And Now for the Not So Annual Why Do We Have Any Credibility Report

Greetings!  It’s been a while since my last post, which is why you’ve seen an entirely new cast of characters writing about all things urban, and providing a new perspective on things.  And nothing wakes me from a deep slumber like a data dump of reams of databases.  That’s right, TTI (Texas Transportation Institute) has released their Annual Mobility Report which just so happens to be the first one since 2012.

I’ve critiqued the Mobility Report before (here, in 2011).  As has CEOs for Cities in their report Driven Apart.  And many,  many, many, others.  It would be the butt of more jokes if so many electeds and randos didn’t actually pay attention to it, because it SEEMS so right.  I was in congestion yesterday. It sucked.  Therefore we need to build more highways.  The economy is good.  Commerce is happening. PEOPLE ARE DRIVING AGAIN.  Therefore, we must build more roads.

All of this is an incredible lesson in rhetoric because if the answer to boom times is build more highways just so happens to be the same answer as when we’re stuck in economic doldrums.  Stimulate the economy, BUILD MORE HIGHWAYS.  As I posted to twitter yesterday, it’s completely illogical to have the same answer for two diametrically opposed ‘problems.’  Further, it’s probably more likely that’s not the answer to either question.



I however don’t care for the report because it is utter nonsense as are their made up metrics and formulas.  I skip the report and conclusions altogether and instead download their spreadsheets.  It is worth it for the raw data they compile.  How many miles were driven this year, what’s the population number they’re using for the metro, how many of that population are driving commuters, what’s the breakdown between highway mileage driven and arterial mileage driven, and most importantly what is the built highway and arterial lane mileage (capacity) in each metro for each year all the way back to 1982.

Except, OOPS, they left that part out this year.  It took them three years to put out less information.  Shall we pat ourselves on the back for digging into their data and showing that their metrics are bunk?  Like here and here.


Here’s the problem:  as every detailed criticism of the TTI Mobility Report points out, their fundamental measure is one of speed.  The metric rewards the places where you drive long distances and do so at the highest of speeds.  It only is a measure for driver experience (without all of the negative externalities of driving).  If you have a two miles drive on city streets where there is stopping and slowing and not getting into deadly accidents.  TERRIBLE PLACES, MESS YOU UP.

It doesn’t take into account whether there are viable, convenient other modes nor economic activity taking place.  In fact, the most ‘congested’ places often happen to be the wealthiest and busiest.  There should be a lesson in there.  Because congestion is a by-product of economic activity.  People coming together to transact goods, services, ideas, laughs, genes, etc.  The best designed cities compress space and time and provide a platform for transaction in the most efficient, elegant, and economical ways possible.  They’re wealthy and economical because there is little energy or financial cost to transact.  Driving and roads is the least efficient way to do that this side of a flying bicycle with wings contraption.

When you take the mobility report seriously, you say “OMG we could save so much money ($160 billion theoretically) if we just spent a few more billion in highway expansion.  A few more billion for each of the 101 metros measured, is of course greater than $160 billion.  Stupid is an endless river.

Listening to the mobility report creates a vicious circle of inertia.  Build a highway, highway gets invariable congested because duh by nature it concentrates mode into space.  Build bigger highway.  City sprawls more.  People drive more.  It gets congested again…or at the very least it *looks* congested according to the report.  Like Detroit, where congestion apparently costs each commuter nearly $1000/annually, more than DFW or Houston.  K.

It’s really a positive measure of the worst cities.  In other words, pretend like TTI is George Costanza and do the exact opposite of what they say and all will be well.


