An innovative solution for a smaller environmental footprint.

At WEBREATHE, we believe the future of mobility depends on a sustainable approach. Our 2FLOW solution, dedicated to counting and making the most of passenger flows, gives public transport networks the data they need to understand travel patterns, adjust their service and, in turn, reduce their environmental footprint.

We put passengers and crowding levels back at the heart of the decisions made by operators and transport authorities. By making it easier to match supply with demand, 2FLOW brings passengers greater comfort, renews their desire to use public transport and reduces the use of private cars. The goal is simple: make public transport more attractive so that it is used more and, as a result, the car is used less.

Greenhouse gases, foremost among them carbon dioxide (CO₂), together with nitrogen oxides (NOₓ) and fine particles (PM), have a significant impact on the climate, the environment and human health. CO₂ contributes to global warming; nitrogen oxides degrade air quality and cause acid rain; fine particles penetrate the respiratory tract and affect cardiovascular health. According to the World Health Organization, air pollution is the leading environmental risk to health worldwide.

The name WEBREATHE, “we breathe”, sums up our mission on three levels. On board: vehicles sized to actual ridership, less crowded and more comfortable. In the city: every passenger who leaves their car behind means less CO₂, NOₓ and fine particles in the air we breathe. In the wallet: heavily subsidised, public transport costs far less than the car, so passengers can also breathe easier at the end of the month.

2FLOW is a complete, turnkey, customisable and scalable solution designed for public transport. It does more than count passengers: it makes use of the data collected to provide a comprehensive, reliable view of ridership, taking into account the integration, communication and data quality constraints specific to the sector. It is built on eight complementary building blocks.

With 2FLOW, operators have a technology that can adapt service to ridership. By analysing the data, they adjust timetables, routes, the number of vehicles in service and their size to offer a consistently optimised service. The result: smoother, more environmentally responsible operations that reconcile performance and sustainability.

• Fewer empty and under-used trips. The data make it possible to adjust lines and timetables to actual needs: extra services on the busiest trips, reduced frequencies on less-used lines. Fewer unnecessary trips mean less fuel burnt, and therefore less CO₂, NOₓ and fine particles.
• Better energy efficiency per passenger. By optimising the use of vehicles (buses, trams, trains) during demand peaks, 2FLOW improves energy performance per person carried and reduces the carbon footprint of every trip.

2FLOW collects and analyses ridership data in fine detail. This analysis reveals the times and places where demand is highest, particularly on bus rapid transit lines (BRT), and paves the way for optimised resource management.

• Less under-loading in off-peak hours. Operators adjust the number of vehicles in service while maintaining service quality, and cut fuel consumption and emissions during quiet hours.
• The right resources at peak times. 2FLOW provides the indicators needed to deploy exactly the number of buses required, no more and no less: smart management that maximises operational efficiency and minimises emissions per trip.

Thanks to historical data, operators anticipate future needs and optimise their fleet proactively. Tailored planning based on seasonal trends and events: by analysing past data, 2FLOW helps anticipate the impact of seasons or specific events, so that services can be adjusted and both over-use and under-use of vehicles avoided.

Our API-IV (Passenger Information) easily integrates essential data into existing applications: vehicle occupancy rates and real-time location, so that passengers can optimise their journeys and operators gain even greater visibility over their flows.

All in all, our customers benefit from far more than a counting tool: better planning, a better-used fleet and fewer unnecessary trips mean an improved passenger experience and lower CO₂, NOₓ and fine particle emissions, for a service that is both greener and more cost-effective.

The equivalence between a bus and cars depends on the bus’s capacity, its actual occupancy and the average number of people per car. A standard bus can carry 50 to 60 passengers: at full load, it therefore replaces 10 to 12 fully occupied five-seat cars. In reality, vehicles rarely run full. ADEME uses two reference values:

• 1.43 people per car for short-distance trips (under 100 km), the average occupancy of a five-seat car in 2022;
• 10 passengers per urban bus, the average occupancy rate used in the Base Carbone.

To compare the CO₂ emissions of different types of buses and cars, we use the well-to-wheel emission factors from ADEME’s Base Carbone, taking the “short-distance” values representative of urban trips. A bus emits more than a car per kilometre; it is the number of people carried that makes all the difference.

To carry 10 people over 100 km, a combustion bus emits 92 kg of CO₂, whereas the 7 cars it replaces emit around 145 kg (petrol car), more than a third less. An electric bus emits only 21.7 kg, 85% less than the cars. Per person, the bus remains markedly more frugal than a combustion-engine car, even at the average occupancy of 10 passengers; and every additional passenger lowers the footprint of all the others.

The same comparison can be made for local pollutants. Exact values depend on the age of the vehicles and their Euro standard; we use the averages published by ADEME to obtain a consistent estimate.

Key takeaways

• Electric bus: no direct NOₓ or particle emissions, and the lowest CO₂ per person of all road modes (2.2 kg per 100 km, i.e. 0.022 kg per kilometre).
• CNG bus: nearly three times less NOₓ and four times fewer particles than a diesel bus, for slightly higher CO₂ per person (10.4 versus 9.2 kg per 100 km).
• Combustion bus: 9.2 kg of CO₂ per person per 100 km, a third less than a diesel car (13.6 kg). At the average occupancy of 10 passengers, however, its NOₓ per person remain higher than those of a petrol car: hence the importance of occupancy and fleet renewal.
• Cars: petrol, CNG and LPG emit comparable CO₂ per person (14 to 14.5 kg per 100 km); the diesel car emits slightly less CO₂ (13.6 kg) but four to five times more NOₓ; LPG shows the lowest NOₓ of all cars and no particles.

