sloRecent U.S. Highway 101 upgrades in SLO County bring corridor needs into focus

February 26, 2011

Caltrans Central Coast Director Rich Krumholz


Caltrans has received some questions lately regarding a recently completed project in the south county. Meanwhile, motorists throughout the county are experiencing more frequent and often unpredictable delays along the US 101 corridor. While addressing this issue, it is important for me to also highlight an underlying and growing need facing the central coast.

Specifically, I’ve been asked why the climbing lane on southbound US 101 from Avila Beach Drive does not extend all the way to the Spyglass Drive exit in Shell Beach. The purpose of this third lane is to allow slower moving traffic going uphill to move right so that other traffic can pass while maintaining speed. This reduces conflicts between slower and faster moving vehicles. As a result of this climbing lane project, we have seen fewer collisions involving vehicles traveling at different speeds since its completion in the spring of 2009.

The new lane ends just beyond the crest of the roadway and before the Spyglass Drive exit. Ending the lane before the exit follows a key principle of roadway design:  provide enough space for drivers to make one decision at a time. On the flatter area over the crest, slower moving traffic has time to get back up to prevailing speeds and safely merge into the flow. This merge happens before drivers make another decision and eliminates any competition between vehicles merging and exiting.

This decision sequence differs from what drivers experience with auxiliary lanes, also known as merge or weaving lanes. Last year, we completed construction on a series of these lanes on US 101 between several interchanges in Pismo Beach and Arroyo Grande. These lanes work by alleviating conflicts between vehicles entering and exiting the freeway, which allow drivers to equalize speeds and then exchange places between on/off-ramps.

Still, drivers are becoming increasingly frustrated as US 101 reaches its service capacity. We have all experienced travel delays during morning and evening peak commute times throughout the county.

Unfortunately, more congestion not only slows us down, it increases the probability for traffic incidents. With increasing frequency, these incidents cause significant delays affecting the daily commute. While bottleneck areas at certain times of the day are predictable, incidents cause delays that are very unpredictable. All of this threatens the reliability of our main transportation corridor, which undeniably serves as the backbone for this county and the entire central coast region from Santa Barbara through Monterey County.

It is clear that we must continue investing in the right projects throughout San Luis Obispo County and elsewhere on the central coast to keep the Highway 101 corridor vital and healthy.

So, with an opportunity to address the intermittent bottleneck near Avila Beach Drive, we constructed a climbing lane. In order to reduce conflicts created with closely spaced on/off-ramps, we built auxiliary lanes. These types of projects address problems at spot locations but cannot alleviate the underlying demand that continues to grow in this corridor.

This fall, Caltrans will begin construction on a long-awaited project to widen the bridges over the Santa Maria River at the county line. This $50 million project will improve traffic flow for all vehicles with a third lane in each direction and it will provide safe connectivity for bicycles and pedestrians with a separated two-way path on the western side of 101.

We also recently improved the interchange and freeway merge at Highways 41/101 in Atascadero and are working with the City of Paso Robles to make spot improvements along US 101 between Highways 46 West and East.

However, answering the demand does not always mean adding freeway lanes. A variety of solutions may include frontage roads, interchange modifications and elimination of intersection crossing movements as well as efforts that make transit and passenger rail more viable. We need meaningful, comprehensive upgrades that meet the future needs of the central coast community.

We’re working with our partners, the San Luis Obispo Council of Governments (SLOCOG), to focus on US 101 as a top regional transportation priority. Furthermore, this partnership is expanding with our neighboring central coast counties of Santa Barbara, Monterey and San Benito on a newly- formed coalition to address the critical needs along the corridor, our central coast lifeline.

If we value our coastal quality of life and hope to preserve our economic vitality, we need to face this issue head on by identifying and investing in the best projects for the greatest benefits. A good place to focus our energy is in regional transportation planning and SLOCOG is in an important position to shape our future. They need our input and support them in this role.

Richard Krumholz is Caltrans’ District 5 Director.



