Another new report details how bad Seattle drivers are. And that's one part of the problem with the 9th worst traffic in the nation (for 2018) when the city itself is only the 22nd biggest city in the country.
But along with bad drivers, Seattle is plagued by a history of imbecilic freeway engineers. Their biggest sin for the I-5 corridor through Seattle is a series of on and off-ramps that are on completely opposite sides of the freeway. There are way too many merges between Mercer Street in the South Lake Union area to the 45th and 50th Street exits on the north side of the Ship Canal Bridge on I-5 that require a driver to cross all lanes of traffic to get to the intended ramp.
These merges and exits are killing traffic in Seattle.
If you want a low cost way to improve traffic flow in Seattle, it's time to close some off-ramps.
It doesn't take much money to close an off-ramp. A few crews to install some jersey barriers and the traffic healing can begin. Start by closing the southbound I-5 ramp at NE 45th street. This on-ramp is generally too short to allow most drivers (let alone buses or trucks) to accelerate up to speed to merge with traffic when there's no gridlock over the Ship Canal Bridge. But the NE 45th Street on-ramp is also problematic because so many drivers take that on-ramp to reach eastbound Highway 520 which requires the complete merge across all lanes of traffic over the length of the Ship Canal Bridge. All that merging plugs traffic.
A better plan would be to re-route southbound I-5 traffic to the NE 50th Street on-ramp. Then you only have one on-ramp in that approach to the Ship Canal Bridge. Granted there will be more traffic congestion on NE 50th street but the goal of this exercise is to reduce congestion on I-5. If you really want to reduce congestion in this area approaching the Ship Canal Bridge, there is another change to consider. Re-route all cars aiming for the eastbound Highway 520 exit to the Ravenna on-ramp. Admittedly this does require a circuitous route from Wallingford or the U-District neighborhoods, but it would start those vehicles seeking to reach the eastbound Highway 520 exit in the left hand lane of traffic (where the 520 ramp is already located) and further reduce merging.
Another on-ramp to close is southbound I-5 at Boylston. This, too, is a short on-ramp which doesn't allow cars to get up to speed when there's no traffic congestion and its compounded by the vehicles on this ramp immediately entering into the exit-only lane for Mercer Street in the southbound direction. That means virtually every car that goes down that ramp has to immediately merge over another lane to avoid the Mercer Street off-ramp. More merging means more slowing (plus if you're in the Eastlake neighborhood and you need to drive southbound to South Lake Union or downtown, just do us all a favor and take the surface streets). Close this ramp and force drivers to go southbound along Lakeview Boulevard to Eastlake Avenue (by the Pemco and REI buildings). Those cars can then funnel down to the Yale Avenue on-ramp.
The same concept applies to the examples above from the U-District and Wallingford neighborhoods: reduce congestion on I-5 but it will mean more congestion on some of the surrounding surface streets.
Lastly, in the southbound direction, close the Union Street off-ramp at the Convention Center. Closing this off-ramp will reduce another big merge problem as cars from the Yale Street on-ramp (south of the Denny Way overpass crossing) enter I-5 and immediately want to merge left to reach I-90 or continue on southbound I-5. For tour buses (heading to the Convention Center) and cars wanting to exit at Union Street, just force those vehicles down to the James Street exit and have them re-direct north on 4th Avenue. It will add more time to their trip to the Convention Center (and mid-downtown Seattle) but it will be completely worth it to improve traffic flow southbound I-5 underneath the Convention Center.
Here's another low (really low) cost thing to do to improve traffic flow southbound I-5 under the Convention Center: change the over-head freeway sign that says 'I-90/Spokane/Bellevue Exit Only'. This sign falsely implies that southbound I-5 traffic will not go through (which it actually does). By changing this "exit only" sign to include "southbound I-5 OK/access" it will give drivers the option of proceeding southbound without hastily merging one more lane, which again creates the infuriating gridlock underneath the Convention Center. SIDEBAR: using the I-90 collector/distributor off of southbound I-5 to continue on southbound I-5 can be very congested when all the lanes merge back together at the sports stadia, but this signage change would at least let drivers know they have some options to proceed southbound I-5 without inducing another last second merge at I-90.
Obviously I-5 through Seattle needs some wholesale changes to improve traffic congestion. All that would cost billions of dollars (at least in this state, anyway) to realign the mess of incompatible on and off ramps to properly correct the alignment from I-90 to the Ship Canal Bridge, but these suggestions are very low cost. They would immediately improve traffic flow by reducing three stretches of multi-lane merging. Less merging equals faster traffic flow.
All it would cost is the time for crews to put up a few signs regarding the changes, re-striping some road lanes and putting up some jersey barriers to block these ramps. This could be done for several-hundred thousand dollars. Even in a world of public works (transportation project) cost over-runs, it would be difficult to spend $1 million to make the above fixes. Imagine spending $1 million to shave 10, 20 or 30 minutes a day off of I-5 commute times through this 4-5 mile stretch in Seattle (again this is for vehicles already on I-5, not for drivers on surface streets entering the freeway to reach their desired location).
Now, will anyone in Seattle, King County or Olympia politics have the vision and spine to implement any of these simple, low cost ideas? Don't hold your breath. All of those so-called leaders are invested (heavily) in making Seattle traffic as bad as possible.