"Any improvement to mainline flow is achieved at the cost of increased delay to left turning and side street traffic." That sentence comes from Caltrans' own June 24, 2026 evaluation of the adaptive signals on Highway 68. It describes the corridor as it has run since spring. Through traffic between Salinas and Monterey moves a little faster. The cost of that speed lands on the people turning onto the highway from Corral de Tierra Road, San Benancio Road and Laureles Grade.
Those same three intersections are where the Transportation Agency for Monterey County wants to build its first roundabouts. The state deadline for the funding application that would pay for that work is November 19.
What the Signals Were Built to Do
Caltrans switched nine Highway 68 signals to adaptive control on Monday, May 4, 2026. TAMC's project page lists the date as May 5. The system uses Miovision technology and adjusts green time to the traffic it detects. It does not rely on fixed cycles.
On the highway itself, the change is measurable. The June 24 Caltrans and TAMC evaluation compared the week of April 6–10 with the week of May 11–15. Over that stretch:
- Westbound delay in the morning peak fell from 61.96 to 56.79 seconds per vehicle, a gain of about five seconds.
- Eastbound delay in the evening peak fell from 60.38 to 54.32 seconds, about six seconds.
- Side-street delay rose in both peaks. Mornings went from 55.43 to 65.63 seconds, and evenings went from 46.25 to 74.12 seconds.
So the mainline gained five or six seconds while the evening side-street wait grew by almost 28. The system did what it was built to do. It moved the delay off the highway, and most of it ended up on the side roads.
Where the Green Time Came From
TAMC's August 26 board presentation ran a longer comparison. It set the morning peak hour from March 26 to April 30 against the adaptive period from May 28 to July 30, one intersection at a time.
| Intersection | Change in side-street delay, AM peak, summer 2026 |
|---|---|
| Olmsted Rd | +19% |
| Canyon Del Rey Blvd | +10% |
| Ragsdale Dr | +25% |
| York Rd / Boots Rd | +52% |
| Pasadera Dr | −20% |
| Laureles Grade | +33% |
| Corral de Tierra Rd | +55% |
| San Benancio Rd | +23% |
The Corral de Tierra side street had the largest increase on the corridor. York Road came close behind. Laureles Grade and San Benancio also rose by double digits. Pasadera was the only intersection where waiting to turn got shorter.
"Adaptive signal control improves mainline performance by reallocating green time to the primary corridor. As a result, side-street vehicles experience higher median delays during the peak hours," the August slide reads. The traffic waiting at the eastern intersections comes from the neighborhoods behind them. Corral de Tierra Road serves the Corral de Tierra valley. San Benancio Road serves the canyon. Laureles Grade is the route over the hill to Carmel Valley.
These figures are the latest TAMC has published, and the data ends July 30. They describe a summer without school traffic. They don't show how the system has handled October mornings.
The Complaints Point the Same Way
The public feedback matches the traffic counts. The August 26 presentation reported 25 complaints about the signal pilot in 2026. Twenty were about side-street or left-turn delay. Two arrived in July, when school was out, and one had come in during August as of August 19.
The June evaluation also explained what happens after a complaint is filed. The Caltrans maintenance crew assigned to this corridor "does not have the expertise to manage/troubleshoot new signal control." So every operational complaint goes to Traffic Operations Engineers in San Luis Obispo. The same document said Miovision's data was still under review because of "erratic traffic counts observed during May and June." The before-and-after numbers above came with that caveat.
Why the Same Three Corners Are Getting Roundabouts
Phase 1 of the Scenic State Route 68 Corridor Improvement Project covers San Benancio Road, Corral de Tierra Road and Laureles Grade. TAMC's case for those three intersections rests on the trade-off already in the data.
"There's always been a trade-off between pushing more traffic along Highway 68 and holding up the traffic on the side," TAMC principal engineer Doug Bilse told KSBW in June. He said preliminary data showed roundabouts would move "significantly more traffic than a traffic signal" and that "the side streets will get served a lot more efficiently." A signal has to take green time from one direction to give it to another. A roundabout lets traffic from every approach take turns entering. TAMC is betting that the side-street wait is a limit of signals in general, not of this particular signal system.
