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Travel reduction and teleworking:
what we know 
and what we don't

Two of the reports reviewed in Issues section of Flexibility consider the traffic/teleworking equation.

The study commissioned by the Dublin Transportation Office and its partners looks at the possibilities of tackling the city's traffic congestion by encouraging telecommuting. And the study from the LGMB, Teleworking and Local Government, has a chapter on traffic reduction, surveying recent research and outlining the "what ifs" which the authors feel could limit or cancel out any benefits.

This article by Andy Lake, who led the 1997 study in the Cambridge (UK) area, commissioned by the UK Department of Environment, Transport and the Regions, surveys recent research, summarises the key issues and highlights the opportunities both for companies and for public policy development.

Travel substitution - an introduction

The case for teleworking  is fairly well established in terms of the business benefits it can bring. By teleworking we mean having a more flexible approach to the location of work by taking advantage of the new information and communications technologies (ICT).

More contentious is whether teleworking can also achieve significant overall reductions in traffic. If it can, there are clear benefits to the environment. There are also benefits to business if reductions to in-work as well as commute mileage can be achieved. And with the CBI estimating that congestion costs UK industry some £15-20 billion per year, any reduction in congestion must also be welcome1.

That teleworking has a direct traffic substitution effect is fairly well established. If a worker is not travelling to work, or not travelling so far, it is clear and measurable that less miles are being travelled for work purposes. Savings to the individual and organisation can be measured, and weighed against other costs. Benefits are widely reported in case studies, pilot evaluations and more formal research. 

The overall picture, however, is not so clear. While specific reductions are identifiable, it is not clear whether there might not be new traffic generated, either "filling the space" in trips removed from congested areas, or generated elsewhere. There are many "what ifs". 

This article attempts to summarise "what we know and what we don't", and to provide an introduction to the research and the issues.

The "new transport agenda"

With the UK government’s White Paper on Transport published in the summer of 1998, there’s a new climate of thinking in transport planning. It emphasises concepts such as sustainability and the need to promote environmentally friendly forms of transport. The government and environmental organisations are mainly thinking in terms of persuading people to change the way they travel to reduce the use of the private car. There is also a developing focus on trying to get freight back on the rails.

"Transport substitution", however, is a concept only just beginning to gain currency: that is, replacing some journeys altogether through use of the new ICT.

In essence, the UK government’s agenda revolves around the question:

  • "Why not change the way we travel?"

while transport substitution asks:

  • "Why not change the way we work?"
  • "Why not change the way we shop?"
  • "Why not change the way we have (other kinds of) fun?"
  • "Why not change the way we send things?"

In posing these questions, which reflect the capabilities of the ICT, the issues are taken beyond the normal realms of transport planners and engineers. These areas are not only inter-disciplinary, but also at present only thinly researched.

One interesting study into the transport effects of ICT published in 1996 was commissioned by Autoglass, who presumably have an interest in keeping as many windscreens on the road as possible. Based on studies such as those by BT and the Henley Centre, it projects reductions in the number of car journeys as follows:





% reduction

Total trips per week per person

637 million

400 million


Source: Motoring 2010; The end of the road? (1996)

This is based on projected growth in home shopping and community, entertainment and financial services, as well as increased telecommuting. The figures for reductions in travelling to work are as follows:





% reduction

Work trips per week per person

328 million

186 million


Source: Motoring 2010; The end of the road? (1996)

This projected reduction of 142 million trips per year represents a reduction amongst individual commuters from 10 trips per week to 5.7 trips per week – just over 2 days per week on average teleworking2.

Similar conclusions have been produced in a study commissioned by another motor industry organisation, the RAC. The RAC study, based on work by National Economic Research Associates, Herriot Watt University and Critical Research, concludes that by 2007

    • teleworking will cut commuter traffic by a fifth
    • videoconferencing will cut business travel by a fifth
    • use of IT will cut lorry journeys by a fifth
    • new communications will cut shopping travel by one sixth3.

