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Estimating Costs of LoopWorks PRT Technology

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Estimating Capital Costs of LoopWorks PRT Technology (also consider Operations & Maintenance Costs)

The following graph shows industry-accepted capital cost estimates for PRT systems under varying conditions and number of cabs per kilometer (multiply by 1.5 for cabs per mile).

A chart similar to the one above can be found on PDF page 54 of Mineta Transportation Institute's 2014 report:
Also in that report is this summary of costs:
"For medium-capacity applications, system and major civil costs of $10-$20 million per elevated one-way mile appear to be reasonable (Figure 33).
This includes guideways, stations, vehicles, maintenance/storage facilities, control systems, etc., but it excludes external costs (utility relocations, right-of-way acquisition, special artwork, etc.).
Kerr, James, and Craig in 2005 found that ATN infrastructure per mile costs about one-third of that for APM, and ATN stations cost about one-half of that for APM."

However, in the case of cost per cab, the graph above may overestimate the cost. Following is an explanation of why.

# of PRT cabs to populate a mile of guideway -- and the cost.

At 30 mph with headways (spacing between podcars) of 2 seconds (as recommended for human-controlled cars),
each PRT cab covers 88 feet every two seconds.
30 mph = 5280 ft * 30 miles/hour ÷ 3600 sec/hour (60 seconds * 60 minutes) = 44 ft/sec. = 88 feet every 2 seconds
So, it only takes 60 cabs to populate a mile of guideway.
5280 ft/mile ÷ 88 ft/cab = 60 cabs/mile

If cabs cost $50,000 each, it only costs $3M to populate a mile with cabs. (60 cabs/mile * $50,000 = $3M)
Although cabs are not mass produced, they don't have expensive batteries, complex steering and suspension, or heavy gas motors
(fuel tank/pump/injectors, radiator/water pump/hoses, transmission and drive train, crumple zones, ignition system, muffler, catalytic converter).

PRT Industry Rule of Thumb: 50% of PRT cost goes for guideway, 50% for cabs

So, either the rule of thumb is wrong,
or cabs cost more than $100,000 each,
or guideway costs less than $7.5M/mile.

Regardless which is true, it appears that $15M/mile is a conservative estimate.

According to this breakdown of costs (that can be found on page 13 of How to Reduce Congestion and Save Energy), the rule should be more like
42% of PRT cost goes for guideway, 25% for cabs

According to "Personal Rapid Transit for Microsoft and Bellevue" by Jerry Schneider and Steve Raney:
It is possible to produce PRT at a low delivered cost of $10M per mile, as well as a high $40M per mile. A model whereby engineers have financial incentives to keep costs down will be more advantageous than that of a traditional "cost plus" manufacturer that passes on cost overruns to taxpayers.
Such a wide range of estimates - $10M/mile to $40M/mile - stems from the many variables available to PRT designers as shown in this chart.

By choosing an inexpensive guideway design and small cabs as proposed by LoopWorks, overall costs are dramatically reduced. Costs could be further reduced if Bosch Captive Column technology is employed in the guideway design.

Another indication that $15M/mile is a conservative estimate (especially for Taxi 2000 technology) comes from a 2004 report by TRANSEK Consultants for the project entitled European Demonstration of Innovative City Transport (EDICT). Included in the report is the following chart comparing costs between Bus, PRT, LRT and AGS (Automated Guideway Systems or "APM" in the US). Each estimate includes the total investment costs for guideway, vehicles and stations for the different systems. Bars in blue are Stockholm systems, in green are PRT systems, and in brown are other systems.

The three Stockholm LRT systems costs around 15-20 M Euro per track-kilometer (24-32M€/mile). A summary of 22 Automated Guided Systems in the US have an average cost of 17M Euro per track-km (27M€/mile). All three PRT systems show a lower investment cost than the studied LRT systems with Austrans at 9 M€, ULTra at 5.6 M€ and Taxi 2000 at 3.4 M€ per kilometer. An average of the three PRT systems yields an investment cost of 6M€ per track-kilometre (9.6M€/mile).

