Just travelling? Changing Paradigm for Urban and Mobility Planners

Given the fact today that travel time is the main driver in Cost Benefit Analysis, how can we properly evaluate the social interest of projects aiming to improve mobility for pedestrians, bikes and the urban landscape, while also restricting the use of cars in cities, considering that these projects are most likely going to increase travel time for a large number of users?
How to adjust decision models for mobility planners?

• It has been proven in some cities that up to 30% of motorized trips may diminish after a measure of reducing street capacity for cars.

• Today, transport policies are increasingly applied aiming to reduce the social and environmental impacts of transport and to improve the quality of the urban environment and landscape while reducing emissions of pollutants endangering public health.

• The value attributed to land today obtained for use by pedestrians, bicycles or public transport should be greater than or equal to the higher costs passed on to drivers of private vehicles, as long as traffic is not degraded below the level of service indicating increased congestion.

• It is important to consider the value of mobility and transport policies that can play in favour of better public health and conviviality, which are the main objectives of most urban mobility plans being currently brought forward.

• Policies and investments in transport infrastructure and services since the 60s have been designed to increase overall capacities of the transport system, frequencies and speed of services.

Policies and investments in transport infrastructure and services since the 60s have been designed to increase overall capacities of the transport system, frequencies and speed of services. The most common assessment method in developed countries was to measure the efficiency of investments in terms of cost-benefit analysis (CBA). The value of time savings for travellers has long been regarded as the most important social benefit, often accounting for up to 80% of the benefits attributed to a transportation project.

But today, transport policies are increasingly applied aiming to reduce the social and environmental impacts of transport and to improve the quality of the urban environment and landscape while reducing emissions of pollutants endangering public health.

  • In suburban areas, for instance, maximum motorway speeds are lowered in major city accesses to reduce the number of accidents and the levels of emissions.
  • In city centres, urban mobility plans increasingly support preference for pedestrians by removing cars from historical streets, enlarge walkways, trace new bicycle lanes and extend bus lanes, overall reducing public space dedicated to circulation.
  • Tolls and congestion charges have been applied in cities like London, Oslo and Milan. In many cities, old motorway links into the city centre have been demolished, giving way to the redevelopment of former urban freeways.

The conventional methods and evaluation criteria should be redefined according to the new emerging social and political values backing-up local mobility policies. These changes result from the evolution of social behaviour linked to generational changes, and to the emergence of new information technologies and communication. The application of conventional CBA criteria, which overestimate the time savings over other social and environmental benefits, could lead to the paradox of positively evaluating measures such as removing bike or bus lanes, or sidewalk widths, just to provide more traffic lanes.

In particular, it is necessary to adjust the value of travel time considering, for example, if comfort during travel allows the user to carry out other activities, or if information in real time allows users to adjust their travel plans to a greater extent. More importantly, the value of mobility and transport policies that can play in favour of better public health and conviviality should be considered, as these are the main objectives of most urban mobility plans currently being brought forward.

  • In relation to conviviality, public transport and urban public spaces enable casual encounters and interaction between people of all kinds; increased space designated solely for walking/pedestrian areas has an inherent social value, especially in cities that tend to have more diverse population profiles.
  • In relation to public health, the influence of air pollution on cardiovascular and respiratory diseases has been measured in recent studies across Europe, claiming for political action.

It can be considered that a decrease in road capacity, for example derived from the widening of walkways of some streets, reduces traffic flow and speed, therefore increasing overall costs of motorized traffic; or that drivers change their routes, which thereby result in increased time loss due to increased journey distance, increased fuel consumption and other operating costs. We also produce indirect costs on the residents of the streets affected more in terms of noise and pollution, particularly in the streets increasing their traffic.

Eventually the number of motorized trips may tend to decrease because travellers having to face such higher costs leave the car in favour of public transport (but it is likely this will be only a small number).

It is also likely that affected drivers increasingly make a more rational use of their vehicle, using a single journey to carry out several activities or adjusting travel times to off-peak periods. Finally, it is also likely that some travellers may desist doing this particular trip.

It has been proven in some cities that up to 30% of motorized trips may diminish after a measure of reducing street capacity for cars. And this progressive decrease in the number of motorized trips in the city, and its substitution by other modes, it is precisely the objective of many urban mobility plans.

In short, the social value attributed to land today obtained for use by pedestrians, bicycles or public transport should be greater than or equal to the higher costs passed on to drivers of private vehicles, as long as traffic is not degraded below the level of service indicating increased congestion.

  • Sally Cairns, Carmen Hass-Klau and Phil Goodwin, (1998), “Evidence on the Effects of Road Capacity Reduction on Traffic Levels” London Transport.
  • Litman, T. (2011). “Valuing Transit Service Quality Improvements, Considering Comfort and Convenience In Transport Project Evaluation”, Victoria Transport Policy Institute.
  • Litman, T. (2015). “Transportation Cost and Benefit Analysis II – Air Pollution costs”, Victoria Transport Policy Institute.

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