Now let’s look more closely at just the Dallas-Fort Worth metro data.  Some Bullets:

  • Total Miles Driven in DFW peaked in 2013.
  • Total Miles Driven actually dropped in 2014 in DFW by 259,000 miles from 2013.  That’s aggregate for all drivers.  Therefore…
  • Since our population continues to grow, per capita driving is again down.
  • Total driving has also been fairly steady since 2006 hovering between 62 and 64 million miles annually.  And (chorus) since our population has been growing each year…
  • Per capita driving in DFW continues to fall.  Daily miles driven per driver actually peaked in 1994 at 48.01 miles/day.
  • The percentage of the population who is a driving commuter peaked in DFW at 54% in 2006 and 2007.  It has fallen each year to 47% in 2014.
  • TTI’s metrics show that congestion costs were lowest in 1982 at $791/year and peaked in 2006 at $1330.
  • However, when you factor in the total population and not just drivers, the cost of congestion in DFW according to TTI peaked in 1984.  It has fallen steadily each year to its lowest ever point in 2014 where it has bottomed at $766.


So, if we’re saying that distance via how much the total population has to drive is a better measure of a city (less driving is better, more economical, safer, more efficient) rather than meaningless congestion measures, what would those rankings look like using the same data?

Right now, TTI says the most congested cities are:

  1. DC
  2. NYC
  3. LA
  4. San Fran
  5. Seattle

Those places also have a lot of people not driving and getting around other ways.  So if we take a per capita figure rather than per driver figure, those rankings change:

  1. San Jose
  2. Riverside
  3. LA
  4. New Orleans
  5. OKC

That starts to sound more rational because there are more drivers in those cities.  How about what are the best?

  1. Indio/Cathedral City CA – Never heard of it.
  2. Lancaster CA
  3. Winston Salem
  4. Oxnard
  5. Fresno

OK so congestion measures are useless.  How about distance.  Who is driving the most, ie where are the least spatially efficient cities:

  1. Jackson, MS
  2. Little Rock, AR
  3. Riverside, CA
  4. OKC
  5. Beaumont, TX

This includes too many small cities.  How about just metros over 1 million:

  1. Riverside, CA
  2. OKC
  3. Nashville
  4. San Jose
  5. STL
  6. KC
  7. Atlanta
  8. Richmond
  9. Memphis
  10. Cincy
  11. Detroit

Yeah, now the sprawl is revealing itself.  That’s looking more logical.  What metros over 1 million does TTI think are the least congested?

  1. Richmond
  2. Jacksonville
  3. Cleveland
  4. San Diego
  5. Pittsburgh
  6. Tampa – which probably wholeheartedly agrees that they aren’t congested (as in not congested enough) since they’ve just passed sweeping reforms in the way of a Mobility Tax to incentivize infill development.

On the other hand, where does the least driving occur?

  1. NYC
  2. Las Vegas – oddly
  3. Pittsburgh
  4. Portland
  5. Philly
  6. San Fran
  7. Miami

Weird, that’s like a who’s who of most theoretically congested cities minus DC where if you’re a driving commuter from Fairfax County, yeah your commute probably sucks.  And rightfully.  Those externalities and all.

How about just for drivers.  The places where it might be more efficient to get around other ways and drivers have to go very long distances (again just metros over 1 million):

  1. LA
  2. Cincy
  3. Chicago
  4. Memphis
  5. Va Beach
  6. Charlotte

It would be then useful to cross reference that with transit commuting.  Places that have to drive the furthest but have the least transit options would be pretty poorly designed, immobile cities with very little opportunity.  I’m looking at you Memphis.

How about what metros do the most proportion of their driving on highways vs city streets:

  1. Richmond
  2. Austin – because the only two ways north-south are 35 and MoPac
  3. San Fran – interesting.  Presumably because of geography and that most trips in San Fran proper are short and probably not often by car.
  4. Cincy – you’re not showing very well here Cincy.
  5. Minneapolis

That’s about all I’ve got for now.  What is interesting is that we, in DFW, are driving less and less each year.  Sure the population is growing, but aggregate VMT remains steady.  We don’t need more highways.  On the other hand, the proportion of our mileage on highways keeps going up, which is probably why they *seem* more congested than ever.  It’s that we’re not using our city streets, which are 1) often empty or 2) part of an inefficient, fragmented or overscaled grid network.








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