Why commuter journeys hold a vital key to urban decarbonisation

In main­land France, com­mut­ing accounts for a sig­ni­fic­ant pro­por­tion of the car­bon foot­print. These jour­neys made by the work­ing pop­u­la­tion are under­taken by car or motor­bike and account for 75% of their travel, accord­ing to the latest nation­al mobil­ity sur­vey car­ried out in 2019¹. As a res­ult, these jour­neys alone account for 13 % of green­house gas (GHG) emis­sions from the trans­port sec­tor (equi­val­ent to 17.4 mil­lion tonnes of car­bon diox­ide, CO₂, in 2019) and there­fore rep­res­ent a key area for redu­cing emissions.

How­ever, the avail­able indic­at­ors do not show any pos­it­ive trend, high­light­ing the import­ance of redu­cing these emis­sions. Between 1982 and 2019, the aver­age dis­tance of com­mutes almost tripled, rising from 5 km in 1982 to 14 km in 2019². Fur­ther­more, the num­ber of work­ers liv­ing and work­ing in main­land France whose place of employ­ment is loc­ated out­side their res­id­en­tial catch­ment area³ increased by 50 % between 1999 and 2018⁴. These 3 mil­lion work­ers live more than 25 km from their place of employ­ment. “These sig­ni­fic­ant dis­tances are covered by car in 90% of cases. Yet these jour­neys are still largely over­looked in dis­cus­sions on redu­cing trans­port-related GHG emis­sions,” note the authors of an Atlas on com­mut­ing pub­lished in 2024.

The Atlas provides a detailed account of these com­mutes, but behind the fig­ures lie sig­ni­fic­ant region­al dis­par­it­ies. “As com­mut­ing dis­tances have increased, we wanted to char­ac­ter­ise travel pat­terns in great­er detail, focus­ing in par­tic­u­lar on those work­ers who com­mute out­side their res­id­en­tial catch­ment area,” explains Ben­oit Conti, co-author of the Atlas. “How­ever, we found that travel pat­terns vary greatly; there is no easy or single solu­tion for redu­cing car use on these journeys.”

To increase the share of pub­lic trans­port, it may be worth­while to adjust rail ser­vices where a rail line exists, or to devel­op bus ser­vices or carsharing.

In some regions, traffic flows are highly con­cen­trated along cer­tain routes. This is par­tic­u­larly the case between cer­tain cent­ral towns, such as Belfort and Mont­béliard, or along the Tours–Blois–Orléans cor­ridor. Oth­er regions see traffic con­cen­trated with­in spe­cif­ic cor­ridors, such as along the Medi­ter­ranean coast or the Rhône cor­ridor. These con­fig­ur­a­tions are ideal for devel­op­ing and pro­mot­ing the use of pub­lic trans­port. “To increase the share of pub­lic trans­port, it may be worth­while to adjust rail ser­vices where a rail line exists, or to devel­op bus ser­vices or car­shar­ing,” points out Ben­oit Conti.

Anoth­er approach to man­aging these massive traffic flows is to pro­mote inter­mod­al­ity, i.e. the com­bin­a­tion of sev­er­al modes of trans­port for a single jour­ney. This solu­tion is par­tic­u­larly bene­fi­cial for towns and cit­ies with metro, tram or rail ser­vices, and for long jour­neys (25 to 50 km). In a scen­ario based on the imple­ment­a­tion of meas­ures to pro­mote inter­mod­al­ity (through pri­cing policies and improved access to sta­tions), CO₂ emis­sions could be reduced by around 40%⁵.

Added to this are express cycle net­works, cyc­ling infra­struc­ture designed to encour­age wide­spread cyc­ling over medi­um and even long dis­tances. “These net­works con­nect a densely pop­u­lated area with its out­skirts and even the sur­round­ing rur­al areas, thanks to safe, high-qual­ity infra­struc­ture,” explains Man­on Eskenazi. Con­ceived in the Neth­er­lands in the 1970s, these schemes gradu­ally became a pri­or­ity for French cit­ies in the 2010s. Of the 30 largest French urb­an areas by pop­u­la­tion, 15 have a cycle express net­work pro­ject. None of them yet has a fully imple­men­ted net­work. Accord­ing to a recent study⁶, nearly four in five jobs are with­in a three-minute cycle ride of exist­ing schemes, rep­res­ent­ing 7 mil­lion jobs. The study estim­ates that, on aver­age, 22% of motor­ists could switch to cyc­ling thanks to these net­works (ran­ging from 13% in Cler­mont-Fer­rand to 38% in Tours).

