Parents who drive their kids to school shouldn't be made to feel bad about causing climate change, a report says.
The study by the Campaign for Better Transport looks at ways the government could cut pollution levels from different types of transport.
It says the school run makes up a small amount of the UK's carbon emissions.
The report says concentrating on things like making companies use trains instead of lorries would be more helpful to the environment.
By bringing in new measures, Britain's carbon emissions could be cut by a quarter by 2020, the report says.
Carbon dioxide is one of the so-called greenhouse gases, which are thought to be warming up our planet.
The man who wrote the report, Keith Buchan, says although the school run isn't a huge factor in causing climate change, kids should still be encouraged to walk or cycle to school.
Mr Buchan says walking or cycling is better for kids' health, and helps cut the number of cars on the roads.