Advanced vehicle technology is becoming more and more common on new vehicles, but these systems don’t work well in all driving scenarios. The latest testing by AAA Automotive Engineers evaluated low-speed capable Active Driving Assistance (ADA) systems, also known as Traffic Jam Assistance. These systems control the vehicle’s speed, maintain a safe following distance from the vehicle in front, and keep the vehicle centered in the lane in low speed, congested traffic.

In short, Traffic Jam Assistance can be described as the use of a vehicle’s Adaptive Cruise Control (ACC) and Lane Centering Assistance (LCA) in congested, slow-moving driving situations.

The testing shows that these system had trouble every 9 minutes on average in heavy traffic.

The testing involved hands-on and hands-off systems on five different vehicles. Hands-on systems require the driver to keep their hands on the steering wheel while the ADA system is in use. Hands-off systems allow the driver to take their hands off of the steering wheel in most conditions while the ADA system is active, though in specific conditions the driver may be asked to place their hands back on the steering wheel.

“Testing by our AAA Automotive Engineers show that while ADA systems can help in certain driving situations, they never replace an engaged driver,” says Marie Dodds, public affairs director for AAA Oregon/Idaho. “While Traffic Jam Assistance is designed to work in congested traffic, these systems can have trouble every 9 minutes, which means that drivers need to always stay alert and be ready to take over control of the vehicle.”

Overall Results

In total, notable events were recorded every 3.2 miles, which is approximately every 9.1 minutes on average. A “notable” event was defined as any situation in which the ADA system failed to handle the driving conditions adequately, as determined by the researcher driving the vehicle.

The most common incidents reported were inadequate responses to cut ins, which required a researcher to intervene 90% of the time. Cut ins are defined as instances when a vehicle enters the lane directly in front of the test vehicle.
The second most frequent issue was inadequate Lane Centering Assistance. Lane Centering is a driver assistance system that uses cameras and other sensors to keep a vehicle centered within its lane, providing steering assistance to prevent drifting.

Engineers reported a difference between hands-on and hands-off ADA systems.

Hands-on systems require the driver to keep their hands on the steering wheel while the ADA system is in use. The ADA system utilizes sensors such as cameras and radar to monitor the driving environment (road condition, lane lines, etc.).

Hands-off systems allow the driver to remove their hands from the steering wheel in most situations but may require them to put their hands back on in certain conditions. These systems use similar sensors, but they also commonly rely on roads that are pre-mapped in the system.

The findings revealed that drivers of hands-on systems had to intervene due to driving events three times more frequently than those for hands-off systems.
Though hands-free most of the time, drivers using hands-off systems were asked to re-engage by placing their hands back on the wheel approximately once every 5.5 miles or every 15.3 minutes, requiring continuous driver engagement.

Test Vehicles

AAA chose to test new vehicles from the 2024 model year that all have significant sales in the U.S. and are from a mix of manufacturers:

2024 Ford F-150 Platinum SuperCrew 4WD (hands-off)
2024 Honda Accord LX Sedan (hands-on)
2024 Lexus RX 450h+ Luxury (hands-off)
2024 Mazda CX-30 2.5 Turbo Premium Plus (hands-on)
2024 Volkswagen Atlas SE AWD w/ Technology Package (hands-on)

Each test vehicle was instrumented with equipment that was used to continuously record data during testing.

Each vehicle was driven an average of 342 miles over a period of 16.2 hours, with GPS data, video, and audio continuously recorded to capture traffic conditions, vehicle behavior, and driver observations.

AAA Recommendations

Advanced vehicle technologies have the potential to reduce crashes and save lives. But AAA testing shows that none of these systems are foolproof. AAA recommends:

Remain in control and be prepared to intervene by braking or steering at all times while using ADA systems. Evaluated ADA systems are never a substitute for an engaged driver.
Eliminate distractions, including interacting with a smartphone. The need for the driver to intervene while using ADA systems can be frequent, especially in high traffic areas.
Maintain awareness, stay engaged, and remain in complete control of the vehicle at all times, regardless of the advanced driving assistance systems in use.
Be familiar with how their system operates. Read the vehicle owner’s manual to learn when, where, and how to use them.
Select a following distance that suits the driving situation to allow for more time to react to a situation and intervene when needed.

AAA shares its research and testing with industry leaders and automakers. Collaboration is key to enhance testing and expand consumer education about advanced driver assistance technologies as they become more widely available.

AAA encourages automakers to focus on:

Enhancing ADA performance, particularly focusing on improving cut-in response and lane-centering behavior.
Improving the visibility of alerts related to the deactivation of ADAS features to ensure drivers are aware when features are active or inactive.

AAA has also worked with other organizations, including Consumer Reports, J.D. Power, National Safety Council, PAVE, and SAE to develop the standardized naming conventions for ADAS (advanced driver assistance systems) technologies. Learn more at “Clearing the Confusion.”

Source: AAA

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