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Our reader Jennifer would like Caltrans to add lane striping past the Santa Rosa Creek bridge on the downtown southbound onramp to Highway 101. Google Street View photo

 

Here’s a question from a reader:

Since the widening of the 101 has been completed, I have waited for someone to finish painting the lanes in the following area: 101 south, Hwy 12 exit just after the on-ramp from Downtown/Railroad Square. Just before the exit splits to take either 12 west or east, there is a section of the offramp that is two lanes wide but is not distinguished as two lanes with paint. It is, however, declared two lanes by the signage above the off ramp that points to one lane being used to enter onto 101 south toward San Francisco and the other to take 12 to Sebastopol or Sonoma. Almost every time I enter this unpainted section of freeway, I have experienced a dangerous situation where drivers are on the right side of the very large lane but are exiting left and vice versa. This section seems like it has been overlooked for painting, and it needs to be remedied before an accident occurs. Jennifer of Santa Roa

The answer comes from Caltrans Transportation Engineer Thomas Kwok, who wrote:

Office of Traffic investigated the traffic concern … regarding the merging/diverging area from southbound US-101 to Highway 12, as follows:

We obtained an as-built pavement delineation plan (dated 4/21/2009) and compared that with our 1993 aerial photo record. Both of them show the exact same pavement delineation on the collector road.

From the plan, the merging/diverging area (which effectively is a wide lane) has a total length of 160m (or about 520 feet). If a lane line is added to delineate the collector road into two lanes as requested by … (the) reader, the area will effectively become a weaving area. The slightly curved lane configuration would reduce the effective weaving length to less than 450 feet. According to the design standards, Manual of Uniform Traffic Control Devices, the minimum weaving length should be 600 feet.

Under the current situation, a merging/diverging maneuver is considered operationally more forgiving to a motorist than a weaving movement. This is reflected in a negligible accident experience on the collector road.

Based on our record, there had been one reported collision in the latest three-year period from 4/1/2008 to 3/31/2011. It was a non-injury, rear-end collision.

Based on the above assessment, Office of Traffic does not recommend any changes to the pavement delineation that would alter the existing traffic movements.

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If you have a question for the Road Warrior, please send it to jim.fremgen@pressdemocrat.com

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Comments

6 Comments

  1. Me

    And while they are at it, how about a “lane ends” sign at the Mendo onramp lane heading south 101. Not only are people merging onto 101 from that lane, but when traffic is slow or stopped, people are using it as a passing lane on the right and then getting stuck or trying to crowd those in the right lane over.

    October 13th, 2012 10:11 am

  2. doug

    This question is not very relevant. The relevant question is why does the north bound ramp from hwy 12 to 101 south end before Corby ave. ? Why is the Todd rd. on ramp going south bound on 101 still so short? There is not enough room to get up to speed. The whole project was politicized and corners were cut so that the highway could be widen with out the input of people who know so little about traffic. I say this because people who don’t have their heads in the sand realize that it takes most cars more than 100 yards to get up to 70 miles an hour, the speed that cars traveling. Vote out Sonoma County legislators! Time to move your money lined pockets out of our way.

    October 13th, 2012 11:06 am

  3. Trevor

    “Based on our record, there had been one reported collision in the latest three-year period from 4/1/2008 to 3/31/2011. It was a non-injury, rear-end collision.

    Based on the above assessment, Office of Traffic does not recommend any changes to the pavement delineation that would alter the existing traffic movements.”

    So if I am reading this right, not enough accidents have happened to pay for this? I understand if no accidents are happening then they may not be an immediate need, but wouldn’t a little paint go a long way to possibly help prevent future accidents?

    October 13th, 2012 12:18 pm

  4. RWB Reader

    If Caltrans were to stripe lanes the whole way through the ramp, then they would be intentionally going against design standards. I’d say that’s a pretty good argument for not doing it.

    And Doug, assuming for a moment that your comment makes sense (because Hwy 12 does not go north, and the onramp ends before Corby because it can’t just go on forever), wouldn’t it be a good thing that Caltrans widened the freeway without consulting with people who don’t know about traffic? And what do “Sonoma County legislators” have anything to do with freeway onramps?

    October 14th, 2012 12:57 am

  5. devildog

    Hey, who needs lane striping? It keeps you guessing! Keep life interesting! Oorah

    October 15th, 2012 10:46 am

  6. Patrick

    Trevor, so your attitude is fix it until it is broken?
    I drive this section of highway every morning and have never seen any unsafe action here. Now the northbound exit to downtown (with the Hwy 12 merging into 101 at the same spot) is a real mess. The drivers going from 12 to 101 North hate letting the people exit 101 to downtown merge through their line. I assume for fear of extending their drive time by 5 seconds.

    October 15th, 2012 1:43 pm

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