Commentary: Studies Link Housing with Traffic, but in the Opposite Way that You Think

Richards Tunnel

It never fails in Davis, you have a housing project and the opposition will make the argument that it will increase traffic.  Even in the case of Nishi, where the new version intentionally avoided the congested Richards Boulevard, opponents strained to attempt to connect Nishi to traffic problems, arguing that the presence of 700 parking spaces would mean additional traffic on Old Davis Road as well as into the Davis Downtown.

The problem with the argument is evident with a scrutiny of what is actually likely to happen.  First, most of the residents at Nishi will be students and most of them will bike, walk or take the bus to campus rather than drive.  Travel studies over time show time and again that students who live within a mile of campus don’t drive to campus, they use other means to get there.

Because Nishi isn’t adding to enrollment, but rather finding those already enrolled a new place to live, closer to campus, Nishi has the potential to reduce traffic – not increase it.

Off-peak hours, yes, some of those 2200 residents, 700 of them at most with cars, may drive off site, but the traffic figures to be a trickle, not a rush.

One of the biggest reasons that Davis has a traffic problem, particularly on Richards, is that there is a large number of people each day driving outside of Davis while there is another large number of people driving into Davis, both mostly for work or school.  A better mix of housing-jobs would improve traffic flow.

A study published last weekend in the Mercury News found something similar – for San Mateo County.  They found that “jobs are booming, but housing growth has stalled and commuters are spending more and more time stuck in traffic.”

A new report by housing and transit advocates finds “the rejection of new housing developments in the county has led to more, not less, congestion as workers move farther away to find affordable housing. One new home was built in San Mateo County for every 19 jobs created between 2010 and 2015.”

Just like in Davis, many people in San Mateo have fought against new development in part because they are “really concerned about traffic,” said Evelyn Stivers, executive director of the Housing Leadership Council of San Mateo. But, she added, “not building housing really causes traffic problems.”

The issues in San Mateo County are a bit different.  It is not just lack of housing, it is lack of affordable housing.  The report in the Mercury News notes that San Mateo County is the home to a growing number of highly paid tech jobs.  But those workers are supported by a number of lower-paid service workers.

While the median income in the county is around $118,000, “[t]he county has more than 100,000 service and retail workers making less than $25,000 annually.”  However, even the median income is “less than one-third of the annual salary needed to purchase a home with a 10 percent down payment.”

The problem is clearly far worse in San Mateo than Davis, but that speaks to the need to ask.

A key variable in reducing traffic is putting more people in closer vicinity to work and school.

We can look at the UC Davis Travel Survey and they found in their weighted sample of 767 students that those living within a mile of campus do not drive to campus – only 2.2 percent either drive alone or carpool.  On the other hand, 76 percent bike, 17 percent walk and 4 percent use the bus.

So, during peak hours, the flow of motor traffic out of Nishi figures to be extremely low.

During the campaign, we looked at alternative models of where students would most likely live if Nishi had not been approved.

Where do the 2200 students live?  One option is that they will commute from out of town.  If that’s the case, they will drive in via a car.  The UC Davis Travel Survey tells us this – of those living five miles or more from campus (i.e. anyone living out of town), over 90 percent drive either by themselves (more than 75 percent) or in a carpool.  So not building Nishi would bring, as the university grows, a ton more of traffic to Richards and also Olive Drive coming off the freeway.

Second option, they can jam into existing housing.  While most people who live in the city do not drive to campus, many will nevertheless drive either to the downtown or elsewhere at other times.  In addition, while most don’t drive to campus, the proportion who do increases as they get further from school.  So, within a mile 2.2 percent use a car, but that increases to 15 percent within three miles and 43 percent within the three- to five-mile range.

Third, they can live on campus.   This seems to be the preferred option for those opposed to Nishi.  We have heard it time and again.  But guess what, the travel habits are going to be similar.  Let’s say they live in West Village rather than Nishi.  They will still bike, walk or take the bus to campus just as they did at Nishi.  And they will still potentially at least drive to town during other times.

Nishi, in fact, puts students in easier walking or biking distance of downtown than West Village, which requires a one- to two-mile hike or bike trip.

The key factor here is, if you want to argue that students at Nishi will still drive at times into town, the same will hold no matter where they live because the act of building Nishi is not going to increase enrollment.  Those students will still be here and still have to live somewhere.

My argument is simple – fewer students will drive to campus each day if you put 2200 of them at Nishi than if you don’t build this additional student housing.

This seems to be common sense, and yet for some reason we continue to believe that building more housing will lead to traffic impacts, without exploring the corresponding decrease in car use as the result of close proximity of housing to the university.

—David M. Greenwald reporting


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About The Author

David Greenwald is the founder, editor, and executive director of the Davis Vanguard. He founded the Vanguard in 2006. David Greenwald moved to Davis in 1996 to attend Graduate School at UC Davis in Political Science. He lives in South Davis with his wife Cecilia Escamilla Greenwald and three children.

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16 Comments

      1. Howard P

        Something all traffic engineering folk know… not residential per se, not commericial/’work’   per se… has a lot to do with the proximity of “origins” and “destinations”, and the mix of mode choices available.  Those factors drive “traffic”… and, magnitude and duration during the day…

        This article might move the knowledge level of the general public a tad forward… which is a good thing…

        1. David Grundler

          Howard, I don’t dispute that. I, in general, don’t click on article links that are over sensationalized. “Check out what just happened, you aren’t going to believe it.”

        2. Howard P

          John… if you’re comparing me to either “Sanders’ role”, or my resemblance to her (on many levels… main one being gender), I’ll have a “bone to pick with you”… am assuming you are doing the “bon mot” thingy… cool, if the latter…

          Actually she is between a “rock and a hard place”, IMO… must be a strong woman, or really needful of the income, to do that… her “Boss” (apologies to Springsteen) cannot sometimes keep his “twittered” opinions/views consistent within 2-3 ‘news cycles’…

  1. Dave Hart

    I do believe most voters understood this link to proximity and traffic and that is why Measure J passed so heavily.  Similarly, I believe most voters use our parks (by definition that means they view the condition of parks and greenbelts on foot and close up) and that is why they voted to continue the parks tax.  And, finally, I believe most voters have observed the conditions of city streets and voted to support the roads tax.  Except, of course, we allow the minority of voters who only drive cars and have little appreciation for the condition of city streets as viewed through the windshield to veto the wisdom of the majority.  It’s all about perception, common sense and personal experience.  None of these issues are complicated.

    Giving the minority the power to veto the majority is really stupid politics.  Not off topic here, because it shows how wrong the minority is on an issue like Measure J.

    1. Mark West

      “None of these issues are complicated.”

      Neither is economic development, which would reduce or eliminate the need for the incessant tax increases, yet we continue to ignore the obvious in order to protect the minority who oppose business expansion.

      1. Dave Hart

        Mark, I agree with you to the extent that the electorate or citizens in general do not see the economic development clearly in terms of their own, personal lives.  I would argue that economic development is fuzzy in many people’s eyes.  They understand their own job (which may or may not be private sector) and the situation of their own employer but often fail to see all the feedback loops in the general economy.  And, maybe they are afraid that the only model looks too much like the soul-sucking sprawl that is apparent in many other communities.  I just don’t think that Davis voters feel like they have had a clear choice.  I suppose that time is coming and I hope it won’t be a decision driven by desperation alone.

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