Thursday, September 04, 2008

Creative Traffic

This summer has seen a lot of roadbuilding activity in Tartu, including some of the busiest intersections. The first one to be comprehensively rearranged was the traffic circle at the end of Riia, a thoroughfare used by town traffic, shoppers headed for the nearby mall (there is really a ridiculous amount of them in Tartu), and commuters from the counties to the south. Whereas previously the traffic arrangement on the Riia Ring consisted of gunning it and hoping for the best, the new solution involves abundant directions on which lane goes where. There is a strong priority for people going from downtown to the mall and back, which has made the circle a lot more efficient. A few hundred meters away is the Aardla cicrle, which has heavily rebuilt to allow people to turn right without ever getting in the way of the other cars.

This sort of creative traffic management has now made its way to the other major hubs of Tartu traffic, and when combined with the apparent lack of foresight and coordination (which I'm sure Mingus will be happy to discuss with you at length), it has resulted in some very odd patterns.

The Sõpruse circle is definitely one of Tartu's busiest intersections, since almost every bit of traffic headed to the Annelinn bedroom community has to go through it. Over the summer, bits of it were closed off for major alterations. City planners attempted to surgically separate particular traffic flows and direct them down separate paths, wherever possible - but they didn't have the money for a multi-level cloverleaf like the one that has sprung up in Riga. So now you can turn both onto and off the bridge, making right turns, via dedicated lanes - so dedicated they are actually physically separated from the ones joining the circular traffic. And those, too, are separated from each other just before the circle.

It's confusing at the best of times, but some plausible manouvers have become downright dangerous. If I'm coming off the bridge and want to get to the Eeden mall (yes, there is a mall at every intersection in Tartu), I can either take the back road that leads to Ihaste, the slipway up to the top floor of Eeden's parking lot, the turnoff to the bottom floor, or either of two physically separated lanes that turn right onto Kalda tee - one that bypasses the circle traffic, and one that cuts through it.

On the face of it, this isn't too bad - a lot of people want to turn right off the bridge on weekday nights, and the tailbacks used to be stupendous. But there are at least two manouvers that have been made a lot more dangerous by this new arrangement. First, if I want to exit either the bottom floor of the Eeden parking lot or the Neste gas station, and join the circle, I have to completely across three lanes of cars flying off the bridge at the better part of 70 km/h, and then make a sharp 90 degree turn at the last second - I can't cut the corner because otherwise I will clip the safety island that separates the leftmost lane from the next one. And a lot of people want to do this: the other way of getting out of Eeden involves circling behind the big construction store next to it (yes, Tartu is a hotbed of consumption, deal with it). Or you could take your chances doing a U-turn on Kalda tee - which requires both practice and a car with a pretty tight turning radius.

The other dangerous manouver is if I want to go into either Eeden or the gas station while coming off the circle, from any direction except the bridge. Two lanes come off the circle onto Kalda tee, but there is another lane immediately to the right, the separate one off the bridge. The turn-in for Eeden and Neste is right there. I have to swerve rapidly to the right, cutting across the path of the people happily accelerating through the awesome new separate lane.

There's a similar trick with the entrance to the new Tasku mall's parking lot. It's a slipway just before the other busy car bridge in Tartu, and there is a right turn from Turu street onto the bridge. The streetlight pattern won't let you turn right from Turu at the same time as the main traffic flow from Riia, but you are indeed supposed to merge at the same time as the left-turn crowd from the direction of the new Kaubamaja. How long before two cars decide to occupy the same physical space in front of the Tasku parking slipway?

There is more odd traffic management elsewhere. There are now two lanes to turn left from the Riia bridge onto Turu; very useful at relieving a perpetual tailback, but they did it without widening the road, instead making all the lanes narrower. So now a bus or lorry just barely fits into a lane. I'm sure they will end up clipping other vehicles sooner rather than later. On Narva mnt, turning left from Raatuse, the road markings tell you to make a sharp 90-degree turn in the inner lane, instead of cutting the corner along a completely unused patch of asphalt (which everyone does, anyway).

Did anyone think this through properly?


Juhan said...

I've developed a perverse liking to all of those weird solutions. However I am furious at the city authorities since they were obviously too mean to build proper bridges/tunnels for pedestrians by the Sõpruse circle.

Kristopher said...

Far be it for me to request images in a blog, but a little applet/video game would be great to visualize and practise those manoeuvres.

Ain Kendra said...

Wips has already tried to analyze this Sõpruse bridge case.
See: if interested.

While also in other countries shopping centres and various service units (gas station etc) are located close to junctions and bridges, the community has first voice on planning. We see always problems where landowners are the planners trying to maximize the profits and what's the craziest - after junctions and bridges are designed and built, coming up with ideas on land use. Usually these issues are processed before design phase.


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