Measuring performance

We measure network performance by comparing the number of kilometres a route has done in the last quarter.

We compare each quarter to the same quarter of the previous year, rather than the last quarter of the same year. This is because factors affecting performance, like traffic conditions, can vary depending on the time of year, so this system makes it possible to identify underlying trends.

Scheduled kilometres may not be met because journeys are cancelled or suspended due to:

  • Traffic congestion
  • Staff availability
  • Engineering problems or mechanical breakdown

Quality of service indicators (QSI) are used to monitor service reliability.

Customer satisfaction

We ask a sample of passengers to give a score out of 100 on a wide range of bus service features, based on the journey they have just made. Passengers are carefully selected each quarter to represent all bus passengers in London.

Recent figures can be found in the latest quarter summary document below.

Defining the passenger journey

A passenger journey is defined as one ride on a single vehicle - not a bus trip from A to B as this may include more than one bus ride.

Statistics include all London Buses' contracted services but exclude any non-scheduled kilometres, London Service Permit routes and other special services.

Bus speeds reports

We monitor the speeds of buses to understand the impacts of changing road network conditions. Bus speeds include time spent stationary (for example at traffic lights and at bus stops). Bus speeds are available for the entire network, by borough, and by route.

  • All data is in miles per hour
  • All AM data is taken for Mondays to Fridays, School and Non School days, between 07:00 and 10:00
  • At Route level, some routes may be appear twice. This is because a service change happened during a period. A service change may include a change to a route structure, contract or operator

Factors affecting performance

Quarter 1 2018/19: 1 April 2018 to 22 June 2018

Results improved slightly compared with Q1 a year ago, with losses due to traffic delays continuing at the lowest levels seen for twenty years. Included in the reasons for this are improved operating conditions arising from a reduction in roadworks, improved signal timings and a slowing of economic growth. Events causing significant delays to buses this quarter included a series of burst water mains which in two cases prevented buses from leaving their garages and Central London gas works. Whilst rainfall has been lower than usual there were several incidents of localised flooding during the quarter. Lost kilometres due to mechanical and staff reasons were also slightly improved compared with a year ago.

Until this 2017/18, bus speeds had been in consistent decline. The deterioration has started to reverse over the past year, although speeds remain much slower than in 2014. Bus speeds in Q1 were very slightly slower compared with a year ago predominantly due to routes in Outer London with Inner London showing little change.

Compared with Q1 a year ago, EWT has improved slightly and is therefore showing some of the best ever results. Inner NE and NW London have shown a particular improvement whilst the Outer SW area had deteriorated slightly. Punctuality of low frequency services was slightly worse than the same quarter a year ago, as was night bus performance.

International Bus Benchmarking Group

London is a member of the International Bus Benchmarking Group (IBBG), an international knowledge sharing network of bus companies. It was established in 2004 and is facilitated by Imperial College London.

Benchmarking is a continuous systematic process for evaluating the products, services, processes or organisations that are recognised as representing best practice for the purpose of organisational improvement. A blend of operational and customer metrics are used to track the performance of the bus network.

Every year, a review of buses performance monitoring is evaluated internally and presented to TfL's Independent Investment Programme Advisory Group (IIPAG) by Imperial College London to justify expenditure and ensure quality of service provided to passengers.