Friday, April 10, 2015

A Solution for the Commercial-Liberty Dysfunction Junction?

What to do about the split at Alice and Fairview where Commercial divides and dual turn lanes morph into southbound Liberty Road?

The Commercial Vista Corridor study might have an answer.

The two lanes of Liberty are treacherous to cross
The bike lane is striped here, and it looks like you should attempt a crossing of the two new lanes that turn across your path and become Liberty.

This is intuitive, and many people on bike attempt it. They hide in the bike lane, wait for a break in the traffic, and scamper. We'll call this the "hide and scamper" move.

Scary, but intuitive and direct: Hide, then scamper
City Traffic Camera, Commercial at Fairview
The preferred alternative has been a very lightly signed - probably invisibly signed! - and greatly enlarged jug-handle turn.

Left turn signed at Liberty and Vista, 2009
Stay in the right hand bike lane, and at Office Depot use the crosswalk to turn left, get into traffic on Vista, and them make a right-hand turn to rejoin the bike lane on Commercial. (Indicated by #1 on map below.)

From the "Draft Transportation Issues Booklet"
and the "opportunities" map
Back in 2009, the Vision 2020 group also looked at this intersection, and the preferred solution was to give people on bike a leading interval during which auto traffic would be stopped, giving them enough time safely to maneuver across the dual turn lanes and back to the bike lane.

Vision 2020, December 2009
The red arrows here show stopped traffic, the green arrows show moving traffic, and the green dots the bicycle movement.

Vision 2020, December 2009
At the time, the hope was is to find a solution that could be slid in to become part of the work under the road bond.

Multiple solutions ranked, Vision 2020, December 2009
We missed that badly.

Then there was Bike and Walk Salem.  That still didn't result in a solution.

And now we have a third attempt at a solution.

Summary from Recommendations booklet
There are three proposed alternatives in the draft recommendations.
  • A bike box at Alice on Commercial
  • Jug-handle turn 1: A bike box at Vista (Office Depot)
  • Jug-handle turn 2: A bike phase during traffic signal cycle at Vista and Liberty
(Note that the jug-handle approach ranked #6 in the 2009 discussion.)

From the more detailed recommendations memo...

On the bike box at Alice:
When a red light for the southbound movement at the Alice Avenue intersection is displayed, bicyclists could move into the bike box once they reach the intersection and wait in the designated bicycle area in front of the motor vehicles. Once the traffic signal turns green for the southbound movement, bicyclists are already ahead of the motor vehicle traffic, thus, resulting in a safer transition southbound on Commercial Street. If the bicyclists arrive on a green light, they will either have to continue southbound travel with through motor vehicle traffic similar to existing conditions or wait for the southbound red light phase to utilize the bike box and get in front of motor vehicle traffic. The bicycle box option may result in a minor intersection delay due to the reduced saturated flow but future 2035 analysis indicated that this small delay is not anticipated to significantly degrade intersection operations.
On Jug-handle 1:
A bike box could also be implemented at the Vista Avenue/Liberty Road intersection which would require southbound bicyclists to travel along Liberty Road through the “Split” to Vista Avenue. Once at Vista Avenue, the bicyclists would travel to the bike box on the west leg of the intersection (in front of Office Depot) and wait until the eastbound phase is allowed to move through the intersection. This option would require Vista Avenue to be widened between Liberty Road and Commercial Street for eastbound bike lanes as well as additional right-of-way to accommodate the bike box entry.
On Jug-handle 2:
The bicycle phase at Vista Avenue option requires southbound bicyclists to travel along Liberty Road through the “Split” to Vista Avenue. Once at Vista Avenue, the bicyclists will activate a detector and utilize a bicycle-only phase that will allow them to travel eastbound through the intersection onto Vista Avenue and turn right at Commercial Street to continue southbound. The addition of a bicycle-only phase at the Vista Avenue/Liberty Road intersection would reduce green times for motor vehicle movements however future 2035 analysis indicates that a bicycle phase at this location would still result in the intersection meeting the City of Salem’s mobility standards in the year 2035. This option would require Vista Avenue to be widened between Liberty Road and Commercial Street for westbound bike lanes as well additional right-of-way for the Liberty Road/Vista approach.
Notice in two of them how our commitment to hydraulic autoism introduces the possibility that "small delay" could "degrade intersection operations" and fail to meet "City of Salem’s mobility standards in the year 2035."

