How Carpooling Cuts Carbon Emissions
Burning one litre of petrol makes about 2.35 kg of carbon dioxide. See, with simple sums, how much less your trips make when you share the car.
By YauzaiSafar Team Published 3 min read
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Every time a car burns petrol, it puts carbon dioxide (CO₂) into the air. CO₂ is the main gas that is warming our planet. Cars also give off smoke and other gases that make the air harder to breathe in busy cities.
Carpooling does not make a car trip clean. The car still burns fuel. But when four people share one car instead of driving four cars, a lot less fuel is burned in total. This article shows how much less, with simple sums.
How much CO₂ does a litre of petrol make?
Burning one litre of petrol makes about 2.35 kg of CO₂. This figure comes from the US Environmental Protection Agency (EPA), which says one US gallon of petrol (about 3.8 litres) makes 8,887 grams of CO₂.
You might wonder how one litre of petrol, which weighs less than one kilogram, can make more than two kilograms of gas. The answer is that most of the weight comes from the air. When petrol burns, the carbon in it joins with oxygen from the air to make CO₂. That oxygen adds the extra weight.
So the sum is simple:
CO₂ from a trip = litres of petrol burned × 2.35 kg
Example: one trip from Islamabad to Peshawar
The trip is about 185 km. A car that does 12 km per litre burns about 15.4 litres of petrol. That makes about 36 kg of CO₂.
Now think of four people making this trip on the same day.
| How they travel | Cars on the road | Total CO₂ |
|---|---|---|
| Each drives their own car | 4 | 145 kg |
| All four share one car | 1 | 36 kg |
By sharing one car, the four of them cut the CO₂ from their trip by about three quarters. Each person’s share of the pollution is a quarter of what it would be if they drove alone. (A full car uses slightly more fuel than an empty one, so the real saving is a little less, but still very large.)
Example: a daily drive to work
Small trips add up too. Say you drive 30 km to work and back every day, five days a week. In a month of about 22 working days, that is 660 km.
| How you get to work | Your CO₂ in a month |
|---|---|
| Driving alone | 129 kg |
| Sharing with one colleague | about half of that |
| Sharing with two colleagues | about a third of that |
Sharing also saves money on petrol. We work out the rupees in carpooling to work.
Fewer cars, less traffic
Carpooling helps in another way too. Every car that stays at home is one less car in the traffic jam.
Cars stuck in slow, stop-start traffic burn fuel without going anywhere. When there are fewer cars, traffic moves better, and the cars that are on the road waste less fuel and give off less smoke.
Other easy ways to burn less fuel
Whether you carpool or not, these habits lower your fuel use, and your petrol bill:
- Drive smoothly. Hard braking and fast starts waste fuel.
- Keep to a steady speed on the motorway instead of speeding up and slowing down.
- Check your tyre pressure. Soft tyres make the engine work harder.
- Don’t leave the engine running while you wait.
- Plan your errands so you do them in one trip, not three.
- Take out heavy things you don’t need from the boot.
The bottom line
Carpooling is one of the simplest things you can do to cut pollution from travel. You don’t need a new car. You just need to fill the empty seats in a car that is going anyway.
To work out the fuel your own trips use, see how to work out the fuel cost of a road trip. If carpooling is new to you, start with carpooling in Pakistan: a simple guide.
Sources
- Greenhouse Gas Emissions from a Typical Passenger Vehicle (opens in a new tab) , US Environmental Protection Agency
