When adaptive cruise is engaged, the system hesitates when lead vehicles slows at a slow rate (no brake lights observed on lead vehicle), requiring operator to apply brakes. When adaptive cruise control is engaged during highway driving, intermittently, medium slowing of lead vehicle (brakes applied) the vehicle does not react in time to avoid collision without active and heavy brake application (jerking driver and/or passenger) to avoid collision. Above 65 miles an hour the adaptive cruise control does not leave adequate distance between vehicle and lead vehicle. I first noticed this immediately upon first long distance drive. This is an ongoing problem. Happening frequently between July 4th and July 12. Since the July 12 the car has not been used frequently in situation where the cruise is used regularly. However during the few times on the highway between July 12 and now, the problem has reoccurred.

- Boca Raton, FL, USA