In this article, scientists explored ways to identify cost-effective strategies to reduce greenhouse gas emissions in the transport sector. They used a method called marginal abatement cost curves to show the relationship between reducing emissions and the costs involved. By analyzing the energy system in South Africa's Gauteng province, they found that while the transport sector wasn't the most cost-efficient area for emission reduction, there were still several affordable ways to cut down on emissions. The study demonstrates that by looking at different strategies, like improving fuel efficiency or using cleaner energy sources, we can make a significant impact on reducing greenhouse gas emissions without breaking the bank.