The flex posts at Miller Avenue and Montford Avenue/La Goma Street went down on Monday, August 3. Three months from that date falls in the first days of November, so the pilot is now close to its review. The City of Mill Valley has said it will evaluate the project after three months and then recommend keeping it, revising it, or removing it.
Most of the talk about the intersection asks whether the new layout "works." The council asked a narrower question when it approved the pilot. It accepted a known cost in time in return for an intersection with fewer things to watch. And the permanent fix on the horizon is funded only for design work so far, so the version you drive through this week may be the one Mill Valley lives with for longer than three months.
Eleven Seconds, Priced In Before the Paint Went Down
City Council approved the pilot unanimously on July 29. Mill Valley Briefing reported that it converts the dedicated left-turn lanes on both Miller approaches into protected pedestrian buffers marked with flex posts and bollards. Drivers can still turn left from either direction. They now do it from the shared lane next to the old turn pocket, and that lane also carries through traffic.
Here is what changed at the corner, drawn from the city's materials and the Briefing's account of the council meeting:
| Before August 3 | Under the pilot | |
|---|---|---|
| Left turns from Miller | Dedicated turn pocket | Shared through/left lane |
| Pedestrian crossing | Full width of car lanes | One fewer car lane, wider median refuge |
| Bike lanes | Standard markings | Buffered lanes, markings extended through the intersection |
| Weekday evening peak wait | About 17 seconds on average | About 28 seconds projected |
The bottom row is the cost. Senior Project Manager John Brencic told council the redesign was projected to add about 11 seconds to the average wait during the weekday evening peak. He said most of that delay would land on Miller Avenue, with less on the side streets. The city's own survey page says the same thing more plainly: "Although a safety improvement, this modification may add travel time to trips along Miller Avenue."
So if the wait at the corner feels longer this fall, that is the result the city projected before the paint went down.
Why This Corner, and Why Not a Signal
The intersection got this treatment because of the 2025/2026 Miller Avenue Corridor Intersection Safety Study. Consultant Kittelson & Associates reviewed crossings from Almonte Boulevard to Millwood Street. The designs went through a public open house on December 4, 2025, the Transportation and Mobility Advisory Committee on March 23, 2026, and the Traffic Safety Committee on April 15, 2026. Montford/La Goma came out of that process as the highest priority. The Mill Valley Chamber of Commerce's project summary lays out that sequence, and the city keeps the full corridor study online.
The study counted 31 crashes at the intersection between 2015 and 2024, and broadside collisions were the most common type. That figure needs a baseline. Councilmember Stephen Burke estimated, and staff confirmed, that roughly 73 million trips have passed through the intersection since 2015. Burke described the problem as "less about volume and more about driver behavior." The Briefing also checked the state's crash reporting system and found the intersection ranks 21st in Marin County for single-intersection crashes over the past decade. It pointed out that this ranking counts raw crashes and does not adjust for traffic volume.
The obvious fixes had already been ruled out:
- A full traffic signal. The intersection's layout doesn't allow left turns off the side streets to run during a signal phase without conflicts. Staff said changing the signal timing to handle that would defeat the purpose.
- Restricting through traffic from Montford and La Goma. Police and Fire advised against it because of delays in emergency response.
That left the turn pockets. Removing them gives pedestrians one fewer lane to cross, reduces conflicts, and makes it easier to see who has the right of way. Brencic summed up the goal at the meeting: "Less crashes, less confusion."
Councilmember Urban Carmel described the deal openly, as the Briefing reported:
"The reward is going to be better safety, we hope. The cost is a delay. And we need to clearly communicate that it's going to be a delay, but it becomes a more clear intersection."
He also set the exit condition: "If this is a disaster, let's pull the plug."
What the Three-Month Mark Actually Decides
The pass/fail test for this pilot is not a shorter commute. The delay was assumed going in. The review asks whether the corner is clearer and safer enough to justify that delay, and the city is building the answer in a set order:
- Before data is already collected. Pre-implementation counts came from the corridor safety study.
- After data comes from at least three months of the new striping. Kittelson was also scheduled to be on site in the first few days to watch the new traffic patterns, and the city said the turn lanes could be restored quickly if an obvious safety problem showed up.
- Resident opinion runs through a city survey. The Miller & Montford/La Goma Intersection Pilot Program Survey asks whether respondents knew about the pilot and how often they travel through the intersection.
- Staff recommends keep, revise, or remove. If the data isn't conclusive, staff told council they would come back to ask for a three-month extension.
- Council hears the results. The Chamber's summary puts that in late 2026 or early 2027.
Early November is when the measurement window closes. The decision comes later, and an extension would add another three months before it.
Vice Mayor Caroline Joachim raised two concerns at approval. One was emergency access. Staff answered that fire apparatus can drive into the bike lane or the old turn pocket and over the flex posts, which aren't rigid. Her other concern was timing: "My concern is that we're rolling out this pilot program before school... I don't know how many people know this is coming." That explains the survey's first question, which asks whether you were aware of the pilot at all.
The Permanent Version Is Funded for Drawings
The longer-term option on the table is a single-lane roundabout. Its central island would be mountable so buses can drive over it. On September 28, Mill Valley Briefing reported that the Transportation Authority of Marin was on track to fund $453,000 of the city's $2.5 million request to rebuild the intersection. That figure comes from the city's application in TAM's September 16 committee packet. It would pay for design work, not construction.
TAM staff ranked Mill Valley's application last of the nine Marin projects in this round of federal funding. By comparison, San Rafael's Canal Crossing Project ranked second and is recommended for its full $5 million request. Marin Transit's bus facility electrification project ranked fourth and is recommended for $4 million.
Carmel sits on the five-member TAM executive committee that decides the funding. "$450,000 is better than zero. It gets us going," he told the Briefing. He said he hopes to raise Mill Valley's share before the vote and needs two of the other four commissioners to back him. As of that report the vote had not taken place, so the amount could still change.
Put the two timelines side by side. The pilot's results go to council around the turn of the year. The roundabout, at the funding level now recommended, would get a design and no money to build it. If council keeps or revises the pilot, the flex posts become the stopgap until something permanent can be paid for, and a stopgap like that can stay in place for a long time.
The practical effect for anyone who drives Miller at the evening peak is a wait of about 28 seconds instead of about 17, which is what the city projected. Pedestrians cross one fewer lane, and cyclists ride buffered lanes through the corner. Once Kittelson's three months of data are in, council will decide whether that trade holds.
If you own a house on one of the streets that feed into Miller and want to talk through how changes like this one fit into your home's long-term picture, Bonnie Spindler has spent more than 30 years helping Bay Area owners understand how the blocks around their homes change over time. Book an Appointment and bring your questions.
