In public transportation, schedule adherence or on-time performance refers to the level of success of the service (such as a bus or train) remaining on the published schedule. On time performance, sometimes referred to as on time running, is normally expressed as a percentage, with a higher percentage meaning more vehicles are on time. The level of on time performance for many transport systems is a very important measure of the effectiveness of the system.

Background

On time performance is a measure of the ability of transport services to be on time. Almost all transportation systems have timetables, which describe when vehicles are to arrive at scheduled stops. Transport services have a higher utility where services run on time, as anyone planning on making use of the service can align their activities with that of the transport system. On time performance is particularly important where services are infrequent, and people need to plan to meet services.

The ability of different transport modes to meet on time performance statistics depends on the degree to which they are affected by external factors. For example, rail services often operate on a separated right of way, and so are not affected by road congestion. Buses, unless they are separated from road traffic, will be heavily affected by congestion.

To calculate the percentage of vehicles on time, comparison is needed with the timetable. A comparison is often completed for arrival time rather than departure time, but both are common. Departure times are normally more on-time than arrival times, as incidents and breakdowns occur that reduce the on time performance. When the comparison is made between the timetable, and the actual arrival or departure time, a rule is applied to determine how much of a deviation is permitted. For example, if a bus is 4 minutes 20 seconds late, a rules may be applied that a bus is only late when later than 5 minutes, so this service would be counted as on time. The choice of threshold for lateness is an important one, with a low threshold resulting in a lower on time performance statistic. A high threshold will result in more services on time, but may result in the managing corporation or government body being accused on not reporting correctly.

Passengers can be updated on the movement of transport vehicles with passenger information systems. These systems display the arrival time of vehicles to stops, stations or airports, and typical information displayed is the time in minutes to the next scheduled arrival. Some of these systems have been extended to include apps to show the movement of trains/buses/planes/ferries. Where services are delayed, more information can be provided, such as alternative transport options, or estimated time till services resume.

A small number of transport systems operate on the principle of go-when-full. This type of transport system will not have any meaningful measure of on time performance.

Airlines

Airlines are closely monitored on their on time performance. Numerous websites exist for reporting on punctuality for airlines, often operated by government departments.[1] Iraqi Airways, an airline, uses a rule that aircraft that depart within 15 minutes of scheduled departure are on time.[2] The 15 minutes rules for on time performance is commonly applied throughout the airline industry.[3] Airlines typically perform well when their on time performance reaches 90%.[4] OAG and Cirium regularly publish airline on time performance rankings and data.[5]

On time performance for aircraft is simple to calculate as aircraft depart and arrive at airports, and these are clear points to complete the on time performance calculation. Things are substantially less clear for bus services, where an on time performance can be calculated for each and every stop. One method is to calculate on time performance for only the start and end of the bus route, which can produce meaningful statistics. One problem with this method is where very large stops or interchanges are not at the start and end of the bus journey, but in the middle, and the start and end of the route are bus depots or other small stops for which on time performance statistics are not as important. In this situation on time performance may be calculated at the major interchange, rather than the start and end.

Buses

On bus services an on time performance can be calculated for each and every stop. One method is to calculate on time performance for only the start and end of the bus route, which can produce meaningful statistics. One problem with this method is where very large stops or interchanges are not at the start and end of the bus journey, but in the middle, and the start and end of the route are bus depots or other small stops for which on time performance statistics are not as important. In this situation on time performance may be calculated at the major interchange, rather than the start and end.


Bus routes are frequently late, given buses mix with road traffic. Bus rapid transit is bus based mass transit system, where road infrastructure has been specifically constructed to allow better on time performance, and more frequent and high speed services. This type of bus system is far less exposed to problem of low on time performance statistics than regular bus services. Trying to get to the school on time can be a big hassel for drivers. This results in 76 percent of schools in Ontario and Quebec to have late departures by chance not choice.

Light rail

Light rail, whilst being a rail system, can be exposed to problems with poor on time performance. This is especially the case where rail service operate in the middle of congested roads, and where a light rail system has a separate right of way the on time performance will be better.

Transport hubs

Users of transport systems often use several transport modes to complete a journey. They will change transport modes at a transport hub, and all transport modes have some kind of transport hub.

On time performance is important to interchanges. Where on time performance is poor, passengers or goods may miss a connection, and so be forced to wait. In some cases the transit time allowed from one transport mode to another may be very small, and so any lateness can result in services being missed. Where services are infrequent, such as a long distance train trip, or a flight, then the consequences of late services can be high. Transport systems that exist to deliver passengers and services to interchanges should be particularly concerned with achieving a good on time performance.

