First principles assessmentWhy introduce cycle lanes and other cycle priority measures?
This section is set out as follows:
Differences in cycling levels between countries
The table below gives an overview of the modal split in some European countries. Cycling tends to be more frequent in medium or smaller cities than in larger cities.
Transport modes for individual daily trips in selected European countries. Number of daily trips. Source: Solheim & Stangeby 1997
1 Trips longer than 200 m
The United States, unlike several European countries, does not have a long cycling tradition. However, cycling levels have increased significantly since the 1970s.
Annual US Bicycle Trips and Bicycle Mode Share, 1977- 1995 (NPTS, DoT)
There are great differences between countries in cycle share of modal split. The differences are due to different culture, history and cycling policy, elements that constitute peoples' habits over years. The following Danish quotations can illustrate this point:
"The bicycle is a national symbol for the Danes, as is the car for the Americans."
"The Danes are almost born cyclists – just like the Norwegians enter this world with skis on their feet." (Danish Road Directorate & Ministry of Transport 1989)
In addition, urban density and structure as well as climatic and topographic conditions in different countries will have an impact on the cycle share.
Will cycle lanes increase levels of cycling?
As noted above, there are a variety of explanations for the varying levels of cycling between countries. However, the evidence below indicates that investment in cycling infrastructure, and in particular the on-road network, has a part to play in encouraging cycling levels.
In the EU project WALCYNG (How to enhance WALking and CycliNG instead of shorter car trips, and to make these modes safer) people were asked to give their opinion on barriers to cycling and important measures to increase cycling. The figure "barriers to walking and cycling by modal category" below shows that nearly 50% of “walcers” (walkers and cyclists) mention lack of a sufficient on-road cycle network as a barrier for cycling (Stangeby 1997), whilst the equivalent figure for car drivers was over 50%. Among commuters in Norway 30% responded that cycle lanes [and routes] were the most important measure to stimulate cycling.
Barriers to cycling by modal category. Attitude surveys in Austria, Finland, Italy and Spain. Per cent.( Walcer= walkers + cyclists) Source: WALCYNG Stangeby 1997
Opinions on the most important improvements that can make people start using a cycle. Per cent. The Norwegian Marketing/SP-survey among commuters. Source: WALCYNG Stangeby 1997 (261 people surveyed)
Why encourage cycling?
Cycling is an environmentally friendly (clean and silent), healthy, cheap and flexible transport mode. In many European cities, cyclists lack space and other facilities and cycling induces conflicts with vehicles and pedestrians.
The table below provides a comparison of various transport modes from an ecological viewpoint with a private car for an identical journey with the same number of person kilometres. As can be seen, cycling compares extremely well with all other modes on every category. The figure for accident risk is far lower than that reflected in accident statistics. This is because the figure excludes accidents that are caused by collision with motorised modes. The figure therefore represents the intrinsic danger involved in cycling in a traffic-free environment.
Comparison of ecological impact of various modes for a journey involving a given number of person kilometres (European Commission 1999)
Cycling journey speeds
Cycling in urban areas is also efficient in terms of total journey speeds, as is illustrated by the table below. Cycling tends to be quicker than any other mode up to a journey length of 8 km. Clearly, the relative speeds will vary according to location and time of day.
Comparative Table of Journey Speeds in the Urban Environment (European commission, 1999)
Cycling is also a highly effective mode in combination with public transport. Assuming a cycling speed of 20 km an hour and a walking speed of 5 km an hour, cycling can increase the catchment area of a public transport interchange by a factor of 15. This means that 60% of the UK population live within 15 minutes cycle ride of a rail station (Gazey & Ades, 1998).
Health benefits of cycling
The figure below shows the impact that exercise levels have on mortality risk. The table shows the results of evidence from various sources on the impact of moderate exercise on the incidence of various diseases.
Effect on the relative mortality risk from changes in the level of physical activity (Ege & Krag, 2005)
Potential disease reduction by moderate exercise, in percent (Ege & Krag, 2005)
In many developed countries childhood obesity is becoming an ever more serious health problem. The figure below shows the prevalence of overweight children at 10 years old along with the levels of cycling in those countries. For the selected North European countries there is a strong negative correlation between these two criteria suggesting a correlation between cycling activity and lower childhood obesity.
