial Drive and Sterling Center Drive.
All 10 funded roundabouts are set to be constructed as single-lane, Cole says. However, there is a concept drawing of a "turbo roundabout" for the intersection of Kaliste Saloom Road and E. Broussard Road.
"A turbo roundabout is like a spiral to where you don't have to change lanes," explains Warren Abadie, the traffic department's traffic signal and systems manager. "So, it's much more efficient than a traditional two-lane roundabout. You don't have to weave. In other words, if you want to go straight, you get in the left lane and it takes you right there. You don't have to cut across traffic."
According to an analysis compiled by Abadie ranking 18 intersections most in need of a roundabout, the intersection of Kaliste Saloom and E. Broussard is No. 1. The chart currently grades the intersection's level of service an F, and reveals that the intersection would be graded a B after construction of a roundabout.
"La Neuville is a close second. Bonin, La Neuville is terrible, also," Abadie adds.
That intersection is No. 2 on the list and also has a current level of service of F. Although the intersection falls below only one other intersection in the Lafayette area and construction of a roundabout would raise the level of service to a B, it is not currently funded.
Cole says construction of a roundabout at La Neuville Road and Bonin Road is not funded because they are parish-, as opposed to state-funded, roads.
"Kaliste and Broussard is a state road, Verot School and Milton 92 - state road; Ridge and Fieldspan - state road; Gloria Switch and 93 - state road; East Broussard and Milton - state road; La Neuville and Bonin - parish road," Cole reveals. "It probably has to do with funding. We probably didn't have the funds to build it. A lot of times the state comes up with the funds. If it's on their road, if it's on that state road, the state has funds."
The first of the 10 funded roundabouts to be built is No. 3 on Abadie's list: Verot School Road and Milton Avenue, which, according to Cole, will be built in May and June. He says the remaining nine roundabouts should be built within the next three years.
There are time-consuming traffic back-ups at both Kaliste Saloom-Broussard and Verot School-Milton during rush hours.
UL Lafayette Civil Engineering Professor Xiaoduan Sun says the roundabout is a sound concept: "Yes, it is safer and more efficient by reducing [the] number of conflicting points at an intersection and delay," he points out. " I think [drivers] will adjust [to] this new control method well."
Not only are roundabouts safer and faster, says Cole, they are also cheaper.
"They are more cost-efficient," he explains. "Let's compare lights; signalized lights have a cost. The light bulbs run out. They burn out. People have to go and install these lights. These lights burn electricity. Roundabouts have none of those. The construction [of a roundabout] is a cost, but the lights have perpetual maintenance. In the long run, roundabouts save money."
Traffic signals may increase capacity, Abadie says, but they potentially exacerbate the number of crashes, whereas a roundabout can reduce the number of collisions.
"Normally, as traffic engineers, we have to trade safety for capacity," Abadie adds. "In other words, we put in the traffic signal; it may increase the capacity of the intersection, but normally, it also increases the crashes. A roundabout is the best of both worlds. It increases the capacity, and it decreases the crashes. So, it's safer and more efficient."
"If you look in the United States, there aren't very many cities into building roundabouts," points out Cole. "Roundabouts first became really big in Europe, and they've kind of grown over here. I think it's a logical solution to traffic control, a cheaper solution than what we're doing today. Lafayette - I think we're pretty cutting edge as far as trying new traffic control devices."