These figures, in terms of absolute numbers, appear to be rather high, and projecting similar travel behaviour onto the whole workforce begs numerous questions.

A much more cautious view was put forward by the Review of Telework in Britain, commissioned by the Parliamentary Office of Science and Technology in 1995 as a survey of telework research. On travel reduction, it concluded:

"home-based teleworking has been found to reduce the number of commute trips undertaken by workers – the best available estimates for the UK suggest that, in 1993, teleworking reduced total UK miles by some 1% and that the long-term potential is for some 5-12% of total car use to be substituted by telecommuting"4.

Similarly, the study in the Dublin area of Ireland, adopting a "current practice" approach rather than trying to incorporate projected changes in technology and work behaviour, finds a less than 1% substitution effect with only 1.5% potential for 20165.

Cutting traffic by changing the way we work

The Dublin study, like many others, focuses on individuals and individual jobs rather than on work tasks and behaviours. 

In 1997 HOP and Hague Consulting Group (transport analysts) carried out a study for the DETR, Assessing the Impact of Advanced Telecommunications on Work-related Travel.

The aim of this study was to identify the types of work which, in a large organisation, could most effectively be carried out on a "location independent" basis, and then to quantify the resulting traffic effects if the new ways of working were to be put into practice. Cambridgeshire County Council acted as the test site for the study. All forms of telecommunication-enabled work were considered: home-based telework, telecentres, mobile teleworking, videoconferencing, electronic data sharing, remote diagnostics and monitoring etc.

A central premise of the study is that employers are unlikely to introduce new ways of "wired" working for their potential environmental benefits. Rather, they would be prompted to introduce new ways of working for their business benefits, with any environmental benefits a welcome spin-off. 

It was also anticipated, and the results bore this out, that most workers would be able to work from alternative locations for only a limited amount of the working week. Exploring work and travel behaviour along these lines gave this study, we felt, an air of realism which may be lacking in some of the more upbeat surveys driven by telecommunications interests or "teleworking evangelists".

The study concluded that if employers in the Cambridge area adopted the various forms of teleworking for suitable tasks, the traffic effects would be a 4%-8% reduction in traffic across the day, with considerably greater reductions in the morning and evening peaks.

To put this into context, this reduction would be wiped out by the end of the Millennium by the projected increase in traffic, if the government’s forecast of growth rates are correct.

Home-based telework and local telework centres 

Most research has shown that there are very significant net savings to be made in terms of hours and miles travelled, plus reductions in vehicle emissions, by those who are able to work at home or closer to home at a telecentre.

One of the first substantial pieces of research quantifying traffic effects was the 1995 US study Telecommuting Centers and Related Concepts. This found that

"The number of commute person-miles saved per center usage ranges from 38.5 to 150 with an average of 93.4 miles. This compares to an average of 36.1 commute person-miles saved per telecommuting occasion for home-based telecommuters. The implication is that the telecenter users studied travel more than twice as far to the usual work place than home-based telecommuters, who already live about twice as far from work as the average commuter"6.

That teleworking appeals more to those who live further away from the workplace was also confirmed in our own study. Patricia Mokhtarian and her co-researchers in the US have subsequently become more sceptical about the overall potential of telecommuting/teleworking to reduce car-borne travel, due to the effects of latent demand.

However, the results of telecentre pilots set up by UK local authorities are broadly in line with the earlier US findings. For example, an evaluation of the traffic reduction effects of Surrey County Council’s Epsom telecentre concludes that:

"with the introduction of the Telecentre the average length of each car journey from home to work falls by approximately 19% to 13 miles……. the average duration of each car journey from home to work falls by approximately 36% to 30 minutes….. Based on current Telecentre usage, there is a travel distance saving of 30,000 vehicle miles or 48,300 vehicle kms per year"7.