  1. mkaney says:

    It seems that Rich is too enamored with his own brilliance on freeway academics to consider that the problem may not be climbing lanes but NUMBER of lanes, and by that I do not mean more freeway lanes, I mean providing alternate routes and a movement AWAY from pod communities and collector roads. Limit the number of freeway exits in communities, build out more connector roads between communities, and require businesses and developers to provide access to their properties (e.g. don’t SUBSIDIZE people by building roads FOR them)…

    (1) 1 Total Votes - 1 up - 0 down
  2. ApathyWillKillYou says:

    Hey Rich,

    Would you please post on this site where to go to get reimbursed by CalTrans for all the damage done to North county vehicles on 101 between 58 and 41 due to excessive BUMPS caused by recent construction.

    Be a MAN and admit these BUMPS caused untold damage. You know when you drive down the freeway you don’t expect VIOLENT bone jarring obstacles in a 65+ MPH corridor caused purposely by shoddy unfinfished construction! But then again I would bet that you NEVER experienced those BUMPS personally or you are too embarrased to admit it.

    Sorry to rant Rich, but I’m looking at over $2000.00 in repairs… a mere pittance for an upper management CalTrans employee.. but a fortune to a person that NEEDS their vehicle to SURVIVE!

    (-2) 10 Total Votes - 4 up - 6 down
  3. Cindy says:

    Thanks for the update, at least I understand what the plan was or wasn’t. Being aware of the perceived hazards and their intended remedies is always useful when on the road and driving through those frustrating areas.

    (2) 2 Total Votes - 2 up - 0 down
  4. Jim Zim says:

    I think Caltrans just plain blew it with their decision to end the Avila Beach climbing lane short of the Spyglass exit. I drive that stretch almost every day, and it simply creates problems that could so easily have been prevented if they had taken that climbing lane a little further. Please fix it!

    (7) 7 Total Votes - 7 up - 0 down
  5. ApathyWillKillYou says:


    101 North from HWY 58 to HW 41 is still NOT finished and it is DANGEROUS!

    The 101 and 41 interchange costs MILLIONS and all it achieved was that it is different… not better just different and not to mention all the business that went under during the extremely lengthy construction period that is STILL going on!

    Squiggly painted lines and no lines on the highway at all make it extremely dangerous at night and in the rain!

    And those BUMPS have caused all of my vehicles to have the front end aligned as well as having shocks and ball joints replaced!

    And the scheduling of road work at times is awful! I have seen cars backed up for miles and miles waisting peoples time and gas while polluting massive amounts by all those vehicles idling!

    CalTrans seems to have billions to spend on roads while people are loosing their jobs and homes yet they can’t even build or repair a road correctly or in a reasonable amount of time.

    (6) 8 Total Votes - 7 up - 1 down
  6. danika says:

    Psssst…Rich? Have you actually driven on the 101 in Atascadero approaching the 41/101 interchange in either direction say, in the last 4 months? How many times have YOU had to have your car aligned, hmmm? You call it improved. I call it extortion for job security, Rich. Get rid of those “bumps” before someone gets hurt…

    (4) 6 Total Votes - 5 up - 1 down
  7. bobfromsanluis says:

    Rich: In my opinion, you did not give a fully logical answer as to why Cal Trans did not extend the climbing lane from the southbound Avila on ramp to the Spyglass exit. Your attempted explanation of limiting the drivers to only having to make one decision belies the actual usage of such a lane. You of all people would know that having the shorter, closer spaced striping on the roadway helps to differentiate a through lane from a dedicated exit lane, and there are usually signs labeling exit lanes as such. Honestly I don’t think Cal Trans gave the idea of extending the climbing lane clear through to the Spyglass exit enough thought. Perhaps a survey could be conducted, whether it is a scientific based model or a simple poll that you could have people comment on, I think you find that an overwhelming number of drivers would think that extending that lane all the way to the exit makes a lot of sense. I do appreciate the hard work that Cal Trans performs and the thought process usually exhibited by how well traffic usually flows on the highways and freeways.

    (10) 12 Total Votes - 11 up - 1 down

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