As far as I understand (and supported e.g. by this):
- reckless driving: when one drives disrespecting traffic laws, yet not necessarily with the goal to cause harm
- aggressive driving: when one drives with the goal to cause harm or trouble
However, at least in the USA those definitions are state-dependant. In some definitions, such as from the Dept. of Transportation, they might overlap:
The first is "Reckless Driving" which is defined as "any person who drives any vehicle in a willful or wanton disregard for the safety of persons or property." Aggressing driving *should be less than reckless driving, but more than one simple act or failing to yield right of way. The Washington State law classifies aggressive driving under its "Negligent Diving in the Second Degree" (RCW 46.61.525), "operating a motor vehicle in a manner that is both negligent and endangers or is likely to endanger persons or property."