Similarly, teleworking at Hertfordshire County Council Trading Standards has produced significant traffic reductions. The focus here has been on reducing business miles travelled:

"In-work travel time has reduced by a healthy 10%, with the in-work miles (reimbursed) reduced by 9,000, representing between 5-8% reduction. Personal miles have also reduced, with staff who used to be based in the office on the other side of the County reporting personal savings despite their increased distance from the office".

It is also reported at Hertfordshire that:

"Staff who live near the new office tend to be in more (2-3 days a week) than those who are distant (1 day a week). Where previously staff used to start and finish in the office, all peripatetic staff tend to group appointments and go from and return direct to home"8.

This gives some idea of some of the travel behaviour involved in achieving these reductions in travel. But key for all the teleworking evaluations are the reported benefits in terms of productivity – i.e. the work that is done more effectively, and the extra work that is done in the time saved by not travelling.

Latent demand

There is a fear that the benefits, however real to the individual or company, will not add up to any substantial environmental benefit at the end of the day.

The key issues here are:

  • To what extent will latent demand be realised by other road users taking advantage of "liberated" road space?
  • To what extent will other trips be made by the home/telecentre worker during the course of the day that would otherwise not have been, or by other family members using the car?
  • How proportionately will transport substitution affect different traffic modes?
  • Will ICTs in due course affect location decisions so that people will tend to live further from their places of work, and therefore make fewer, but longer trips?

The effects of teleworking on public transport will vary from place to place. For example, in Cambridgeshire where, starting from a low base, public transport has all but disappeared since deregulation, the majority of people adopting teleworking would probably be car drivers or cyclists (cycling accounts for 25% of journeys to work in Cambridge).

A study in San Diego found no overall change in mode split before and after introduction of teleworking9. A study in the Netherlands, on the other hand, found that teleworking nearly always replaced trips by bicycle and public transport. It did not reduce car travel and resulted in a shift in mode split towards the car10. The Dublin study referred to also found significant mode shift away from public transport by suburban train, though less so from buses.

A possible explanation is that trips by public transport are usually less convenient, and therefore most likely to be substituted; this is supported by arguments from Gillespie11 et al and Salomon12. However, there are wider issues of the attractiveness, regularity and convenience of public transport which need to be addressed with or without teleworking, and the question of possible further restrictions on private car use.

One irony here is that if the government is successful in promoting environmentally friendly transport, it is perhaps more likely to be these types of journey that will be hit more by transport substitution.

Less or more in-work miles?

In our recently completed study for the DETR, focusing on changing the way a large public sector employer works, we identified the savings in business mileage and hours as being in the order of between 25% and 50% of the potential reduction in commute miles (depending on the levels of uptake of new ways of working)13.

One study in the Netherlands estimates a maximum transport substitution effect in business miles of 35%. However, the authors go on to say that there may be new trips or longer trips generated which may largely negate or even outweigh the direct traffic reduction effects14.

This viewpoint is gaining some wide currency, although it is based on only very limited empirical data. It is to some extent supported, however, by some case studies particularly relating to mobile workers. Where, for example, numbers of client visits are an indicator of productivity, the elimination of visits back to base by using telecommunications can allow for the fitting in of several further trips per day.

It is here that a somewhat more sophisticated analysis of types of journeys is needed, and of the technologies that might be used to enable trip substitution, as was included in the HOP/Hague research.

Dealing with the "what ifs" 

It is clear more research needs to be done to assess the more complex issues of latent demand.

But it is very important not to fall into the trap (as some researchers have done) of seeing the "what ifs" as cancelling out the identified benefits. Those benefits may still remain - to an individual, a company, to the local environment - even if future research finds that other or longer trips replace those that have been replaced by telecommunication.

For comparison, take the example of the setting up of a Park and Ride scheme. Some research has indicated that Park and Ride can generate new car trips. That is, some people will take to their cars to drive to a Park and Ride site on the edge of a town, where previously they would have done the whole trip by public transport. Even so, for most other users of the site, a car trip into town has been eliminated, and the intended localised benefit remains.