Prevalence of overweight children and cycling levels in selected North European countries (Ege & Krag, 2005. Source DfT)
Comparison of exposure to pollution by car and by cycle
There are concerns that cycling in traffic will not be beneficial to health because of the exposure to emissions. There is no doubt that if possible it is healthier to cycle in traffic-free conditions. However, if the choice is between cycling in traffic or driving then the evidence seems to indicate that exposure is lower whilst cycling even after taking into account the cyclists' increased breathing rate. The results of a Dutch (top) and Danish (bottom) study are presented in the figure below. The explanation for cyclists’ exposure being significantly lower than that for car drivers is because cyclists tend to be situated on the edge of the road and at a higher level where pollutant concentrations are significantly lower than closer to the ground in the middle of the carriageway which is where the air intake for most vehicles is positioned.
Exposure to pollutants by bicycle and in a car (Ege & Krag, 2005)
Increasing levels of cycling improves safety
Cycle lanes and priority measures can be expected to significantly reduce accidents. The Institution of Highways and Transportation estimates that remedial works at junctions can reduce casualty rates by 30% to 60% (IHT, 1997).
Furthermore, increasing levels of cycling tend to be associated with lower pedestrian and cyclist deaths per inhabitant per year as is illustrated in the figure below. This indicates that absolute numbers of deaths to walkers and cyclists tend to drop as cycling levels increase. Measures that encourage cycling tend to improve safety for both pedestrians and cyclists. Furthermore, the presence of significant numbers of cyclists tends to improve awareness and reduce speeds of car drivers.
Modal share of cycling and pedestrian and cycle casualties (TfL, 2004)
Further evidence to this effect is shown in the examples illustrated below of Holland and Denmark where increases in the level of cycling have been accompanied by significant reductions in both the absolute number of accidents and accidents per kilometre cycle.
Increase in cycling levels and drop in the level of risk in the Netherlands 1980-1998 (Ege & Krag 2005)
Increase in cycling levels and drop in absolute numbers of serious injuries to cyclists in Denmark from 1990 to 2000 (Ege & Krag 2005)
In most countries cycling is significantly more dangerous than travelling by car. However, when cycling reaches levels seen in the Netherlands and Denmark the total accident risk is at least comparable. The table below compares the risk of driving and cycling. The figures have been corrected for two factors to create a more accurate comparison:
A further issue that should be noted regarding the statistics presented here is that killed and seriously injured statistics would be significantly higher for cycling compared to driving than these overall accident statistics. On the other hand, casualties per trip (arguably a more accurate comparison) would appear far more favourable to cycling. Furthermore, if child casualties were removed from the statistics (a category that does not exist for car drivers) then the casualty rates for cyclists would be reduced.
Comparison of Risk of accidents per million kilometres for motorists and cyclists in the Netherlands (European Commission, 1999)
Whatever method of comparison is chosen it is clear that health benefits significantly outweigh accident risks. Hillman has attempted to quantify this by weighing up the life-years gained by cyclists in Britain due to improved health, versus the life-years they lose through fatal injuries. He concluded that the health benefits of cycling, even in the relatively unsafe UK, outweigh the risks involved by a factor of around 20:1 (Hillman 1993). The British Medical Association drew similar general conclusions and stated that the "benefits [of cycling] to health…are frequently overlooked ... the British Medical Association highlights the significant contribution cycling can make to the nation's health and calls for radical changes in current transport policy"(BMA, 1992).
The responses to cycle lanes and priority measures are dependent on whether or not they are implemented as comprehensive network solutions and in combination with other measures (e.g. safe crossing points) that improve safety such as lower speed limits.
Short and long run demand responses
Cycle priorities may reduce the capacity for other traffic slightly, particularly at junctions.
If cycle lanes do succeed in encouraging mode shift from car then this may well have a positive impact on the road space that is available for other road users because cycles are significantly more efficient than private cars in terms of space efficiency.
The tables below are taken from London Cycling Design Standards. It should be noted that construction costs in London tend to be higher than the rest of the UK. Costs can be significantly reduced if a facility is implemented as part of other works such as road resurfacing.
Global Costs of Various Types of Cycle Facility (London)
Expected impact on key policy objectives
In countries that currently have a very low level of cycling, the contribution
to objectives that cycling is likely to make in the short-term is significantly
less than in countries with more cycling. This is because take-up of cycling
is a gradual process which tends to be particularly slow at lower levels
Expected impact on problems
Barriers to implementation