Alright folks. I went to the MDOT open house for the US-23 and M-17 improvement projects. What did I learn?
US-23 Improvement Project Study
MDOT wants to “improve” the US-23 corridor that divides Ann Arbor and Ypsilanti.
A quick lesson on induced demand
When you build a road, people build homes and businesses around it. When you increase the size of a road, more people will use it for their daily commute, and more businesses and homes will be built nearby since its a major corridor. If a corridor is congested, adding lanes is only a short-term solution. In the long term, congestion will return to its initial levels. This has been shown extensively in various studies. The only way to solve congestion is to eliminate car trips entirely. Not Just Bikes conveniently just released a video on this subject if you want to learn more.
The “Why?”
There is no concise goal in this project due to the sheer scope of what MDOT wants to do here. So we are just going to go through each aspect.
Reducing noise pollution
MDOT wants to add noise abatement walls along this corridor, which is a long-overdue update that is also needed on the I-94 corridor. Cars are a huge contributor to environmental noise. Anyone who has been to Matthaei Botanical Gardens will know that you can still hear US-23 despite being a mile away and surrounded by mostly forest. This is a great change and also limits future expansion of the lanes since the walls optimally need to be placed directly next to the road to be the most effective.
Adding a lane to “solve” congestion
- Flex lane – Because it is built in a shoulder, it bypasses federal requirements to conduct an environmental study. I have been told this is the only real reason MDOT wants to use a flex lane. That gives MDOT extra funds to add those fancy overhead signs…
- Additional general purpose lane – Obviously the worst option.
- HOV lane – Fine in theory. In practice, this will likely not be enforced. Make it a bus/taxi/rideshare only lane if anything…
- No rebuild – The obvious choice according to the traffic data
As mentioned in the Not Just Bikes video above, traffic planners often dramatically over-estimate the increase in traffic levels. The City of Ann Arbor intends to decrease vehicle miles traveled by 50% by 2030. The city is also looking at “reconfiguring all existing multilane roads under the City’s jurisdiction by 2030 for Council consideration as part of the FY2025 budget process.” Not only is there no current need for additional lanes under MDOT’s own criteria, but there will be even less of a need in the future.
Interchange redesigns
From a safety standpoint, this is needed. Both of these interchanges are dangerous to car drivers, and the M-17 interchange is practically impassable to pedestrians traveling on Washtenaw Ave. Lets take a look at each proposed option.
M-17 Interchange
- Rebuild – This interchange is a massive blemish on the area. It needs to be made more compact. There needs to be less conflict points on both M-17 and US-23 where lanes converge. Its bad for car drivers and pedestrians.
- PARCLO – Doesn’t solve the land use issue with the cloverleaf but reduces the number of conflict points where lanes converge. Would be somewhat safer for pedestrians on M-17 and substantially safer for cars.
- SPUI – The success of this interchange entirely depends on the exact implementation. This interchange is substantially smaller, opening up additional room for development along M-17. This interchange is also substantially safer for cars, but sometimes can be confusing. However a typical SPUI has multiple right turn slip lanes which would not improve pedestrian safety. These slip lanes would need to be changed into right turns.
- Diverging Diamond – A consideration that isn’t shown above. There is a somewhat negligible difference between a DD and SPUI when it comes to traffic flow. DDs are mildly more confusing for drivers. However DDs make extensive use of slip lanes, making them an inadequate solution for pedestrians.
Based on both City of Ann Arbor and the Washtenaw Ave PEL plans for the M-17 corridor, it could be argued that the interchange should be eliminated all together as this corridor will no longer serve as an artery. M-17 already is frequently backed up all the way to downtown Ann Arbor due to its lack of capacity, frequent traffic signals, and the perception that it is an artery when it is in fact a local business access route.
I-94 Interchange
Both proposals are bad because they require multiple lane changes within the interchange. Lane changes create traffic and conflict points, which is exactly the opposite of what MDOT is trying to solve. I don’t know why they are choosing to do this.
Infrastructure and safety improvements
MDOT wants to refurbish or replace aging and outdated infrastructure like bridges, which should be expected out of any Michigan road project.
M-17 / Washtenaw Ave PEL
Practical Alternative C: Business Access Transit (BAT) Lanes
I think this is the best of all the choices. You can go look at the rest of the options, but I am only going to discuss this one.
The bus lanes
The intention is that M-17 will no longer function as an arterial road for getting between Ann Arbor and Ypsilanti (it was never intended to do this). Instead, road users are expected to shift to using the highways instead. M-17 will be restored to a local access road to businesses and neighborhoods in Ypsilanti, as well as a high-speed throughway for busses, complete with transit priority traffic signals. AAATA aims for 5 minute bus intervals, which is frequent enough where you don’t need to check bus schedules before you walk out the door.
As for the bus lane itself, its actually not entirely a bus lane. I asked about how they intend for this to work and unfortunately the bus lane will still act as a turn lane for driveways and intersections. However it is still much better than no bus lane. In the future A2/Ypsi/AAATA could potentially copy DC and add traffic cameras aboard the bus that are used to ticket bus lane violations. Long term, Ann Arbor/AAATA wants to put in BRT along the A2 segment of this route, which may mean that the bus lanes will be moved to the center of the street.
The shared use paths
This design opts for 12ft wide off street shared use paths between Carpenter and Hewitt in lieu of painted and delineated bike gutters. I always prefer off-street shared use paths to dedicated on-street bike infrastructure, especially in this area given the highway interchange. 12ft is more than enough for MDOT (or if some local advocacy org 
) to stripe in bike lanes if they wanted to. I imagine these paths looking a lot like the ones in Oulu, Finland. In my mind, bike infrastructure should be at sidewalk level and should be buffered from the road by trees and grass, akin to the bike paths in the Netherlands. This makes the infrastructure safer and more comfortable. My measure of “is this safe?” is “would I let a child ride on this path unsupervised?” Additionally, the shared use paths will ensure that cars will be perpendicular to the path before crossing over it, reducing the chance they will cut someone off, granted MDOT doesn’t make the turning radii too large on the driveways and intersections.
Off street paths will also be better for year-round commuting. Because the shared use paths have green space on both sides, drainage is much better. If graded correctly, water won’t accumulate on the path and freeze into ice. There is also plenty of room for a full sized snow plow to push snow off the path and the street without impeding on each-other. Because regular full-size snow plows can be used, snow and slush tracks left by cars crossing the path can also be cleared more quickly and easily.
Overall consensus
The end result of Alternative C will still be sub-optimal. There are simply too many driveways crossing over the shared use path. However with well thought out zoning policies, over the next 20-40 years driveways can be consolidated and parking lots can be shrunk or eliminated. I think this sets up this corridor very nicely and would be an example for the rest of Washtenaw County.
Check out our new website!
You may notice that our newsletter looks a little different. That’s because we’ve moved our whole system over to our new website! We have archived all our previous newsletters onto the site so they are easy to find and browse. Our upcoming events are neatly listed on our event page. We will also be able to make dedicated pages or mini-sites for any future projects we peruse. More to come!
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