Tag Archives: urban

Activité Physique, Changement climatique/Climate change

Autonomous cars will negatively influence active travel patterns

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Drinking a craft beer on the terrace in Phoenix, I found an idea for this new blog article. I was surprised by the high number of driverless taxi in the town center. I cogitated about their potential negative impact on active travel patterns because I wrote an article here 3 years ago.

As researcher in physical activity sciences, I have my own ‘pro’ active transport bias. However, I found a very good paper examining this question with a systemic and evidence-based approach (1).

Authors examined the mechanisms by which active transport can be affected by autonomous vehicles (AV) in driverless cities (46 papers included). They also explained that AV are always presented as a cost-effective solution because their use may be associated with a drastic reduction car crashes and (maybe) congestion costs. However, the full (true) costs are rarely computed (environmental, health, cost).

What are the key points from their work ?

Autonomous vehicles

  • Private versus shared autonomous cars could have different determinants and consequences on active travel in urban context.
  • AV change the value of travel time. Indeed, you can sleep, work, be engaged in social activities during your trip. Thus, the active transport travel time could be perceived as wast time among walkers or bicycle users.
  • Conflicts or crashes between cyclists and normal cars or AV could increase because the behaviors of pedestrians or AV can be misinterpreted by human drivers. There also are some possible issues about human AV interactions.
  • AV could be associated with urban sprawl rebound effect. I other words, I can live further away from my office because I can work or sleep during the AV commuting trip.

Shared autonomous vehicles (e.g., taxi, small bus)

  • An analysis of shared Uber services in four US cities showed that traveled miles could double, and users switched from public or active transport modes.
  • The type of shared AV could have very different effects on AT patterns: door to door demand responsive, fixed line service, first or last mile

A very informative framework is provided in the article. Very helpful for stakeholders. Authors concluded that “urban planning must not be subordinated to accommodate AV”.

PS: here, maybe the worst example of autonomous car potential use

1. Shatu F, Kamruzzaman Md. Planning for active transport in driverless cities: A conceptual framework and research agenda. J Transp Health. 1 juin 2022;25:101364.

Activité physique/Physical activity, Changement climatique/Climate change, Santé/Health

Car free days and sustainable physical activity.

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A systematic review examined the health benefits associated with car free events and health outcomes (e.g., air pollution, physical activity, noise) (1). Among 23 included papers, one collected device-measured physical activity data (2), two estimated the physical activity levels of population with surveys (3,4).

Ciclovia is a weekly event created in Bogota, Colombia. Every Sunday, about 121 kilometers (70 miles) of roads are closed to motorized traffic. I can easily understand this impact with the following video.

The Ciclovia initiative was associated with a moderate and vigorous physical activity increase of 6 minutes and a sedentary behaviour reduction of 19 minutes among children participating (2). Most Ciclovia participants (adults) reported had low-to-middle educational attainment, and did not own cars. This event was associated with a possible 13% rate of people attaining international guidelines.

Another initiative was examined. Brownville, Texas, USA closes 3 miles (ca. 5 km) of town center streets (4 to 6 times per year). During this car-free event, 17.3% of attendees met weekly recommended physical activity levels.

This low number of included paper is surprising. Authors included papers or reports from grey literature but (maybe) they did not include the papers published in Spanish. Another explanation may be the lack of resources to measure physical activity behaviors (5). For instance, 17 countries of Latin America had a Ciclovia program between 1974 and 2016 (6). Only two articles (in English) was found on this initiative.

Two US studies (not included in this review) investigated the physical activity related behaviours during a Ciclovia program carried out in San Diego and Los Angeles, respectively.

Direct observations were performed in San Diego. It indicated that 85% of attendees were bicycling and 15% were walking. Study participants reported an average of 144 minutes of physical activity during the Ciclovia event. 39% of participated met the physical activity recommendations. Moreover, no significant differences were found between gender, ethnicity, income (7).

The Clovia program was named CicLAvia in Los Angeles (8). This initiative was initiated in 2010, and repeated 4 times per year for 6 miles (ca. 10 km). Physical activity data were collected with video cameras (at 1-mile intervals along the CicLAvia route), GPS “wore” by volunteers following the participants, and questionnaires. The GPS data showed an average traveling distance of 8.68 miles. At a speed of 6 miles/h, it would take 1.45 h to traverse this distance. Authors estimated that a total of 163,000 to 245,000 MET hours was expended by cyclists and a total of 13,500 to 18,000 MET hours was expended by pedestrians. 50% of respondents met the national guidelines of 150 min per week. Nearly 27% of participants said they if they had not been at CicLAvia, they would have stayed home while another 18% said they would have been sedentary.

In health and climate change perspective (9), these events may be a useful temporary solution to:

  • decrease the air/noise pollution exposition,
  • increase the physical activity level of local population,
  • offer a safe experimentation of active transport for all,
  • experiment a city with lower car traffic.
  • 1. Glazener A, Wylie J, van Waas W, Khreis H. The Impacts of Car-Free Days and Events on the Environment and Human Health. Curr Envir Health Rpt. 1 juin 2022;9(2):165‑82.
  • 2. Triana CA, Sarmiento OL, Bravo-Balado A, González SA, Bolívar MA, Lemoine P, et al. Active streets for children: The case of the Bogotá Ciclovía. PLOS ONE. 15 mai 2019;14(5):e0207791.
  • 3. Salazar-Collier CL, Reininger B, Gowen R, Rodriguez A, Wilkinson A. Evaluation of Event Physical Activity Engagement at an Open Streets Initiative Within a Texas-Mexico Border Town. J Phys Act Health. 1 août 2018;15(8):605‑12.
  • 4. Torres A, Sarmiento OL, Stauber C, Zarama R. The Ciclovia and Cicloruta programs: promising interventions to promote physical activity and social capital in Bogotá, Colombia. Am J Public Health. févr 2013;103(2):e23-30.
  • 5. O’Donovan G. Accuracy and inequalities in physical activity research. The Lancet Global Health. 1 févr 2019;7(2):e186.
  • 6. Sarmiento OL, Díaz del Castillo A, Triana CA, Acevedo MJ, Gonzalez SA, Pratt M. Reclaiming the streets for people: Insights from Ciclovías Recreativas in Latin America. Preventive Medicine. 1 oct 2017;103:S34‑40.
  • 7. Engelberg JK, Carlson JA, Black ML, Ryan S, Sallis JF. Ciclovía participation and impacts in San Diego, CA: The first CicloSDias. Preventive Medicine. déc 2014;69:S66‑73.
  • 8. Cohen D, Han B, Derose KP, Williamson S, Paley A, Batteate C. CicLAvia: Evaluation of participation, physical activity and cost of an open streets event in Los Angeles. Preventive Medicine. 1 sept 2016;90:26‑33.
  • 9. Bernard P, Chevance G, Kingsbury C, Baillot A, Romain AJ, Molinier V, et al. Climate Change, Physical Activity and Sport: A Systematic Review. Sports Med. 1 mai 2021;51(5):1041‑59.