Central city car-free workers

And here is the last of the three census-related maps, before I move on to other topics. This one shows the percentage of workers who are car-free (zero motor vehicles owned). Again, the 95814 zip code nails it, at 18.4%, and 95811 is close behind at 14.5%. Yes, I’m one of them.

The near suburbs also show moderate car-free percentages, probably in this case due to low income as much as choice. College (Los Rios and Sac State) students, if they are working, probably also contribute in the near suburbs. Not surprisingly, the distant suburbs have almost no one car-free. Those people are locked into the driving life by the place they have chosen to live.

It is important to remember these percentages are of workers, people who are working somewhere. They do not include people too young to work, people who have retired, or just people not working. If those people are included, the car-free rates would be much, much higher. These people are just as entitled to transportation expenditures as car drivers, but our transportation systems is set up to give them crumbs rather than a fair share.

On the other hand, there large numbers of people in the distant suburbs who have three or more cars per worker. Not per family, but per worker. The 95615 zip code (Courtland) tops the list with 54% having three or more cars, but other zip codes are close behind. Yow!

Again, the Sacramento County map (car-free) is available.



Central city commute times

Here is the second map generated from American Community Survey data, this one showing average commute times by zip code. Nothing surprising here, the central city still compares well with other areas of the county, but there are some interesting patterns in the Sacramento County map (commute time), such as the northeast county in which I’m guessing people are commuting to Roseville rather than downtown, and therefore have reasonable commute times.


If I were looking at commute times for surrounding counties, I suspect the average commute times would be significantly longer, since many people are commuting into employment centers such as downtown, Roseville, and Folsom. I have to admit that my own commute is long, 30 minutes to 90 minutes depending on where I’m working in the eastern suburbs. But I’d much rather be on a bike for 90 minutes than in a car for 20 minutes. I use transit at times, but for most trips it is either the same or longer to my work destination, so I use it mostly on horrible weather days and when I need to get work done on the way there or the way home.

Since this map doesn’t require much explanation, I’ll say more about census data. The American Community Survey has some very complex questions, such as whether you departed for work between 6:00AM and 6:30AM, but it can’t seem to find the bandwidth for some simple but very useful questions such as “Is your commute multi-modal? What percentage?” A person can only answer in one category: car/truck/van, bicycling, walking, transit, or other. If a trip is 51% transit and 49% bicycling, it shows up as an entirely transit trip. If a person drives 15 minutes to a parking garage and then walks 10 minutes to work, it shows up as an entirely driving trip. A number of people have suggested that this single mode constraint over-emphasizes the mode share for driving and therefore underemphasizes walking, bicycling and transit.

I will be looking at the National Household Travel Survey, last completed in 2009, to see how it compares to the American Community Survey. There is also a California Household Travel Survey, which looked at things is a much more detailed manner, but did not provide anywhere near the coverage of a census, sampling only typical parts of the state in detail.

How do central city people get to work?

Many central city residents have claimed recently that they can’t get to work if there isn’t parking both at their residence and at their work. I was curious just how central city folks do get to work, so I delved into census data (more about that below the graphic).

Turns out a lot of central city residents don’t drive to work. In 95814 (where I live) and 95811, about 56% use privately owned vehicles (POV = car/truck/van), but the other 44% walk, bicycle, use transit, or work from home. That is remarkable! When you think about how much attention and money we devote to those who drive, it eye-opening. Other areas near the central city have high active and transit use, but it falls off rapidly in most of the suburbs (but not all). The map below zeroes in on the central city. The Sacramento County Privately Owned Vehicles (POV) Commute is also available.




So, where does this information come from? The American Community Survey, 2014 version, which has estimated data covering a five year period. The report from which I extracted the data is S0801, Commuting Characteristics by Sex. The field mapped above is HC01_EST_VC03, which is “Total; Estimate; MEANS OF TRANSPORTATION TO WORK – Car, truck, or van.” I think the symbology (colors) I used represent what I’m trying communicate – green is good, red is bad.

It took quite some time to find the fields I was looking for, and the search tool does not make it easy (http://factfinder.census.gov/). Then it took some time to figure out how to extract the data fields I wanted and dispose of those I did not. And then it took a LOT of time to figure out how to get ArcGIS ArcMap to match the zip coded commuting data with the county’s zip code map. Turns out that Excel does not properly label the data type of a field, so either the zip code was a number, which didn’t match the text in the zip code layer, or the rest of the data was text, which could not be symbolized properly. I had to use Apple Numbers to create an export format that retained the correct field type. But now that I know how to do this, I’ll have some more maps to share soon.


Car free gains?

I read with interest the Streetsblog DC post “The American Cities With the Most Growth in Car-Free Households” and wondered about Sacramento. I dove into the American Community Survey, using the same 2012 ACS 1-year and 2007 ACS 1-year data that the research had used to look at the number of car-free households in other cities. Over the period when the national average increased from 8.7 percent share of households without a vehicle to 9.2, the six-county Sacramento region increased from 5.7 to 6.8. Not very impressive, but the change or delta was an impressive 18.8%. Yolo County, probably Davis, led this change with a remarkable 76.2% increase!

Below is the chart of change from 2007 to 2012, for the City of Sacramento, El Dorado, Placer, Sacramento, Sutter, Yolo and Yuba counties, and the region, which is an average of those six counties. Following the chart are the numbers I retrieved from ACS. If you would like to look for yourself, go to the ACS Advanced Search, and then under Topics select Housing > Occupancy Characteristics > Vehicles Available.

In the blog post, the largest major city increase was Detroit at 5%, and our neighbor San Francisco was sixth at 1.9%.

I’m not quite sure what to make of these numbers. Is there a flaw in my logic? I had to impute the no vehicle households from the total households and percentages for 2007, because the actual number doesn’t seem to be available in the data tables. Were the numbers so small in 2007 that such large changes don’t really mean much? I don’t know. Your thoughts?

change in no vehicles, 2007 to 2012
change in no vehicles, 2007 to 2012
ACS data
ACS data