Thursday, December 19, 2013

Parking and Dying in the CBD

I took a moment today to crack open an old favorite, Donald Shoup's High Cost of Free Parking.  This book is the bible for parking policy these days and a great reference manual to have around the office library.  What caught my eye today was a table comparing parking quantities in various Central Business Districts from around the world.  However, Dallas was not included.  So I decided to dig up some data to find where Dallas would sit in the table.

The Table charts and ranks these categories:  Land Area of the CBD (in hectares), Number of Parking Spaces, the Parking Area, and Number of Jobs in the CBD.  From there Shoup includes ratios between these various data points such as parking coverage of the entirety of the CBD, Parking spaces per land area, and Parking Spaces per Job.

Now it's worth noting that this data is fairly old.  It's taken from a 1999 study by Kenworthy and Laube.  However, the Dallas data is fairly new, primarily coming from the Parking portion of the Downtown Dallas 360 Plan.  The table of cities however is basically a shaming device for Shoup's home city of Los Angeles, which at the time was the runaway winner for overindulged parking provision.

I measured the CBD (the area within the highway loop) to be about 368 hectares, right in between Houston (392) and Detroit (362).  The 360 study lists the parking count of Dallas CBD at 68,000 spaces, again right in between Detroit (65,639) and Houston (72,797).  The 360 report suggests a coverage of 27%, however looking at their map that seems low.  It's also well below our nearest peers Houston (57%) and Detroit (56%).  Even DC is listed at 54%.  Either way, that figure is far less relevant than parking quantity per area and parking spaces per job.

I haven't been able to track down an accurate number of jobs as of yet, but a number I've often heard is ~100,000 in the CBD, which again puts it in the territory of Houston (303) and Detroit (257)  in terms of Jobs per Hectare (271).  Hong Kong is at 1,713 if you were wondering what the upper limit was.  Canberra and Phoenix offer the low end at 68 and 90, respectively.

In terms of Parking Spaces per Job, this puts Dallas at .68, again in between Houston (.61) and Detroit (.71).  These numbers are quite a bit higher than Tokyo (.04) or New York (.06).  While this hasn't yet been aggregated, I would bet there is a pretty significant correlation between Parking Availability (as measured by spaces per job) to Transit Ridership (or at least alternative transportation).

I'll have to compile that table next.