Operations and Maintenance (O&M)
Mass transit is expensive to build and to operate. Annual O&M in the industry run between 3% and 5% of total capital costs. So, if a transit system is expensive to build, it will cost 3-5% of "expensive" every year to maintain it. Because PRT is light-weight and automated, the ITNS Business Plan estimates O&M costs at 3%. However, a case can be made that O&M costs could be as low as 1%.
O&M for just 1% of Capital Costs?
Author Tony Seba, a Stanford professor and guru of “disruption”, points out that an internal combustion engine drive-train contains about 2,000 parts, while an electric vehicle drive-train contains about 20. All other things being equal, a system with fewer moving parts will be more reliable than a system with more moving parts. And that rule of thumb appears to hold for cars. In 2006, the National Highway Transportation Safety Administration estimated that the average vehicle, built solely on internal combustion engines, lasts 150,000 miles. Current estimates for the lifetime of today’s electric vehicles are over 500,000 miles. As Seth Miller points out, "The total cost of owning an electric vehicle is, over its entire life, roughly 1/4 to 1/3 the cost of a gasoline-powered vehicle."
In addition to using an electric drive system, the ITNS design uses captive vehicles that cannot leave the guideway. Dual-mode vehicles like those at Heathrow Airport are designed to also drive on city streets, which requires many more parts (e.g. steering, safety features, and battery pack), not to mention the far more complex programming required to maintain safety.
One example of the ITNS design is the stainless steel chassis. Designed for a lifetime of 20 years, it can be expected to travel 1,600,000 miles. Designing a system that meets required performance with minimum life-cycle cost, as ITNS has done, also leads to a more sustainable mode of transportation.
With appropriate preventative maintenance, both repair costs and service interruptions go down. Thus, both financial and service-level goals dictate that preventative maintenance be a high priority.
A small vehicle chassis rolls within the guideway - carrying the passenger cabin atop.
Small vehicle chassis supports and moves passenger cabin.
While transit industry O&M typically costs 3% to 5% of total capital costs, O&M for PRT should be much lower for these 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.]
- 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, 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 used in a PRT system.
- 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.
Fuel Costs and Carbon Pollution
PRT energy consumption is exemplified by the bar chart on page 23 of the ITNS Business Plan which shows “ENERGY USE, kW-hr/pass-mile for various transit modes. PRT is near the bottom with 0.6; at 0.5 is the lowest “Van Pool with high vehicle occupancy”, with Light Rail at 3.0.
This is a different scale (kW-hr/pass-mile) than used in the graphic “Comparing the Carbon Footprint of Transportation Options (shown here) which measures the carbon footprint of transportation in grams of carbon dioxide (CO2) equivalents emitted per person to travel one kilometer (CO2e/pass-Km).
Page 224 of Contributions to the Development of Personal Rapid Transit uses yet another scale: mpg of gasoline on a per rider basis. Background information for the bar chart is at Anderson, J. E. "What Determines Transit Energy Use, Journal of Advanced Transportation, 22:2 (1988), pp. 108-132. Page 30 of the document shows Electrical Energy Use that ranges from 130 Watt-hrs/passenger mile at 15 mph to 650 Watt-hrs/pass-mile at 60 mph. Also on page 30 is a chart showing the miles-per-gallon-equivalent for PRT speeds ranging from 15 mph (118 mpge) to 60 mph (30 mpge).
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.
Maintain a 50-year old system?
Nearly 50 years ago, a PRT wannabe system was built at the Morgantown campus of West Virginia University (WVU). Since then, it has delivered 80 million with no serious injuries or fatalities. This long-term experience gives us actual O&M costs for the Morgantown PRT system of $5M each year. That $5M is 4% of the original cost of the system when built in the 1970's for $120M -- or less than 1% of the inflation-adjusted cost of $570M.
While similar low-cost O&M costs can be expected in Milpitas, costs will also 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 expect higher O&M costs, even if just for cleaning. Also, O&M costs as a function of number of vehicles may be higher for very small systems due to fixed costs of control and incident response personnel who are not fully occupied. By keeping good records, LoopWorks expects to answer many questions regarding O&M costs.
The ITNS hardware design chosen by LoopWorks is derived from the Taxi 2000 technology which was evaluated in a 2004 report by TRANSEK Consultants for the project entitled EDICT project. Included in the report (page 4) is this chart comparing O&M costs per passenger-kilometer between Bus, PRT, LRT and AGS (Automated Guideway Systems or "APM" in the US). Figures come from published reports for the different systems in the early 2000's. Bars in blueish are Stockholm systems, in green are PRT systems, and in red/brown are other systems.
From the report: "An average of the three PRT systems yields an operating and maintenance cost of 0.10 Euro per passenger-kilometer. The average operating & maintenance costs for all the other systems (AGT/LRT; Bus, Metro and Commuter rail systems) are 70% more expensive to operate than for the PRT system."
Of all the costs for the various transit modes, one can see that LoopWorks (Taxi 2000) is the lowest-cost option and costs much less than other options. Assuming that the relative cost relationship is still true, then the estimated ratio of 6:21 (29%) applied to the operating costs of VTA's LRT system yields another estimate of PRT O&M costs.
If we start with the Taxi 2000 cost of 0.06 M€ per passenger-kilometer (0.096 M€/mile),
use the 2004 date-of-publication conversion rate of 1.2 dollars per Euro ($0.115/mile),
and factor in a 36.6% cumulative inflation rate from 2004 to 2020,
current passenger-mile costs are estimated at $0.16/mile.
Other Factors Impacting O&M
At the high end of O&M estimates is that provided in the ITNS Business Plan. In addition to details on the costs of system components, page 36 offers a total O&M cost for an example 36-mile system at $0.33 per passenger-mile, and 3.35% of "Annual O&M as a fraction of capital cost".
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).
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.