- THIS PAGE IS WORK IN PROGRESS*

In versions of the calculator before 3.5.0 the number of bicycles, and the cost of bicycles, looks implausible. This page documents the new approach:

## Calibrating 2007

### Data

The National Travel Survey 2012^{[1]} reports:

- Table NTS0605 - The average distance traveled by bicycle per person in 2007 was 40 miles.
- Table NTS0608 - 42% of people aged 5+ owned a bicycle in 2011/12
- Table NTS0302 - 0.78% of non-air travel is by bicycle in 2012
- Table NTS0101 - 7103 miles travelled per person per year by all modes in 2007

COLBI - the European Bicycle Industry body - 2012 report on the European Bicycle Market ^{[2]} lists:

- Page 49 - 3771000 bicycles sold in GB in 2007, decreasing to 3600000 in 2012
- Page 50 - €725m value of bicycles sold in GB in 2007, increasing to €1098m in 2012.
- Page 21 - 2012 average bicycle price in GB €305, with NL highest at €724

The the british cycling economy report 2013^{[3]} contains:

- 2010 3.6million bikes sold
- 2010 Bike sales of £1.6bn
- 2010 Accessory & service sales of £0.9m

### Calculations

42% of people over 5 own a bicycle, and the over 5 population in the UK is 59 million, so in 2011/12 there were about 25 million bikes in the UK. This means ownership as a % of total population is about 42% * 95% = 40%.

The average distance per bicycle must be, approximately, the average distance per person divided by bicycle ownership: 40 miles per person / 42% bikes per person = 100 miles / bike = 153 km / bike.

If we assume no growth, so that bicycle sales replace broken bicycles, then 25 million bikes owned / 3.7 million bikes sold = average life of a bicycle of 7 years.

The average cost of a bike today is £250 (=€305). The operating cost is £30/yr (=£0.8m accessory and service sales / 26 million bicycles)

## What changes to 2050 as mode share changes

For the moment, we will leave the share of trips by Bicycle unchanged:

Level | % of total passenger-km, including aviation |

2007 | 0.5% |

2050 1 | 0.7% |

2050 2 | 0.9% |

2050 3 | 1.0% |

2050 4 | 4.7% |

Need to cross check whether this looks sensible against typical journey lengths and international comparisons.

Level 4: Lets assume that level 4 has 1 bicycle per person (roughly the case in the Netherlands)

In between, lets assume that bicycle ownership increases linearly with respect to increase in % of passenger km:

Level | % passenger km by bike | % bike ownership | Person-km/yr | Person-km by bike/yr | Bike-km | Bike-km / day |

2007 | 0.5% | 40% | 14,104 | 72 | 179 | 0.491 |

2050-1 | 0.7% | 43% | 15,363 | 108 | 252 | 0.689 |

2050-2 | 0.9% | 46% | 15,023 | 135 | 296 | 0.812 |

2050-3 | 1.0% | 47% | 15,023 | 150 | 319 | 0.874 |

2050-4 | 4.7% | 100% | 14,076 | 662 | 662 | 1.811 |

Assume that the cost range in 2050 goes from a high equal to the Netherlands £600 (=€724). Point estimate and low estimates are the same as today. (Note - another option would be to make the low equal to £160 (€190 the average selling price in Ireland) however, we decided to keep the lower level of £100 to give a bigger difference between high and low).

In any given scenario, assume that the ownership starts increasing from 2010.