Abby Nadeau
Community Editor

Continuing from last weekís installment of the West Broadway roundabout series, this week we will be looking at how the roundabouts topic came to fruition and the research that was done to make them a possibility.

Washington Countyís West Broadway Reconstruction Project Manager Mike Rogers was given over 65 various questions to ask about the West Broadway Roundabout Reconstruction Project.

Such topics concerning planning, logistics, emergency vehicles, public works, traffic flow and the future of the roundabouts were given to Rogers.

Over the next month the Forest Lake Times will be printing Rogersí response to the questions along with supplemental stories.

Written below are a few of the questions raised. The questions are in no particular order.

1. Have there been any failed roundabouts?

Yes

A. What went wrong?

A notable example of a roundabout that initially failed is Clearwater, FL. This roundabout was constructed to bring five streets into one intersection and remove multiple traffic signals.

Its design included a large fountain in the center that sprayed water on motorists in the circle.

It also had nearly 90 degree right turns into and out of the roundabout. These turns caused path overlap (i.e. left lane crosses the right lane to exit/enter the roundabout) causing crashes.

Additional circular intersections that have failed include many East Coast traffic circles and rotaries. These are what many people believe are roundabouts, but they are quite different from what modern roundabouts really are. Traffic circles are much larger in design 600-700í in diameter vs. modern roundabouts 90í-250í in diameter. These larger sizes increased speed and weaving conflicts reducing safety. Also, many of them had traffic in the circle yield to entering traffic, or had entrances with traffic lights. In cases of heavy traffic entering a circle, the yielding traffic in the circle would eventually back up around the circle to the point where the entering traffic could no longer enter. When this happened the circle locked up and no longer worked.

B. How did the city fix the problem?

The city hired an expert in roundabout design to fix the roundabout. The fix included removing the nearly 90 degree turns and softening them so that vehicle paths did not over lap. It also involved better signage and striping so people knew which lane to be in.

Finally, the pedestrian crossings were moved back from the roundabout to allow drivers to focus on pedestrians and the roundabout separately.

The roundabout now functions significantly better and crashes have been nearly eliminated.

It handles 50,000 vehicles per day and 5000 pedestrians per day during spring break. Additionally, the fountain was removed due to its impact on drivers and maintenance cost.

2. When did the roundabouts come into the picture?

Many options have been analyzed for this corridor.

Initially the analysis did not include roundabouts. When they were suggested, they were added to the list of alternatives which was a good thing because based on the criteria used to evaluate all the alternatives, roundabouts stood out as the best way to manage the current and forecast 2028 traffic volumes on West Broadway Avenue.

A. Were there always going to be seven roundabouts?

No, initially roundabouts were only analyzed for four intersections (19th Street, East and West ramps, and 12th Street).

However, based on traffic modeling and input from the Business Task Force and project staff, the preferred option expanded the number of roundabouts by three (7th Street, 4th Street, and US- 61) to total seven for the corridor.

B. Who thought up the idea?

Roundabouts have been used successfully since 1990 in a number of states including Wisconsin, Colorado, and New York.

Recently, the use of modern roundabouts in Minnesota has gained popularity. The use of roundabouts on West Broadway Avenue was developed as a result of input from county, city and state engineers, elected officials, and public input from businesses and residents.

3. What makes seven roundabouts the best option for this stretch of W. Broadway?

They are the best option because of the following:

ï Roundabouts provide a better overall level of service (less delay) than traffic signals, particularly at the 12th Street and US- 61 intersections. Additionally, roundabouts provide additional roadway capacity beyond 2028 traffic forecasts.

ï Roundabouts have less Social/Environmental impacts because they reduce fuel consumption and harmful emissions by eliminating the idling of vehicles waiting at a red light.

ï Roundabouts provide similar pedestrian and emergency vehicle access as signals.

ï Roundabouts provide better business access due to the ease of making a u-turn at them.

ï The Roundabout alternative will cost less than the signalize alternative because the existing bridge can be reused even when the cost for the eventual reconstruction of the bridge is factored in.

ï Studies by the Insurance Institute for Highway Safety, Federal Highway Administration, and New York State DOT have shown that roundabouts reduce injury crashes by 75 percent. Multi-lane roundabouts have been shown to reduce total crashes by 8-37 percent.

4. If the roundabouts do not go in, what other options are available?

If roundabouts were not the preferred alternative, an alternative that included a raised median and traffic signals would be constructed. This alternative would be an improvement over existing conditions, however, once traffic volumes approached 2028 forecasts, congestion would return.

Another section of question and answers from Rogers will be printed in the next edition of the Forest Lake Times.

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