Policy makers need to concentrate on achieving benefits they can control and measure, rather than dwelling on the unknown. Similarly employers can measure the financial savings and increases in productivity, even if other employers do not follow suit.

And it cannot be assumed that research into the wider picture will show traffic increase to balance against the measured reductions. What we don't yet know, we don't know. The traffic effects of these "what ifs" have to be assumed to be neutral until it is shown to be otherwise. And the evidence either way is scant so far.

Conclusions – is it worth it?

Many of the issues raised concerning latent demand are as yet some way from resolution. Research of implemented schemes over a number of years is necessary before we can have any clear idea of the effects, and even then it will be difficult to isolate the effects of teleworking from other causes of traffic generation.

However, on balance there is cause for seeing teleworking as a positive force for reducing traffic, as long as one does not expect too much. It is not a magic wand. However, it should be seen as one instrument of policy in the new transport agenda. On its own transport substitution through the use of ICT will deliver only modest reductions in overall traffic levels for 3 basic reasons:

  • Work-related trips are only around half of all trips by car
  • Probably only about 30-40% of work can effectively be done on a flexible location basis
  • It is possible/likely that other (as yet unquantifiable) trips will be generated.

That said, there could be significant benefits to the environment if the government and highway authorities promote "working down the wire rather than down the road" as part of a package of traffic demand management measures. The research shows it is workers with difficult journeys (either because of length or congestion) that are the most willing to take up flexible working. Ensuring that there is no incentive to travel by car in terms of convenience or cost will be the best way to reduce the counter-effects of latent demand.

Meanwhile for employers the good news is likely to be in finding a tool for reducing the costs of travelling to meetings and of service delivery, and in having some of their employees less stressed out by the daily commute.


1 CBI (1998) Roads to the Market; economic instruments in an integrated transport policy. A CBI (Confederation of British Industry) discussion document published in March 1998. 

2 Freeman, V (1996) Motoring 2010: The End of the Road? Report commissioned by Autoglass

3 NERA (1997) Motors or Modems? Virtual travel becomes a reality. Report commissioned by the RAC

4 Gillespie, A, R Richardson, and J Cornford (1995), Review of Telework in Britain: Implications for Public Policy. Centre for Urban and Regional Development Studies, University of Newcastle upon Tyne (prepared for the Parliamentary Office of Science and Technology).

5 Amárach Consulting (1999) Telecommuting: The shortest route to work. Study commissioned by Dublin Transportation Office

6 Bagley, Mannering and Mokhtarian, (1994) Telecommuting Centres and Related Concepts. University of California Institute of Transportation Studies.

7 The evaluation is available on the Internet at 

8 Case study in Flexibility 

9 Mokhtarian, PL, SL Handy and I Salomon (1995), Methodological issues in the estimation of the travel, energy, and air quality impacts of telecommuting. Transportation Research, 29A(4), pp 283-302.

10 Hamer, R, E Kroes and H van Ooststroom (1991), Teleworking in the Netherlands: an evaluation of changes in travel behaviour. Transportation, 18(4), pp 365-382.

11 Op cit, see note 4

12 Salomon, I (1994), How much telecommuting should we count on? A forecast for Tel-Aviv in 2020. Transportation Research Record 1463, pp 26-34

13 Home Office Partnership & Hague Consulting Group (1997) Assessing the Impact of Advanced Telecommunications on Work-related Travel. Study commissioned by the Department of the Environment, Transport and the regions, under the Seedcorn programme.

14 Van Ommeren, K, R-J Voorn and T van der Hoorn (1997), The information society as booster or substitute for business travel.  Proceedings Colloquium Vervoersplanologisch Speurwerk, Rotterdam, 1997, pp 785-796 (in Dutch).





}  In essence, the UK government’s agenda revolves around the question:

"Why not change the way we travel?"

while transport substitution asks:

"Why not change the way we work?"

"Why not change the way we shop?"

"Why not change the way we have (other kinds of) fun?"

"Why not change the way we send things?"



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