“One of the main con­straints on express cycle net­works out­side densely pop­u­lated areas is land use; it is there­fore import­ant to pri­or­it­ise improv­ing the coex­ist­ence of motor­ised vehicles and bicycles,” points out Mari­ane Thébert. “This involves redu­cing the speed of motor traffic, using rur­al lanes for cyc­lists, widen­ing exist­ing county roads to cre­ate ded­ic­ated lanes for soft mobil­ity, and so on.”

But these solu­tions are not always effect­ive. “By focus­ing on those work­ers who com­mute out­side their res­id­en­tial catch­ment areas, we have found that prac­tices vary widely and that there is no easy or single solu­tion for redu­cing car use on these jour­neys”, emphas­ises Ben­oit Conti. Pub­lic trans­port, inter­mod­al trans­port and express cycle net­works are of lim­ited effect­ive­ness in regions where, con­versely, work­ers’ jour­neys are scattered and dis­persed. In Brit­tany and Nor­mandy, for example, there are many jobs in rur­al areas and it would be too costly and com­plex to devel­op a pub­lic trans­port ser­vice. “The envir­on­ment­al prob­lem posed by cars is not merely a trans­port issue, and pur­su­ing a policy centred on trans­port pro­vi­sion will not be enough,” points out Ben­oit Conti. “It also requires spa­tial plan­ning policies relat­ing to hous­ing, employ­ment, access to pub­lic ser­vices, and so on.” Thus, com­bat­ing urb­an sprawl, increas­ing the dens­ity of built-up areas, revital­ising town centres and facil­it­at­ing access to hous­ing near employ­ment hubs are all meas­ures that effect­ively tackle CO₂ emis­sions and air pol­lu­tion by redu­cing road traffic.

This coordin­ated approach, involving trans­port, town plan­ning and the organ­isa­tion of work, com­plic­ates the imple­ment­a­tion of solu­tions. “The more we con­sider long-dis­tance jour­neys, the more we cross dif­fer­ent areas of jur­is­dic­tion, and the more action needs to be coordin­ated… We’re always look­ing for a magic solu­tion!” says Mari­ane Thébert. Enacted in 2019, the Mobil­ity Frame­work Act (loi d’ori­ent­a­tion des mobil­ités, or LOM) is spe­cific­ally designed to roll out pub­lic action across the whole coun­try and to strengthen coordin­a­tion at vari­ous admin­is­trat­ive levels. How­ever, ini­tial ana­lyses sug­gest the sys­tem is not very effect­ive: admin­is­trat­ive delays, a lack of fin­an­cial resources, incon­sist­en­cies between jur­is­dic­tions and insti­tu­tion­al rival­ries are ham­per­ing pro­gress⁷.

By redu­cing the role of the car in com­mut­ing, sys­tem­at­ic meas­ures offer not only envir­on­ment­al and cli­mate bene­fits, but also social ones.

By redu­cing the role of the car in com­mut­ing, sys­tem­at­ic meas­ures offer not only envir­on­ment­al and cli­mate bene­fits, but also social ones. Cer­tain pop­u­la­tion groups are more exposed to the nuis­ances and con­straints asso­ci­ated with com­mut­ing, and manu­al work­ers rep­res­ent a group that con­trib­utes par­tic­u­larly high levels of emis­sions due to the hous­ing and employ­ment con­straints they face⁸. “The social issue is far too often over­looked, but it lies at the heart of mobil­ity chal­lenges, and it is cru­cial to take it into account in the mobil­ity trans­ition,” con­cludes Ben­oit Conti.

Interview by Anaïs Maréchal