Evidence from excluded studies
| Category of intervention | Included studies | Summary of findings from included studies* | Excluded studies | Primary reasons for exclusion† | Summary of findings from excluded studies* | Comparison with included studies |
|---|---|---|---|---|---|---|
| *These are the reviewers’ summaries, not those of the authors of the primary studies, except where shown in inverted commas—in which case the quoted data constitute the relevant outcome data reported by the authors and do not require further summary. †Studies were excluded because the study design did not meet final inclusion criteria, because the study population did not meet the final inclusion criteria, or because they fulfilled these criteria but provided inadequate information about methods, results, or both. Some studies failed more than one criterion. | ||||||
| Targeted behaviour change programmes | One randomised trial, three controlled prospective studies of the same intervention in different settings, and two uncontrolled prospective studies | Modal shift in motivated subgroups (five out of six studies) | One uncontrolled prospective study of advising patients to take more exercise | Population | Both identified potential for modal shift | Consistent |
| One pilot study of targeted information for households and commuters | Information | |||||
| Agents of change and publicity campaigns | One randomised controlled trial of school travel coordinators | Small modal shift in only one relatively weak study out of four | One case study of a travel management association | Design | “Inability to achieve any significant shift in travel behaviour” | Consistent |
| One controlled prospective and two uncontrolled prospective studies of publicity campaigns | Two studies of sustainable transport campaigns, one uncontrolled prospective and one controlled retrospective | Information | Both suggested substantial modal shift | Contradictory, but of unknown validity | ||
| Health walks | No included studies | — | Two uncontrolled retrospective studies of participants | Design | About a quarter of participants claimed to have changed their travel behaviour | Additional category of intervention with potential for positive effect—requires further research |
| Cycling promotion | One uncontrolled prospective study (also included in the group of targeted behaviour change programmes above) | Intensive targeted programme including free bike produced a modal shift | Two uncontrolled retrospective studies of free workplace bikes plus local infrastructural improvements | Design | Both identified the potential for modal shift | Consistent |
| One uncontrolled prospective study of promoting cycling for shopping | Population | No evidence of modal shift | Additional category of intervention with no evidence of positive effect | |||
| Networks of routes for cyclists and pedestrians | One controlled prospective study and two uncontrolled prospective studies | Increase in cycling mode share (only) in only one of three studies | Five studies, all either case studies reported with scant detail or based on vehicle counts | Design (4) Population (1) | One study based on vehicle counts reported increases in cycling, but no data on walking; the others showed no evidence of modal shift | Consistent |
| Traffic restraint | Three uncontrolled prospective studies: one of city centre traffic restraint, one of bypasses and one of 20 mph (30 km/h) zones | Small modal shift in only one of three studies | One uncontrolled retrospective study of neighbourhood traffic calming schemes | Design | Small proportions of residents claimed to have changed their travel behaviour | Consistent overall |
| Seven studies of a variety of urban traffic restraint schemes, either using unclear or case study designs or based on vehicle counts or shoppers | Design (3) Population (4) | Most showed no clear evidence of modal shift; where a modal shift was demonstrated, it was only among weekend city centre shoppers | ||||
| Two uncontrolled prospective, or partially-prospective, studies of drivers’ trips across road bridges | Population | Small proportions claimed to have shifted mode after the bridge was closed | ||||
| Four studies (one controlled prospective and three uncontrolled prospective) which were reported with scant detail or which conflated bike and moped trips | Information | Impossible to assess | ||||
| Road user charging | One uncontrolled prospective study | No evidence of modal shift | One pilot study of the effect of an in-car charging unit on commuting journeys | Information | “Another peak-period alternative for two of the sample was cycling” | Consistent— no clear quantification of modal shift |
| Parking charges | No included studies | – | One uncontrolled prospective study of town centre parking charges | Information | Identified potential for modal shift among commuters, but not among residents | Additional category of intervention with potential for positive effect — requires further research |
| One uncontrolled retrospective study of parking charges at government workplaces | Design | No overall modal shift | ||||
| Fuel rationing | No included studies | – | One uncontrolled retrospective study of changes to car trips after introduction of fuel rationing | Design | Identified potential for substantial modal shift | Additional category of intervention with potential for positive effect — requires further research |
| Providing alternative services | One uncontrolled prospective study of a new railway station | Modal shift in only one of three studies | One uncontrolled retrospective study of introducing a passenger only commuter ferry | Design | Not designed to collect relevant outcome data | Consistent — no clear quantification of modal shift |
| One controlled prospective study of a car sharing club | ||||||
| One controlled retrospective study of neighbourhood telecommuting centres | ||||||
| Multifaceted urban transport policies | No included studies | – | Thirteen case studies of trends in mode share in cities where multifaceted transport policies had been enacted over a long period | Design | Three cities reported a modal shift for trips to the city centre only, but in two of these cities there was no modal shift in residents’ trips overall. All other cities reported zero or negative shifts | Additional category of intervention with potential for positive effect — requires further research |