Measurement

Typically on time performance is measured by comparing each service with its schedule.[6] A threshold is chosen for how late a service can be before it is determined to be late.

on-time Performance

 

 

 

 

(1)

The scale of delays are often calculated in delay minutes.[7] A delay minute is the number of minutes a service is delayed multiplied by the number of passengers on board the transport vehicle.

passenger delay minutes

 

 

 

 

(2)

Network Rail, a large rail infrastructure provider in the UK, uses passenger delay minutes as a mechanism to reward and punish for services being on time and late respectively.[8] Using delay minutes as a measure allows for comparisons between heavily loaded large transport vehicles, and much smaller or lightly loaded vehicles. The economic cost of a large transport vehicle being delayed is much greater than a service that is almost empty.

Factors

There are many factors that can affect on-time performance.[9] Depending on the situation, the service may face regular delays or a service that usually performs on time may be occasionally behind schedule. Some of these factors include:

Effects of poor on-time performance

The effect of delays to a transport system are normally calculated as costs in dollars, either to the passengers, or to the transport provider. The transport provider will incur costs of the additional use of the vehicle, crew costs, and fuel.[13] In many cases the cost is calculated as a dollar value per minute. The total cost of delays for an entire transport system for one year can be very large.[14]

In many publications the effect of poor on time performance is equated to lost money. As passengers are delayed, this delay is equated to dollars, and this is the amount that is lost. Calculations are performed for the total amount "lost" per year for different countries, for example, for the US it was estimated that the cost to the country was $32.9 billion in 2007.[15] The total amount of cost per country per year can be very large.

An economic cost is calculated through the following formula:

Economic cost

 

 

 

 

(3)

The delay cost per minute is calculated as the addition of direct costs to a service provider, and the economic cost to passengers through lost time.[16] This is:

Delay cost per minute

 

 

 

 

(4)

The economic cost per minute for passengers is often expressed as a percentage of the average in the area.[17] For different transport modes the cost per minute may be different, as those using buses may have a lower income than those using trains.

Buses when late may experience a problem known as bus bunching. On some bus lines with a more frequent service, if one bus falls behind schedule passenger numbers waiting at bus stops may grow, required a longer layover time. One or more subsequent buses on the published schedule may pass these already cleared stops and have a nearly empty run, and may actually jump ahead of their scheduled time to the point that two or more buses are within close sight of one another. In some cases, one bus is able to pass another.[18] This phenomenon is sometimes known as clumping or bunching.[19] When this occurs, the even spacing of buses on the schedule may be severely disrupted, leading to extremely long waits for those attempting to catch a bus, and multiple buses arriving at once.[20] Bus bunching serves to reduce the effectiveness of buses as a transport mode.

Improving schedule adherence

Transit agencies often take the following measures in attempts to improve schedule adherence on their routes:

Real-world examples

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (March 2016)

The following chart shows some examples of real-world on-time performance. The figures are always (unless stated otherwise) per vehicle, not per customer.

Operator Mode of transport Period < 1' < 2' < 3' < 5' < 10' < 15' < 20' < 30' Comments Source
SBB All passenger rail 2014 87.7% [26]
Freight 77.2%
NS Passenger railway 2019 91.9% 92.6% 97.7% Measured at selected key stations [27]
Amtrak Passenger Railway 2008-2018

(average)

77% For trip length <250 miles train is late if >10 min [28]
Network Rail National Railway 2014 89.3% Commuter services are late >5 min, intercity >10 min [29]
Taiwan High Speed Rail High Speed Rail 2013 99.44% [30]
Lufthansa All flights 2014 84.7% [31]
Qantas Domestic Air Travel 2015 88.6% [32]
Cathay Pacific International Air Travel 2014 70.7% [33]
Yarra Trams Trams Jan 2016 86.7% [34]
Hong Kong MTR Metro (rail) 2015 to October 99.9% The threshold for on time is high at 8 minutes [35]
GO Transit Commuter Rail 2014-15 Fiscal Year 94% [36]
Buses 95%
SMRT Metro (rail) FY 2014 92.6% [37]
New York City Subway Metro (rail) 2018 65% [38]

