Bust open the Bottleneck with buses

Last Thursday I threw a post up on streets.mn that proved using mathematics! that the Hennepin-Lyndale Bottleneck is overbuilt as a roadway and could be reduced by a lane in most segments without risking more than moderate congestion. This result fits with my experience as a frequent user of the Bottleneck at rush hour over a period of many years – the freeway-scale design makes it feel like you’re inching through the facility at slug speed, but in reality traffic moves through the Bottleneck no slower than on other nearby urban streets. On top of the space that could be recaptured from the extraneous lanes, the existing lanes are mostly far too wide, so a lot of pavement can be reduced just by rebuilding the lanes at a more appropriate width.

Scroll down for pics!

So what to do with all this extra space? Anyone who glances over the last year or so of posts here, if still awake, can guess what I say: bus lanes. The thousands of bus riders that travel through the Bottleneck could be sped through daily and be insulated from occasional congestion, and those sitting in cars would watch as the buses made it through faster on this highly visible facility, encouraging them to think of transit as a better option. One of the great transportation weaknesses in Minneapolis is that the Devil’s Backbone (the ridge that comprises Lowry and Loring hills) creates a wall that makes it difficult to travel between Downtown and Uptown. It’s in the city’s best interest to encourage as much of that traffic as possible to take place on space-efficient travel modes such as mass transit.

Here is a map-like graphic I used on the streets post to show which segments could lose a lane without risking much congestion:


Most of the route along Hennepin is green, indicating that a lane can be removed, and the one segment that isn’t is just barely over the 75% threshold. This segment has an enormous amount of queuing space (650′ for the lanes coming from the Bottleneck and over 2000′ for the lane coming from I-94), so I’d suggest that here too a lane be removed and replaced with a bus lane. Here is a lane diagram of the Bottleneck with extraneous lanes removed and replaced with bus lanes where needed:


This provides a bus lane through the entire facility for buses coming to or from South Hennepin, and for much of the facility for Lyndale buses. The bus lanes would also be used for right turns indicated by standard lane symbols, which simply involves a switch from a solid while line to a dashed line shortly before the intersection, along with a right-turn symbol or two. I’ll reproduce an example from British Columbia here, because a lot of Minneapolitans seem to have difficulty picturing this:

The northbound segment just north of Franklin is more tricky, due to traffic exiting to I-94. The bus should still have priority, so I’d recommend striping a short lane for general traffic north of the intersection that is required to merge across the bus lane (yielding to buses in the process) before exiting:

HennepinAtFranklinNorthLegBusLanesThis may seem tight, but there is about 330′ or the length of a downtown block in which to accomplish this, which shouldn’t be a problem for traffic moving at urban speeds (20-25mph). I’ve depicted it within the existing curb-to-curb width, but as the northbound segment is being rebuilt as part of The Project, I’d suggest that the general traffic lanes be reduced to 10.5′ a pop, with the bus lane at 12′, so that it can be reduced 2′ overall and adjacent sidewalk/boulevard made a bit less pathetic/dismal.

As long as we’re discussing the above image, I’ll mention that it depicts the existing southbound roadway, the 34.5′ of which will not be touched as part of The Project. In this space I’ve ruthlessly slashed one of the general traffic lanes and replaced it with an offset bus lane. Additionally I portray the corner with a striped (and bollarded) curb extension, which should be added to every corner on a street with parking as the city’s adopted policy recommends.

