articleThe Brief A new study finds that American drivers could save tens of millions of dollars every year by minding the speed limit. Additionally, by not speeding, drivers could cut carbon dioxide emissions by 57,000 metric tonnes every day, the paper stated. A lead foot takes an extra toll on the pocketbook without saving much time, a new study finds. In it, researchers show that the costs of going over the posted speed limits do not appear to outweigh the time saved by speeding. Why you should care:Researchers explained their study shows the simple step that drivers can take to save a little at the pump: obey the posted speed limit.