See also

References

  1. ^ "Airlines on time statistics delays and causes". Bureau of Transport Statistics. Retrieved 6 March 2016.
  2. ^ "Virgin Australia Website". Retrieved February 21, 2016.
  3. ^ "Punctuality:How Airlines can Improve On time performance" (PDF). Booz Allen Hamilton. Retrieved 6 March 2016.
  4. ^ "Australian Business Traveller Website". Retrieved March 4, 2016.
  5. ^ Fox, Alison (January 31, 2022). "The Most On-time Airlines and Airports in the U.S. And Around the Globe". Travel + Leisure. Retrieved 2022-05-12.
  6. ^ "Why Amtrak on time performance is so much worse this year". Retrieved February 10, 2016.
  7. ^ "Flight delays cost $39.2 billion, passengers foot half the bill". Berkeley News. University of Berkeley. 18 October 2010. Retrieved 12 March 2016.
  8. ^ "Payments for disruption on the railway". Network Rail. Retrieved 12 March 2016.
  9. ^ Strathman, James; Hopper, Janet R. (April 1993). "Empirical Analysis of Bus Transit On Time Performance". Transportation Research Part A: Policy and Practice. 27 (2): 93–100. doi:10.1016/0965-8564(93)90065-S.
  10. ^ "Ferries: On Time performance Reporting" (PDF). Washington State Transport Commission. Retrieved 12 March 2016.
  11. ^ "Metra Website". Retrieved March 1, 2016.
  12. ^ "Ferries On-Time Performance Reporting" (PDF). Washington State Department of Transport. Retrieved 12 March 2016.
  13. ^ "Per minute cost of delays to US airlines". Retrieved 11 March 2016.
  14. ^ "Annual US Impact of Flight Delays". Airlines for America. Airlines for America. Retrieved 11 March 2016.
  15. ^ "Total Delay Impact Study" (PDF). Nextor. The National Centre for Excellence for Aviation Operations Research. Retrieved 12 March 2016.
  16. ^ "Standard Economic Value Guidelines" (PDF). Civil Aviation Safety Authority. Retrieved 12 March 2016.
  17. ^ "Standard Economic Value Guidelines" (PDF). Civil Aviation Safety Authority. Retrieved 12 March 2016.
  18. ^ "A Cure for Bus Bunching". ITS Berkeley. Retrieved 6 March 2016.
  19. ^ UOR_1.2
  20. ^ Debora MacKenzie (29 October 2009) “Why three buses come at once, and how to avoid it”, New Scientist. Retrieved 9 December 2014
  21. ^ Yang, Li (2013). "Achieving energy-efficiency and on-time performance with Driver Advisory Systems". Achieving energy efficiency and on time performance with driver advisory systems. IEEE International Conference on Intelligent Rail. pp. 13–18. doi:10.1109/ICIRT.2013.6696260. ISBN 978-1-4673-5277-2. S2CID 24300857.
  22. ^ "Punctuality:How Airlines can Improve On time performance" (PDF). Booz Allen Hamilton. Retrieved 6 March 2016.
  23. ^ "Punctuality:How Airlines can improve on time performance" (PDF). Booz Allen Hamilton. Retrieved 6 March 2016.
  24. ^ "Punctuality:How Airlines can Improve Performance" (PDF). Booz Allen Hamilton. Retrieved 11 March 2016.
  25. ^ "Transit Capacity and Quality of Service Manual" (PDF). Retrieved 11 March 2016.
  26. ^ "2014 Annual Report" (PDF). Swiss Federal Railways.
  27. ^ "ProRail performance monitor". ProRail.
  28. ^ "Amtrak On-Time Performance Trends and Hours of Delay by Cause". Bureau of Transportation Statistics.
  29. ^ "Network Rail websiter". Network Rail. Archived from the original on 2015-12-08. Retrieved 2016-03-05.
  30. ^ "2013 Annual report". Taiwan High Speed Rail Corp. 7 January 2015.
  31. ^ "Best Airlines and Airports for On Time Performance in 2014" (PDF). skift.
  32. ^ "Domestic Airline On Time Performance 2015" (PDF). Australian Government, Department of Infrastructure and Regional Development.
  33. ^ "Cathay Pacific Interim 2014 Report" (PDF). Cathay Pacific.
  34. ^ "Yarra Trams Monthly Report". Yarra Trams.
  35. ^ "Hong Kong MTR Press Release" (PDF). Hong Kong MTR.
  36. ^ "2015 July to Sept Quarterly report" (PDF). GO Transit.
  37. ^ "Singapore Financial year 2014 Annual Report" (PDF). SMRT.
  38. ^ Fitzsimmons, Emma G. (23 July 2018). "They Vowed to Fix the Subway a Year Ago. On-Time Rates Are Still Terrible". The New York Times.