Sunday, July 29, 2018

Comparing Costs of Transit Modes

Podcar technology holds promise to deliver far greater economy and far greater capacity than conventional public transit.

Podcars will come to terms with public transit – unaffordable in emerging economies and heavily subsidized in market economies. Examples from the USA demonstrate the technological inadequacy of current public transit modes.

ModeCost/mileCost/km
Heavy Rail $262 million $162 million
High Capacity Rail $256 million $159 million
Light Rail $171 million $106 million
Streetcar$38 million$24 million
Commuter Rail$36 million$22 million
Bus Rapid Transit$9 million$6 million
Average All Modes$89 million$55 million
Public Transportation Investment History • Background Data • Table 23
APTA 2015

Capacity
Superficially it would appear that public transit has high capacity.
Light Rail can hold 255 people in each vehicle, which in turn can be linked into a train of two or more cars. Light Rail is smaller and slower than High Capacity Rail, but travels faster and carries more passengers than streetcars or buses. High Capacity Rail is larger and longer, holding up to 1500 passengers (in ‘crush’ conditions).

High Capacity Rail gets power from an electrified rail below the train and requires large stations, more infrastructure and safety separation. Light Rail can run above ground at street level, like streetcars, however it operates in separated lanes, meaning it is not affected by car and truck traffic. Stops are planned to be about 500 metres apart, but closer than High Capacity Rail stops. For more details, please refer to Passenger rail terminology in Wikipedia.
These numbers seem compelling but such High Capacity Trains require long headways, with extensive empty sections of track between trains, equivalent to trying to make a bucket brigade more effective by using larger buckets. In reality a fire hose carries more water by streaming it.

High capacity rail systems require stations too large to fit above ground in dense urban areas or to be affordable in suburban settings, and trains usually stop at all stations en route.

Relative Capacity per Hour (not all seats are filled)
ModeSeats per VehicleHeadwaySeats per Hour
Bus 0-50, 50 used5 mins600
Light Rail0-200, 200 used10 mins1,200
Automobiles1-6, 4 used(3 legal) 1-6 secs4,800
Podcars1-8, 4 used3 secs4,800
Podcars1-8, 4 used1 secs14,400
Podcars1-8, 4 used0.5 secs28,800
Podcars1-8, 4 used0.25 secs57,600
* 0.25 second headway gives each vehicle 3.91 meters of space
Adapted from JPods 2018

The capacity of the vehicle is not the throughput of the network.

Operating Costs

When these high capital costs are amortized over time to be repaid at the farebox, deficiencies are deflected into subsidies. Public transit systems are heavily subsidized throughout the world, with some notable exceptions in east Asia and London. (Curiously, the farebox recovery rate in Silicon Valley is one of the poorest, on the order of 10%, where it costs more to accommodate a public transit commuter than it costs to own and operate a car.)

(Source: Wikipedia)
Aspiring podcar vendors estimate that their costs will be much lower that other forms of public transit, due to a number of factors. For example, this chart from JPods demonstrates, surprisingly, that before even considering the advantages of podcars, due to high labor costs and low ridership, buses are even more expensive than private automobiles. 

Safety

Another important cost metric is safety.


2016 motor vehicle crash highlights
Deaths 40,327
Medically consulted injuries 4.6 million
Cost 416.2 billion
Motor vehicle mileage 3.174 billion
Registered vehicles in the United States 269 million
Licensed drivers in the United States 222 million
Death rate per 100 million vehicle miles 1.3
Death rate per 10,000 registered vehicles 1.5
Death rate per 100,000 population 12.5

Injury Facts, National Safety Council

All of this occurs under sovereign immunity and self-regulation by Federal and State Departments of Transportation. By contrast, 0.2 per million injuries occur on amusement park rides, under ASTM-F24 standards.

By removing sovereign immunity, government officials would be personally accountable, operating as commercial mobility networks. Radically safer transportation networks would replace the unsafe, internally regulated government monopolies.
 
More

Future posts will delve into these factors in greater detail.

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