If we extract the Taxi 2000 cost of 3.4 M€ per kilometer (5.5M€/mile),
use the 2004 date-of-publication conversion rate of 1.2 dollars per Euro ($6.6M/mile),
and factor in a 1.26 inflation rate since 2004,
current costs are estimated to be only $8.3M/mile
-- far less than the $15M/mile estimate for the "average" PRT system cited on this website.

Another cost estimate was developed by members of the Sky Loop Committee in Cincinnati. Last revised in 2001, it included a table of costs as part of the financial analysis section. That table is provides a detailed estimate of the cost of a PRT system with Taxi 2000 attributes. Their 2001 estimate of $5.5M total capital costs per mile rises to $7.4M/mile in 2015 dollars after adjusting for inflation.

The following graph and text show cost estimates for transit infrastructure depend upon vehicle and support structure weight.

According to this ATRA document, PRT infrastructure can be provided for one-third the cost per mile of equivalent APM infrastructure, and PRT stations for half the cost or less of APM stations.
This news article says the SkyTran flavor of PRT infrastructure costs $13M per mile ($8M per kilometer).
This news article says the 2getthere flavor of PRT infrastructure costs $24M for 2.5 miles, or $10M/mile. The Modutram flavor of PRT infrastructure costs $16M for 2.5 miles, or $6.4M/mile.
The Morgantown GRT upgrade includes some real-world cost estimates for various components.
The ecoPRT website claims their system will be much less expensive than PRT systems such as Heathrow Airport's UltraPRT.
"EcoPRT has a target cost for guideway at $1 million per mile. ... Vehicles will use off-the-shelf components and a lightweight design to keep up-front vehicle cost as well as maintenance costs low. The target vehicle price is $10,000 or less."

In 2016, two companies bid on the 2.5 miles of one-way guideway needed at the Greenville-Spartanburg Airport. At the estimated construction cost of under (and well-under) $25M, companies are now bidding PRT systems at $10M/mile rather than the $15M/mile used for Milpitas estimates.

In 2017, responding to requests of the of the Santa Cruz County Regional Transportation Commission for public input about its Draft UCS study, Santa Cruz PRT, Inc. submitted a proposal that uses a $15M/mile estimate for guideway cost (see page 5, BUDGET).

When considering cost, one should also consider benefits. One factor on the benefit side of the equation is the ridership.

In the 2005 Paper presented at the 19th International EMME/2 Users' Conference in Seattle (19-21 October 2005), Transek Consultants predicted an increase in ridership. Specifically, 3 times more Transit Trips with PRT compared to bus mode:

"Of today's 42 000 daily visitors, the bus mode carries some 2 350 or 5,5%. In 2015 – with the Kungens Kurva area fully developed – almost 1 out of 5 visitors is expected to go by public transport, of which 17.3 % or 11 000 by the PRT mode. This modal split is almost four times higher than today. PRT will provide an environmental-friendly and attractive complement to the private car and it also draws more passengers to metro and bus." Here is the modal split without and with PRT:

Here's another chart Transek produced to show modal split:

Transek also predicted a reduction in trip time.

The proposed PRT network for the King's Curve Area in Sweden
Door-to-door trips faster with PRT
The total travel time between Skärholmen and Kungens Kurva will be reduced from 14 to 8 minutes incl. walk time with PRT, i.e. a 41 % reduction.
The total travel time from Stockholm city to Kungens Kurva can be reduced by 26 % from 65 to 46 minutes (incl. walk and wait time).
In off-peak, the travel time gain will be 20 minutes between Stockholm City and Kungens Kurva with PRT.