At the August 26 meeting, Ryan Caldera of Caltrans said the Phase 1 analysis was rerun using the adaptive signals as the starting point. That way the roundabouts were measured against the improved corridor, not the old one. He said the analysis still shows the roundabouts improving safety and traffic flow. He also said they are projected to reduce the potential for serious-injury and fatal collisions by simplifying the movements through each intersection and lowering speeds. TAMC's presentation that day called the adaptive signals an "effective short-term improvement" and the roundabouts the "long-term solution for mobility, safety, and resilience."
Caltrans also lays out the safety need on its project page. Rear-end collisions are the most common type in the project area, and they tend to happen in stop-and-go peak traffic. Peak-hour queues "often" block access to driveways and side streets.
Some Corral de Tierra residents disagree with the plan. They have put up signs along the highway, and they told KSBW that the adaptive signals had already shortened the backups. One resident told the station he had been timing the queues on Caltrans' live intersection cameras and said, "It's not what it used to be." He also argued that the agency's own simulation showed only modest relief in the evening peak and none in the morning. A driver interviewed for the same story said construction could disrupt traffic "for sometimes up to a year."
The board heard those concerns. Members discussed the volume of complaints about current conditions, and Board Chair Poduri asked staff to post answers to frequently asked questions on the TAMC website. The board then voted unanimously to authorize a Senate Bill 1 construction-funding application for Phase 1.
The Calendar From Here
The roundabouts are years away. Because of that, the side-street waits from the adaptive signals will likely continue through at least the next few school years.
- November 19, 2026. Nominations for the California Transportation Commission's 2026 Solutions for Congested Corridors Program are due.
- May to June 2027. CTC staff release award recommendations. TAMC's timeline puts them in May, and the CTC guidelines say June.
- June 24, 2027. The CTC adopts the grant awards, according to TAMC's timeline.
- June and July 2027. Caltrans plans to finish right-of-way acquisition in June and design in July.
- October 2027. The project goes out to bid.
- March 2028 to November 2030. Construction is scheduled across the corridor, "subject to construction phasing and funding availability."
Most of the funding plan is still a plan. TAMC's August presentation lists $9.865 million in state transportation improvement funds for design. Right of way would be covered by $6.149 million in state funds and $15.570 million from Measure X. For construction, it lists $6.3 million from Measure X, $6.3 million from the SB 1 Local Partnership Program, and $57.0 million from Solutions for Congested Corridors. The two SB 1 amounts are marked as potential applications. The construction budget depends on whether the state awards that $57 million next June.
The full corridor project goes beyond the three Phase 1 intersections. Caltrans chose the roundabout option for nine intersections from Josselyn Canyon Road to San Benancio Road. Five would be single-lane roundabouts, three would be hybrids with one and two lanes, and one would be a two-lane roundabout. The project also includes five new culverts so wildlife can cross under the highway. Caltrans estimates the roundabout option at $189.2 million for the full corridor. The rejected option, wider signalized intersections with adaptive control and added turn lanes, was estimated at $230.9 million. The option built around signals would have cost more.
The Turn Onto 68, for Now
Until construction begins in 2028, the intersections at the bottom of Corral de Tierra, San Benancio and Laureles Grade will keep running on adaptive signals. Those signals are set up to favor the highway. The published summer data shows longer peak-hour waits on those three side streets than before May. Pasadera saw the opposite. The open questions are how the system handles school-year traffic and whether Caltrans changes the timing in response to complaints. Comments about signal operation go to Caltrans' traffic engineers in San Luis Obispo. The next public decision comes from the CTC in June 2027.
If you own a home on one of these roads and wonder how the roundabout timeline might affect it, whether you plan to rent it, keep it or sell it in the next few years, Carmel Coast follows the Highway 68 corridor closely and is glad to talk it through. Schedule a local consultation.
