"Traffic Plans" and Fundamental Laws of Congestion

Legislators, planners, experts, and advocates have identified plenty of cures for ridding highways and roads of the slow traffic that robs commuters of their time.  Here we offer some random observations.

Cure All:  Generous Investments in Public Transit

 Best:  Redfin Survey 02/21/18                                   Worst: Inrix Global Scoreboard

Best:  Redfin Survey 02/21/18                                  Worst: Inrix Global Scoreboard

The chart on the left shows 2017 ranking of the top 10 U.S. cities with populations of more than 300,000 for public transit.  The chart on the right shows 2017 ranking world-wide of U.S. cities with the worst traffic congestion.  The highlighted cities could claim that were it not for their considerable investment in public transit, traffic would be much worse than it is.  Others could claim adding transit does little to affect automobile traffic.

Ridership Trends

Of the 10 cities ranked as best for public transit in the chart above, only Seattle gained in transit ridership from 2016.  It appears that being among the “best” does not guarantee being effective.

How Much Would You Pay to Ride the Bus?

Somebody Has to Pay

If you take public transit in Los Angeles, you probably need to spend around 8.69% of your income to purchase your monthly transportation pass.  That is a considerable percentage.  However, Los Angeles Mayor Eric Garcetti seems to be looking for ways to raise that percentage even further.  On a 2016 interview with Newsweek, Garcetti laid out his vision of what Los Angeles transit would look like by the time he leaves office.

The centerpiece of Garcetti’s vision is Mobility Plan 2035, released last summer, its name a subtle allusion to the immobility that now grips every corner of this huge and restless city. The new mobility would come at the expense of the car. There is also Vision Zero, an initiative to eliminate traffic fatalities modeled on Stockholm’s program of the same name. Los Angeles also has Great Streets and Complete Streets and People St, all different plans to fight the same four-wheeled enemy. There will be a subway to the sea, finally. There are now bus shelters with smartphone chargers.

Sounds like cost of transit as a proportion of personal income is about to climb higher than the current 8.69%.  Or maybe Garcetti plans to have automobile commuters across the Los Angeles River bridges pitch in?

The Fundamental Law of Highway Congestion

Way back in 1962, transportation researcher Anthony Downs declared that the fundamental law of highway congestion would cause any empty or near empty highway lane to soon fill up with automobiles.  You build an extra lane, and extra cars will soon populate it to capacity. 

In 2011, a team of three researchers declared that Anthony Downs’ law could extend to roads around and within cities, and the fundamental law of road congestion was discovered.  If a newly-built lane that starts out empty is soon filled up with cars, then an old lane made nearly empty by government edict will also soon fill up as well.

Say, legislators and bureaucrats succeed in getting everybody walking, biking, carpooling, and taking public transit; then the presence of single-occupancy automobiles would decrease, leaving room for walkers, bikers, carpoolers, buses and rail transit to zoon by.  Given the fundamental rule of road congestion, it would not be long before single-occupancy cars also started zooming by, taking advantage of the now empty spaces.

You Can Lead of Horse to Water, But...

Transit advocates say that the pesky laws of traffic congestion can be eliminated by changing people's behavior.  Maybe, but past experience shows us differently.  Here is a recent Los Angeles experience, reported in the Los Angeles Times, that should give some pause to Mayor Garcetti and others on a mission to eliminate cars:

Despite a growing population and a booming economy, the number of trips taken on Los Angeles County's bus and rail network last year fell to the lowest level in more than a decade….

Experts and officials have no firm answers, but have attributed the decline to a combination of factors, including changes to immigration policy, competition from Uber and Lyft and more people buying cars — as well as perceived problems with existing transit service and security.

It appears that although a segment of residents in any city will always be committed to walking, biking, and riding public transit, what we see in majority behavior is that as soon as people can, people will ride cars. 

So Are We Stuck With Gridlock?

If the type of central planning now in vogue - primarily shabby transit oriented development, accompanied by the concentration of jobs in a few locations - persists, it will be difficult to improve the traffic situation.