It’s possible that something similar could be done on Lyndale at the north leg of the intersection with Franklin. The roadway there happens to be exactly the same width as Hennepin, and the traffic patterns seem to be mostly similar. I think that the city’s policy to reduce VMT is enough to justify replacing a lane in each direction with a bus lane, and additionally this area has been screaming for an extension of the Lyndale bikeway to Franklin (not to mention more pedestrian space, the lack of which forces an awkward dance at the southbound bus stop and taking turns in front of Rudolph’s). If this were to occur, here’s a suggested cross section:


However, there is a much higher volume of vehicles per lane on Lyndale than on the corresponding segment of Hennepin, and anyway this segment of the Bottleneck isn’t going to be rebuilt as part of The Project. It should still be restriped, though, to improve the currently awkward required movements and outrageously overwide lanes. Additionally, the Lyndale bikeway should be extended south by replacing the existing parking lane with a bollard-separated two-way cycle track. Here’s an idea for how this would look:

lyndale-ave-s-restriped-north-leg-at-franklinThis could also improve traffic flow by removing the scary merge of southbound traffic just north of the intersection (technically the traffic from I-94 is supposed to yield but they often don’t). It would do this by replacing one of the lanes of Bottleneck traffic with a bus lane, then giving each stream their own lane at the intersection and banning Bottleneck traffic from turning left (they have had plenty of opportunities to travel in that direction already). Here is a diagram:

SouthLyndaleRestripeLaneDiagramThis plan reduces capacity as measured by square feet of pavement, but I think it will actually improve traffic flow by reducing conflict points and increasing clarity about where to go (note how the northbound lanes now have one clear lane to get in that will take them either to Hennepin or to Lyndale & the freeways). I’ll point out that here too there is enormous queuing space, so dozens of cars could pile up (er, behind, not on top of each other) before impacting an intersection.

If you look back to my overall lane diagram above, there are a few other places where reducing a lane actually has the potential to aid the flow of traffic by making destination more clear. The southbound lanes are an example; currently the four lanes are ambiguous about which will go where, but if you cut a lane it’ll be one destination per lane, from left to right: 15th/I-94, Lyndale, Hennepin. The other spot improved by a lane reduction is the northbound lanes where it splits into Hennepin vs. Lyndale/freeways. Currently one of the lanes splits into both destinations, making the signage confusing. Since Hennepin downtown has been reduced to two lanes inbound, there’s absolutely no need for three lanes to split off the Bottleneck here, so I’d say do one general traffic lane to Hennepin that can be flared out to two at the intersection if necessary.

As you may have noticed, my plan mostly doesn’t actually reduce the number of lanes, but rather replaces some lanes with bus lanes. But there are many other changes needed along the Bottleneck, such as improving the space for bikes and peds and general greening, all of which requires space to do. Amazingly, the current lanes are so overbuilt that even assuming one of the current lanes in each direction is replaced with a 12′ bus lane, by reducing the remaining lanes to 10.5′ a substantial amount of space can be captured (zoom your eyes to the 4th & 5th columns from the right):

BottleneckLaneWidthsNote that each line of the chart indicates only one direction, so that for most of the segments, at least 10′ can be converted to bike/ped space or green buffers. Also, my analysis hasn’t even touched on the pointless “access” road between Groveland and Douglas, which could be eliminated altogether but at least could be substantially narrowed for a significant aesthetic improvement and public gathering space.

Public works has promised to release their latest design for the reconstruction at a public meeting on August 4th. I’m hopeful that they will use the space gained from narrowing lanes to separate the bike & ped streams along the Loring Bikeway, and my best case scenario is that one of the obviously superfluous lanes heading to Hennepin downtown will be dropped. But aside from that I don’t expect any substantial changes, in part because of Public Works’ continued auto-orientation but also because of the rumor I mentioned in the streets post that got so much attention in the comments. Rebuilding the Bottleneck substantially the same would be a tragedy for Minneapolis, not only because it dooms the city to decades more of unpleasant, auto-centric commutes but because it is a huge opportunity lost for a great central public space. If this occurs, rest assured I will expound on this rumor and call to account those responsible for the tragedy.

Postlude, because I really haven’t written enough yet: I of course think that the freeway ramp overpasses should be torn down and replaced with surface facilities like a roundabout or traffic circle, thus freeing up developable space as well as providing room for much greater pedestrian connectivity and cycletracks throughout. The plans shown here operate only within the constraints of the current reconstruction project, which do not allow us to ponder changing the freeway interchange, possibly with the ulterior motive of requiring their continued presence.