Drivers who participated in an Insurance Institute of Highway Safety (IIHS) study said they are somewhat cautious about adaptive cruise control and active lane keeping features and prefer systems they believe make smooth, gradual movements.

Overall, drivers in the study said they would be reluctant to use the features in challenging driving conditions such as stop-and-go traffic and on local roads, but were comfortable using them in light traffic and on interstates.

The findings came in an IIHS analysis of 51 co-workers test drives to assess drivers reactions to these two semi-autonomous vehicle features.

The IIHS and HLDI employees who participated in the study drove one of five vehicles —  a 2017 Audi A4, 2017 Audi Q7, 2016 Honda Civic, 2016 Infiniti QX60 and 2016 Toyota Prius — equipped with adaptive cruise control. With the feature, the vehicle maintains a set speed and a set following distance from the vehicle in front of it. Three of the vehicles — the two Audis and the Civic — were also equiped with active lane keeping, which provides sustained steering input to keep the vehicle within its lane.

The drivers used the vehicles — with the technology continually activated — for periods ranging from one day to three weeks.

While the drivers viewed adaptive cruise control and active lane keeping somewhat positively overall — the kind of systems installed in the vehicles made a difference in their perceptions of the technology.

For example, drivers of the Audi A4 and Q7 viewed the adaptive cruise control more positively than the active lane keeping feature. The reverse was true for the Honda Civic where the active lane keeping earned higher accolades than the adaptive cruise control.

In addition, the drivers favored active lane keeping that they believed made infrequent steering corrections. They also preferred adaptive cruise control systems that they felt made smooth, gradual changes and consistently detected moving vehicles ahead.