Never mind that the intersection already badly fails any plausible mobility standard for any user group other than those in automobiles!

(Our analysis here may also be complicated by the fact that the Feds consider this intersection part of the "National Highway System" and that's an additional layer of commitment to hydraulic autoism. Until we develop and formalize evaluations for multi-modal and lower-carbon levels of service, we will be in thrall to antiquated Eisenhower-era standards for autoist mobility.)

From here it seems like a combination of the bike box at Alice + either one of the jug-handle turns is most desirable. "Strong and fearless" cyclists could use the bike box at Alice to continue south; others could use the jug-handle at Vista. These solutions still don't really serve kids and families, but they would be an incremental solution. One problem with the bike box at Alice is that, per the 2009 proposal, it would benefit from the addition of a leading interval when people on bike can proceed, but car traffic remains stopped.

Just implementing one only, either the bike box at Alice or one of the jug-handle turns, is likely to result in lots of free-lancing - the bicycle "anarchy" and "urban deers" that autoists lament and even get hostile about. If the signed movements aren't intuitive and direct, compliance will be low. One reason orderly bicycling isn't universal is because we saddle people on bike with crappy, dangerous conditions like at this intersection. So of course people improvise with non-standard movements.

Hopefully a commitment to a design solution will emerge from the study and get into the queue for funding.

There will be an open house on the 23rd.

For all notes on the Commercial Vista Corridor Study see here.


Anonymous said...

I would be content with green bike lane transitioning across the two turn lanes like we now have at Glen Creek approaching Wallace. Since we are obviously abandoning the " interested but concerned" let's get something that at least helps the "enthused and confident".

Anonymous said...

Without the leading bike interval, the bike box seems to offer little to no help at all. I have never seen a bike box used in this way. Typically, they are used to prevent right hooks in dense, urban settings and not to cross fast moving traffic on a suburban arterial. The "jug handle" options are just silly. There is no good reason for prescribing unnecessary out of direction travel (through additional intersection) for one user group.

Anonymous said...

PSU students from SCI also looked at this tricky intersection in fall 2010.

Pages 24-29.

Salem Breakfast on Bikes said...

Thanks! Forgot about that.

The drawings and concepts they analyzed look like they draw largely on the Vision 2020 concepts.

There were two student teams, and the recommendation from the second one:

"Based on the analysis results, we recommend the Bike Box Approach. The Vista Approach did provide a slightly lower traffic delay and may appear to be the best approach based solely upon the data. But the Vista Approach is similar to the current configuration, which is not meeting the City’s needs. If the Vista Approach were implemented, the majority of cyclists would continue to bypass Vista Avenue and merge into vehicle traffic in order to remain on Commercial Street. Also, Vista Avenue does not have a bike lane at this time. Adding a bike lane on Vista Avenue would require the purchase of a right-of-way.

The Bike Box Approach is a safe method for moving bicycle traffic across two lanes of vehicular traffic to continue southbound on Commercial Street. This method works best when the bicycle arrives at the intersection during a red light. To help facilitate this movement, we recommend a light be installed for bicycle traffic only. The light would remain red until a bicyclist came through the bike lane. The bike would trip an induction wire which would send the bicycle light into the traffic queue. Once the vehicle signals were red, the bicycle light would turn green, giving cyclists a head start to safely clear the intersection. Due to the light bicycle traffic (15 per hour), this approach will offer a minimal overall delay

Anonymous said...

But no "bike only" signal is being proposed in this study. Is that correct or did I miss something?

It is very rare to have a red light at Fairview due to S. Commercial traffic being prioritized so the bike box would rarely get used. It would essentially function how it does now. "Merge and pray" is what I call it.

The Glen Creek style green lane would at least offer some help. I can't see if it was even considered. Yet it just seemed to appear at Glen Creek (without a major study).

Salem Breakfast on Bikes said...

Anon - yes, I think the fear of "small delay" at the moment keeps a leading interval and/or bike signal out of the "bike box" option here.