Transek also performed a Cost/Benefit Analysis comparing PRT to the other transit options available:

Cost Estimations of PRT, LRT, Disney Monorail by Visual Impact

The image below shows the relative sizes of PRT guideway (purple), elevated LRT railbed (gray), and a man. The guideway supports the monorail tram (not shown) located on the grounds of Cal Expo that was installed in 1968 and still operates during the annual State Fair. Its size and weight is comparable to the Taxi 2000 guideway. The elevated LRT railbed with man has been PhotoShopped into the original image.

Here are images of the monorail at the 1967 World's Fair in Montreal. In addition to showing relative size, these images also show the tight turning radii and flexible routing of such small-sized systems. Due to size of the vehicles (12 passengers rather than 4), the monorail must be bigger than LoopWorks' guideway, and its supports both bigger and more frequent. (These screenshots come from an 8-minute film about the Fair.)

The image below shows the relative sizes of Disney Monorail guideway, elevated LRT railbed, and PRT guideway (minimalist type: TriTrack). The small print shows that the Disney Monorail uses 5,800 cu. yards of concrete and 1200 tons of steel per mile, while the elevated LRT railbed uses 28,000 cu. yards of concrete and 2900 tons of steel per mile. The elevated LRT railbed built through Milpitas cost about $120M/mile. As you can see, TriTrack (a minimalist type of PRT) uses far less concrete and steel, and therefore costs far less to build.

The graph below shows relative costs of 5 configurations of guideway. Type 2, supported, is the type used by Taxi 2000 and generally costs the least to build. As you can see, spans of about 30 meters (90 feet) are most cost-effective.

The image below shows the relative sizes of PRT and Automate People Mover (APM) vehicles. While PRT cabs generally carry 4 or fewer passengers, APM vehicles carry 20 or more passengers.

The image below shows the size of the SkyTran flavor of PRT guideway relative to cars and buildings.

The image below shows the scale of another PRT flavor (J-Pods) compared to a freeway.

The images below show the size of PRT guideway (truss before cowling is attached) and bogey upon which passenger cabs are mounted.

The finished cab riding atop the truss structure with cowling attached.

Because PRT uses much less material resources and energy to transport passengers,
it also costs much less to build and operate.

Operations and Maintenance (O&M)

Savings in capital costs is reflected in Operations and Maintenance (O&M) of the system, which in the transit industry typically costs 3% to 5% of total capital costs. Thus, O&M for PRT should be proportionally lower in direct relation to lowered capital costs.

However, O&M for PRT should be much lower than industry standard for these 4 reasons:

  • Labor costs represent 70% of overhead in bus transit systems - a cost that is vastly reduced by using automated transit technologies. [The report "Viability of Personal Rapid Transit in New Jersey" estimated that O&M costs will be approximately half of bus and LRT costs; see Figure 22 - Operations and Maintenance Costs per Passenger Mile on page 58 (63 of the PDF).]
  • Insurance costs are significant for mass transit systems and may be dramatically reduced by employing PRT technology. A recent paper by J. Lutin et al reported that in 2011 alone, the US Bus Transit systems spent almost $500M settling liability claims resulting from accidents. When divided by the total US Bus Fleet size (not the number of buses involved in accidents) that translates into an annual liability exposure of $8,069 per bus! An entirely grade-separated PRT guideway would dramatically reduce the number of accidents and the attendant insurance costs -- as has been demonstrated by theme park rides. Theme parks, regulated by ASTM F24 standards, have an injury rate of 0.6 injuries per million patron rides, and only 171 deaths. Cars, on the other hand, have reported roughly 150 injuries per 100 Million miles, or 1.5 per million miles travelled, and actually kills about 40,000 people annually.
  • Maintenance costs are dramatically reduced due to the very few moving parts in electric vehicles such as a PRT cabs.
  • Fuel costs are reduced more than 50% due to small, light-weight vehicles with high-pressure tires rolling on a smooth surface without frequent stops and powered by inexpensive electricity.
All combined, PRT O&M is expected to be only 1% of capital investment, or $600,000 per year for the proposed $60M BART Circulator project. This 1% estimate is supported by the Automated Transit Network Feasibility Study for Clemson, Greenville and Mauldin (page 24) which states:
"The ATN system depicted in Figure 5.2 has 47 stations and 24.5 miles of elevated one-way track. Simulation indicates this system will require 76 GreenPods (including spares) in order to meet the 2022 peak demand. The capital cost of this system is estimated to be $253 M (about $10.3 M per mile) and the annual O&M costs are estimated to be $2.7 M."

