The slide on travel patterns is interesting. Given that trips are short, including many downtown-to-downtown, and drivers have a strong preference for other routes when using as a bypass, it seems like a grade-separated motorway is pretty poorly-suited to the corridor and isn't very successful in its objectives.
If people are bypassing the bypass, it really calls into question why it's there in the first place. Unless there's a more concrete argument than "it would be disruptive in the short-term to change it," we should really put freeway removal on the table instead of the comparatively expensive, challenging, slow, and less locally-beneficial cap option.
Could you further explain your thoughts here? I'm not following. Just to be clear, I mean this out of curiosity and not as snark.
For sure. The idea behind grade-separated highways is to put all the through-traffic (traffic that isn't stopping locally) in one place, to make it easier to travel long distances uninterrupted, and to enable high-speed travel. The travel patterns suggest that through-traffic drivers strongly prefer 694--that is, the people this thing was built to serve aren't actually using it.
There's also a surprisingly large amount of intraurban
usage on the corridor--people going between the downtowns, people going a couple miles in St. Paul, and so on. A grade-separated highway does not serve this kind of traffic very well: the high speeds give little or no benefit when you're only traveling a couple miles and most of your trip time is spent navigating to/from the bypass and merging/exiting, access to destinations is more complicated, and transit is slow and difficult to access (despite serving an unusually transit-dependent population). We have lots of better street designs for arterial urban roads--boulevards, transitways, etc. These offer better integration with neighborhoods, are safer, are less prone to congestion, are cheaper to maintain, don't have the barrier effect on the surrounding communities, and support transit much better.
Light rail lines down the middle of highways are typically a bad idea.
Just think about the added issues that using a highway ROW brings for transit riders:
- Stations are further away from homes, businesses, and other destinations
- Accessing a station requires walking across a highway bridge and safely navigating highway entrance/exit ramps
- Accessing a station requires walking up or down stairs or using an elevator
- Waiting at a station is unpleasant and unhealthy because of the incredible sound generated by a highway
- Waiting at a station is unpleasant and unhealthy because of the incredible amount of noxious gases generated by a highway
Obviously you can mitigate these issues to varying degrees, but why would you bother if there is an alternative?
I actually had pretty positive experiences using BART (which has many of these kinds of stations) when I lived in the Bay Area. The grade-separated right-of-way is a huge
benefit for reliability and travel time, and the only other way to realize these benefits is a subway (which is an order of magnitude more expensive). Having a dedicated ROW with no crossings basically just waiting to be built on is a pretty big deal.
Bridges can be reasonably enclosed and well-connected to their environment, and stations can be staggered with on/offramps to avoid dangerous crossings. And of course, if it's being considered in the context of freeway lids, the lids themselves address many of the issues like integration with the neighborhood (distance from destinations, unpleasant bridges, and so on).
That's not to dismiss your valid concerns; it's just to suggest it's a tradeoff that does have some significant upsides as well.