PHV and taxis would be decisive for the efficient management of Low Emission Zones across Europe, according to a study carried out by researchers at the University of Barcelona
  • Researchers at the University of Barcelona have developed a study that analyzes the capacity of taxis and PHV to improve the implementation of low-emission zones in cities.
  • PHVs and taxis reduce congestion by 7% and CO2 emissions by 6%, so, among other reasons, they would help achieve the objectives of the LEZs, according to a study conducted by researchers at the University of Barcelona (UB) in collaboration with Cabify.

Madrid, September 14, 2023. A research group at the University of Barcelona (UB), in collaboration with the international multi-mobility platform Cabify, has analyzed the role that PHVs and taxis could play in implementing low-emission zones (LEZ). So far, LEZs have been implemented in 14 cities in Spain, while another 135 will have to implement them in the coming months.

The study reveals that, together with collective public transport, on-demand shared mobility services, including micro-mobility and personal mobility, can become great allies in the management of efficient mobility that aims to maximize the net benefits of implementing traffic restriction measures such as LEZs.

According to a report published by The Clean Cities Campaign1 between 2019 and 2022, the total number of active LEZs in Europe increased by 40%, from 228 to 320. By 2025, 507 LEZs will be in place in Europe (which means a +58% increase compared to June 2022), namely due to new national laws in France, Spain, and Poland that mandate or support the adoption of such schemes.

“PHVs and taxis can be a decisive factor in achieving the objectives of reducing pollutant emissions, so it is essential to address them as strategic actors in urban mobility and that local governments take into account their ability to contribute when regulating the LEZ”, says Marc Tarrés, a researcher at the University of Barcelona (UB) and co-author of the study.

In practice, the evidence shows that LEZs reduce pollution because they encourage vehicle fleet renewal. Still, they do not always reduce traffic levels or congestion either because the purchase of new vehicles allows circumventing the restriction or because of a traffic shift from the restricted to the unrestricted zone. Therefore, it is necessary to complement the ZBEs with other measures, such as improved collective public transport services. However, the necessary resources are not always available to achieve this objective.

The study confirms that on-demand mobility services (PHV and taxis) can become a better mobility alternative than collective public transport for some demand segments, complement collective public transport, achieve a more efficient match between supply and demand than collective public transport through digital platforms, promote a lower demand for privately owned vehicles and contribute to a better traffic composition.

Likewise, on-demand mobility services and digital platforms increase the efficiency of the chauffeur-driven transport vehicle sector by using less polluting vehicles, traveling a shorter empty distance between services, or having a system that discriminates between peak and off-peak hours.

PHV and taxis are also essential for the mobility of citizens who cannot drive, either due to disability, lack of license, age, or alcohol consumption, among other reasons.

“PHVs and taxis can compete with public transport when it is deficient or complement it, facilitate the ‘last mile’ and cover underutilized routes,” says Xavier Fageda, a researcher at the University of Barcelona (UB) and co-author of the study. In addition, they can reduce the purchase of private vehicles by up to 3%. PHV, taxis, car-sharing, and bike-sharing services reduce congestion and CO2 emissions, with a decrease of up to 7% in congestion and 6% in emissions, making them an efficient tool to implement LEZs.

This research, in collaboration with the Spanish multi-mobility platform Cabify, was commissioned by the Fundació Bosch i Gimpera (FBG) of the University of Barcelona (UB) to the Research Group on Governments and Markets (GiM) of the Faculty of Economics and Business of the UB, the Observatory of Analysis and Evaluation of Public Policies and the Research Group New Regulations in Urban Transport (NURETU) of the Faculty of Law of the UB.


About Nuretu

NURETU (New Regulations in Urban Transport) is a research group linked to the University of Barcelona (UB) but with researchers from different Spanish and foreign universities. Most of the members are lawyers, but engineers, economists and geographers also participate. Its objective is the multidisciplinary study of the regulatory challenges that arise in the field of urban mobility, taking into account the different operators, whether traditional or new. The results of its research are presented to the public through various dissemination activities in collaboration with the Chair of Public Services Regulation Law (CARSEP), recognized by the UB, as well as in other forums.

To achieve the transfer of their research results, NURETU researchers, in addition to publishing in recognized journals, collaborate in the drafting of reports as well as participate in the development of regulatory proposals.

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About Observatori d’analisii avaluació de politiques públiques

The Observatory of analysis and evaluation of public policies of the University of Barcelona (UB) is an Observatory of the UB, which pursues the objectives of promoting the culture of analysis and systematic evaluation of public policies, providing academic studies and rigorous tools to improve the evaluation of policies and the institutional context in which they are developed, and become a social reference for the discussion and debate of policies of particular relevance, as well as a reference forum for the generic debate of methodologies and strategies of analysis and evaluation of policies.

The observatory is composed of UB researchers, mainly from the Department of Econometrics, Statistics and Applied Economics (Public Policy Section), and external collaborators from various universities and international research centers. These researchers share research interests in the analysis and evaluation of public policies in different fields and cooperate in the achievement of the Observatory’s objectives. For more information, please visit the Observatory’s website:


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