These data clearly show the effect of vehicle type on emissions: electric buses and, to a lesser extent, CNG buses are the most effective at reducing pollutants per person carried. In every case, the fuller a bus is, the clearer its advantage over the car.

The four case studies that follow apply one and the same deliberately cautious method to ridership measured by 2FLOW. It answers two questions: what did the additional passengers avoid by leaving their cars behind, and how do fleet emissions per passenger change?

Sixteen electric buses fitted with 2FLOW counting cells on a bus rapid transit line. We compare ridership in 2021, before the equipment was installed, with that of 2022 and 2023.

Ridership rose by +25.6% in 2022 (+1,021,307 trips) and then by +3.8% in 2023 (+190,512 trips), making 1,211,819 additional trips in two years. The crowding data justified increasing the number of vehicles in service at key times from 10 to 16, which made this growth possible.

Between 2021 and 2023, each bus trip generated 32% less CO₂ per passenger: fleet emissions were spread over more passengers, and the distance per bus was reduced in 2023 thanks to a better match between supply and demand, with no loss of ridership.

Without the solution, 824,764 of these trips would have been made by car, equivalent to around 576,758 vehicle trips avoided (at 1.43 people per car). On this line, the use of electric buses and the optimisation of service using 2FLOW data thus avoided the production of 1.5 t of NOₓ, 11.3 kg of fine particles and 511.6 t of CO₂ in two years. These results illustrate the effect of investing in clean public transport sized to actual ridership.

In 2021, we fitted 12 combustion buses with counting cells and supplied the data to the operator via 2FLOW. The network was then strengthened step by step, with 6 additional buses between November 2021 and January 2023.

Ridership more than tripled in two years: +407,057 trips in 2022 and +66,597 in 2023, making 473,654 additional trips.

Between 2021 and 2023, emissions per passenger fell by 70.1%, thanks to ridership growth made possible by continuous optimisation of the network based on counting data and by the addition of CNG buses, which emit less NOₓ and fewer particles. Each trip emits three times less than in 2021.

Without the solution, 317,111 of these trips would have been made by car, equivalent to around 221,756 vehicle trips avoided. Under the cautious assumption, the network avoided 16.9 t of CO₂.

On Network B, the efforts to make the network more efficient and more environmentally friendly avoided hundreds of thousands of car trips, with a marked reduction in emissions per passenger. These tangible results illustrate the effect of investing in cleaner, more efficient and more sustainable public transport.

Forty-six combustion buses fitted with counting cells, whose data are made available via 2FLOW. With a constant fleet and distance travelled, ridership increased 2.3-fold in one year.

Ridership rose by +2,573,411 trips in 2023, i.e. +130%, with no increase in the number of buses or the distances covered.

Between 2022 and 2023, NOₓ, fine particle and CO₂ emissions per passenger fell by 57%. The number of passengers rose sharply while total bus emissions remained constant: the environmental impact of each trip is diluted accordingly.

With more than 2.5 million additional trips in 2023, 1,781,058 of which would have been made by car, the network avoided around 1,245,495 vehicle trips and, under the cautious assumption, 146.0 t of CO₂.

This project shows that public transport service better matched to demand can have a positive environmental effect by reducing pollution from individual travel, even before any investment in new vehicles.

Two hundred and twenty-seven vehicles fitted with counting cells, 137 CNG buses and 86 electric trams, on a network that has become free for its residents. We compare the measured 2023/2024 season with the projection for the 2024/2025 season.

The projection assumes +21,932,676 passengers (+20.5%) over the 2024/2025 season, split between the tram (92.7%) and buses (7.3%) according to observed ridership. The network’s trams have 263 places and an average occupancy rate of 77%, i.e. 202 people per tram.

* Projection made in September 2024; to be updated with the season’s actual counts.

The expected rise in ridership, partly due to the network becoming free, represents 14,447,054 trips that would have been made by car, equivalent to around 10,102,835 vehicle trips avoided over one season. With 93% carried by tram, these trips would avoid 10,065.8 t of CO₂, 25.4 t of NOₓ and 179.2 kg of fine particles.

With a constant fleet, the expected rise in CNG bus ridership would cut emissions per passenger by 17%. This project shows that improving public transport service, here by making it free, can have a major effect on pollution from individual travel, and that counting data make it possible to measure it.

2FLOW stands out as a key tool for greener, better-optimised mobility. By enabling smart management of passenger flows, the solution reduces unnecessary trips, optimises network resources and makes public transport more attractive.

The results observed on these four networks demonstrate the ability of counting data to support reductions in CO₂, NOₓ and fine particle emissions, while increasing ridership and avoiding millions of car trips. Across these four networks, the additional passengers represent, under our cautious assumptions, more than 10,740 tonnes of CO₂ avoided.

Applying the same method to all equipped networks, we estimate that we helped our customers avoid more than 15,000 tonnes of CO₂ in 2023, compared with 13,900 tonnes in 2022: a positive, ongoing trend that illustrates the growing effectiveness of our initiatives for air quality and against global warming.

Adopting solutions such as 2FLOW is essential to support sustainable mobility and improve air quality in cities: every passenger who leaves their car behind means more clean air for everyone.