Mind The Gap: The Importance of Bridge Approaches

It goes without saying that bridges are important. No matter what mode your travel, bridges are often the only way to get across a river, train tracks, a giant freeway, or (in other parts of the world) a canyon or harbor or whatever. Paying special attention to bridge design makes sense. And in general, Minneapolis and Saint Paul have gotten better at designing bridges for bicycles, as bike lanes are now standard on new bridges. For example, Saint Paul’s new Hamline Avenue bridge over the train tracks and quasi-freeway will include a bike lane in each direction.

But bridge design is only half the battle. Equally important is how the bridge traffic connects at both ends. Bridge approaches are particularly difficult because bridges present unique design challenges for traffic flow. Bridges are almost always straight with zero intersections, which means car traffic will almost inevitably speed. (Thus each city’s notorious speed traps: the NE side of the Hennepin Avenue bridge in Minneapolis, or the North side of the Dale Street bridge in Saint Paul. Back in my driving days, I was caught at both.) Because of this, bridge entrances have the same problem as freeway onramps: they’re dangerous places where drivers have to change their expectations, moving from a high-speed low-conflict environment into a low-speed high-conflict environment. How you design that transition is very important.

One of the frustrations of bicycling through the Twin Cities is that too too many bridge approaches are medicore and unsafe, offering little continuity with the streets on either side. Often bridges will have useless bike lanes that connect to nothing, making a mockery of the “bike lane” concept. (For example, the bike lanes on both the North Dale Street and the new Hamline Avenue bridge connect to nothing.) Here are three examples of why bridge approaches can make all the difference.

[Note: these are mostly from Saint Paul because a) that’s where I live,  b) its “Saint Paul week” on streets.mn, and c) Minneapolis has been doing more to improve its bridges for bicycles.]

 

Wabasha Street Bridge

While downtown Saint Paul is notoriously lacking in bike lanes, its bridges are a bit better. Both the Smith Avenue (“high”) Bridge and the Wabasha Bridge are striped with bike lanes. The only problem is that they don’t connect to anything on either end. This is particularly frustrating on Wabasha bridge because the south end of Wabasha  Street has bike lanes only two blocks from the bridge terminus. There’s a 1/3 mile gap in the bike lane, forcing bicyclists to share the road with traffic for this short stretch. For bicyclists comfortable in traffic, most of the time this works fine, But every once in a while a car driver will try to pass bicyclists at extremely close distances, and for anyone who doesn’t like bicycling in traffic, this gap is a significant barrier.

(On the North end of the bridge, downtown Saint Paul doesn’t have any bike lanes at all. So there’s that.)

The solution here seems obvious. The traffic count on this part of Wabasha is a mere 12,000 cars / day. The city could simply continue the 3-lane + bikes configuration up to the bridgehead for the cost of some paint without perceptibly impacting traffic flows.

 

 

Lake Street / Marshall Avenue Bridge

This bridge is one of the most important in the city, connecting Minneapolis and Saint Paul at the hip. Unfortunately, its bridge approaches are medicore. On the East Side, Marshall Avenue has a similar situation to the Wabasha. A bike lane runs along Marshall Avenue for miles, only to stop short 1/3 of a mile before the bridge. This forces bicyclists to share the road with cars speeding down the hill for a tiny stretch before reaching the bridge’s bike lane.

On the other side, reaching the river road’s bike lane involves a strange do-si-do with a island median. The interchange between teh lovely river road bike lanes and the bridge forces you to either travel the wrong way down an onramp or jump a curb. Heading the other direction, there’s an almost blind intersection where cars come speeding up a hill under the Lake Street bridge.

Easy solutions exist for both sides. On the East Side, you simply continue the bike lane for the last 1/3 of a mile, again needing only a little bit of paint. Traffic counts are a bit higher (17,500 cars / day), but this is the city’s #1 bike lane intersection. On the Minneapolis side, you would have to install a stop sign on the river road and remove a bit of concrete to connect more smoothly with the bike path.

Franklin Avenue Bridge

Not long ago, the Franklin Avenue would have made this list. On the West side, Franklin’s bike lanes disappeared before you reached the bridge. On the East side, the intersection with the river road, Franklin Avenue, and the bike paths toward the University campus were impossibly confusing for all users.

Today, this bridge shows what a difference good approaches can make to create a continuous, relaxing bicycle trip. The city removed a traffic lane in each direction and installed bike boxes to make sure that bicyclists were given space and visibility at the challenging intersection on the East end. The city’s 2012 bike and ped counts saw 3,000 people crossing this bridge each day.

So what?

Bridge approaches matter because small gaps in the bicycle infrastructure can have huge impacts. Even if 90% of your bicycle trip is safe, convenient, and comfortable, if the other 10% of the trip involves a harrowing gauntlet of speeding cars, many people will leave their bicycles in the garage.

These gaps might not seem like a big deal when viewed on a map, but they are very important if Minneapolis and Saint Paul want to follow through on “completing the streets” and creating bicycle facilities that work for everyone. There are a lot more bridges I could add to this list, places that become huge physical and psychological gaps in the bike system. Washington Avenue over the freeway, Broadway Avenue, Robert Street. At the same time, there is a lot of progress. For example, the new Lowry Avenue bridge is done well.

I’ve ridden down Marshall Avenue toward the Lake Street bridge probably hundreds of times, and usually the spot where the bike lane ends is no problem. You are travelling down the hill at a good clip, and cars usually give you room, moving over to the left lane. I typically “take the lane,” positioning myself just right of center. But once last summer, as I headed down the hill I heard a horn honking in the distance behind me, repeating over and over. I had no idea what it was. About halfway down the hill, the horn kept getting louder, and all at once, a red pickup buzzed past me, just an inch from my left shoulder. I was right next to the “bikes may take full lane” sign, and it was probably the closest I’ve come to being run over by a car. I was a few hundred feet from a bike lane in either direction, but as the truck sped across the bridge in front of me I became completely distraught. It took me a while to calm down again once I’d reached my office.

Experiences like mine are why bridge approaches need to be done carefully. A bike lane on a bridge is almost useless if it doesn’t connect to anything, or if the approach is dangerous and doesn’t address speeding cars. At the same time, you can’t go out of your way to avoid bridges. By definition, they’re choke points for all modes of traffic. Particularly for  bicycle trips, paying attention to these gaps can make all the difference.