Actual O&M costs of the Morgantown PRT system is $5M, which is 4% of the original cost of the system when built in the 1970's ($120M) -- or less than 1% of the inflation-adjusted cost of $570M. Vandalism, which is included in O&M, can be reduced by the inclusion of 1) video cameras at each station and 2) communications between each cab and security personnel (so problems can be promptly reported).

O&M, however, will depend upon the number of cabs in service. Adding more cabs will add more O&M costs. While 1% O&M may be possible at the low end of cab capacity, a PRT system with heavy demand could have O&M costs of 5% or more. While the capital costs go up as additional cabs are included, the cost of servicing those cabs will likely rise faster than the capital costs percentage represented by the additional cabs -- which run about 25% of total system costs according to the pie chart above. Also, O&M costs can be expected to be a higher percentage for very small systems due to costs of control and incident response personnel who are not fully occupied.

One PRT company publicly claims much lower costs than traditional mass transit (see page 17):

Transit X is anticipated to have operational costs of just a few cents per passenger kilometer – much lower than other modes of transportation. Labor and fuel make up the majority of operational expenses for most rail or bus systems. As Transit X is fully automated and solar-powered, there are no driver salaries or fuel costs.

Another PRT company has estimated operating costs at 4 cents per vehicle mile ($0.04/mi). that compares quite favorably with cars ($0.59/mi), buses ($8.10/mi), and commuter rail (like BART) which costs $18.91/mi. Even when passenger loading is considered, operating costs for cars, buses and rail are far higher than PRT. In addition to vehicle type and passenger counts, others measures (mpg, watt-hours, BTUs) are listed at the JPods website where PRT performs well on each metric.

Depending upon the control system used, there may be on-going annual costs. For example, one control system provider reportedly is willing to license their technology for $300 per year per vehicle.

Farebox recovery to pay for O&M is not pursued in the BART Circulator project for 5 reasons:

  • Adding fareboxes complicates the system design and adds equipment, testing and maintenance costs. Designing fare collection into the system, and preparing for it by installing wiring as appropriate, makes sense and will be done. Thus, fares can be implemented in the future. Doing so would provide a new, useful set of data on ridership and vandalism.
  • The wide divide we now have between rich and poor is toxic to the public welfare. Providing free transit for a portion of a trip helps reduce that divide for those with severe financial constraints -- and does so without the need for programs/prices designed for students and seniors. To address the equity imbalance in our area, free rides for all is a goal. If fares are introduced later, free rides could still be provided to Milpitas residents or a segment of the population (e.g. students and seniors).
  • Whether fares are charged or not, a $60M transportation infrastructure project will increase the property values in the area which will increase property-tax revenue to the City.
  • If the system expands beyond the Transit Area, the value of the system will rise exponentially with the number of stations. Thus, initially providing service for free will acquaint people with the value of the system. Then, adding fares later as the system grows will make sense to the public.
  • Given our Climate Emergency, encouraging as many people as possible to experience PRT and spread the good word during its first several years of operation is facilitated by free rides. As shown below, even a modest fare of $2 will likely reduce ridership by 40% (as shown on page 63 of the Greenville County Economic Development Corporation PERSONAL RAPID TRANSIT EVALUATION).

Here are operating costs in graphic form. At this point in time, the CO2 costs and resulting Climate Chaos are even more important than the financial costs.

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