The Insurance Institute for Highway Safety (IIHS) recently announced their ACC and lane keeping tests on five high-end cars including Tesla and Mercedes-Benz. After testing, it was found that driving assistance is prone to fail in many situations.
Recently, the Insurance Institute for Highway Safety (IIHS) released a test report on the ACC and lane keeping of five models of Tesla (Model3 and S), Mercedes-Benz E Series, BMW 5 Series and Volvo S9. The results found these The system can play the role of assisting the driver, but in many cases the system may fail. For example, braking is too cautious when seeing the shadow; for example, the sensor cannot detect the lane line and turns to the shoulder. The evaluation of adaptive cruise control and active lane keeping shows variable performance in some typical driving situations, such as vehicles approaching a stop and driving on hills and curves. These results prove that today's systems are not a strong substitute for human drivers.
The 2017 BMW 5 series are equipped with "Driving Assistant Plus", the 2017 Mercedes-Benz E-class models are equipped with "Drive Pilot", and the 2018 Tesla Model 3 and 2016 S-models are equipped with "autopilot" (software version 8.1 respectively). And 7.1) and 2018 Volvo evaluated the S90 with "advanced assistance". All five models have IIHS's superior automatic emergency braking system. In the range of SAE International's 0 to 5 fully automated driving, the combination of ACC and active lane keeping belongs to level 2. They can assist in steering, speed control and following distance, but the human driver is still responsible and must keep driving.
To summarize their performance:
1. Drive to a stationary vehicle at a speed of 50km/h per hour, turn off the ACC and test the automatic brake open state. Only the Tesla Model 3 and Model S failed and collided with the stationary target. 2. Carry out the same test above with the ACC turned on, and all vehicles have passed this part. 3. The test car followed a pilot car that decelerated first and then accelerated. Each car performed well in this test and can drive safely. 4. The test vehicle follows a pilot vehicle that changes lanes, and a stationary vehicle is found in the path of the test vehicle. The test vehicle had a reaction time of approximately 4.3 seconds before colliding with a stationary vehicle. Similarly, all the test vehicles performed well, and none of them crashed into a stationary vehicle.
Let's take a look at it in detail below:
Adaptive cruise control
Engineers evaluated the ACC system in four different series of track tests to understand how they deal with stopped guided vehicles and guided vehicles to leave the lane, and how the system accelerates and decelerates in four test environments.
In this series of tests, the vehicle is driving towards a stationary vehicle target at a speed of 31 mph, ACC is turned off and automatic braking is turned on to evaluate the automatic braking performance. In this test, only two Teslas hit a stationary target.
Repeat the same test with the ACC turned on, and set the short, middle and long distances in multiple runs. With ACC activated, the 5 series, E class, 3 and S brakes brake earlier than emergency braking and still avoid the target. It brakes in the same way regardless of the distance setting. Tesla braked earlier than the 5 Series and E-Class before the impact.
Compared with other models with ACC performance, the S90 brakes more suddenly than other automatic braking performance. In the ACC test, the S90 brakes with a force of 1.1g and uses it only 1.1 seconds before impact to avoid a collision.
The third situation involves following the vehicle in front to decelerate to a stop and then accelerate. In this test, each ACC system can decelerate smoothly.
The fourth scenario involves the test vehicle following the lead vehicle, which changes lanes at a collision time of approximately 4.3 seconds, and has a stationary inflatable target vehicle in the forward path.
No vehicle hits the target. The 5 series, E-Class and Tesla brake earlier than the S90, and are gentler, similar to the active ACC test.
Tracking tests are suitable for evaluating functions and performance in a controlled environment. Under ideal conditions, advanced driver assistance systems can perform better in more complex driving situations. A typical example is the ACC test of a stopped vehicle. On the track, 5 series, E-class and Tesla brakes to avoid the target vehicle. The owner's manual of all test vehicles warned that ACC may not be able to brake when it encounters a vehicle that has entered the sensor range and has stopped. in this way.
On the road, the engineer noticed that every vehicle except Model 3 failed to respond to the vehicle stopped in front. Unnecessary or overly cautious braking is a problem that IIHS noticed in Model 3. Within 180 miles, the car unexpectedly decelerated 12 times, 7 of which coincided with the shadow of a tree on the road, and the other times were when facing an oncoming vehicle in another lane or a vehicle crossing the road ahead.
"The braking incidents we observed did not cause unsafe conditions because the deceleration was light and short enough so that the vehicle did not decelerate too much. However, unnecessary braking may pose a risk of collision during heavy traffic, especially if It is too responsive," said Jermakian, an IIHS engineer.
“In addition, drivers who feel that their car’s braking is unstable may choose not to use adaptive cruise control and will miss any safety benefits of the system.â€
The potential safety benefits of ACC are promising. This technology is usually bundled with forward collision warning and automatic braking. Research by IIHS and HLDI has found that these systems together will have the benefit of reducing collisions. A study funded by the federal government found that drivers who use ACC have a longer and safer tracking distance than drivers who do not. Nevertheless, the IIHS test showed that the current ACC system is not yet ready to handle speed control in all traffic situations.
Lane keeping
Curves and hills are a challenge for the lane keeping system. All five systems provide steering assistance to center the vehicle in a clearly marked lane. They can also use the leading vehicle as a guide when driving at low speeds or when the leading vehicle blocks the lane markings ahead.
To test active lane keeping on the curve, engineers conducted six tests on each vehicle on three different road sections, with a radius ranging from 1,300 to 2,000 feet.
In all 18 trials, only Model 3 remained in the lane. Model S was very close to 3 but was over-corrected on a curve, causing it to cross the line on the inner side of the curve in one trial. None of the other systems tested provided enough steering input to stay in their lane at all times, often requiring the driver to provide additional steering to successfully navigate the curve.
The Mercedes-Benz E series stayed in the lane 9 times in 17 runs, and misrecognized the lane markings in 5 tests. The system broke away on its own in an experiment and crossed two lines. The 5 series remained in the lane in 3 of the 16 trials and was more likely to disengage rather than be guided out of the lane. S90 stayed on the lane in 9 of the 17 runs and crossed the lane line in 8 runs.
When trying new cars in the hilly area of ​​Virginia, engineers noticed early on that advanced driver assistance systems, which rely on seeing road markings to keep the vehicle in the lane, are sometimes overwhelmed by hills. When the vehicle climbs to the hillside, the lane markings on the road become blurred.
For the road test, the engineer drew a route of hills with three different slopes. The driver conducted six test runs on each mountain of each vehicle.
The E series stayed in its lane in 15 of the 18 trials and stayed on-line in one trial. When the lane line was not visible, it continuously provided steering support without unstable movement. Model 3 stayed in the lane for everything except one test.
In contrast, the 5 series, S-type and S90 are very passive. The 5 series turned or crossed the lane line for a period of time, requiring the driver to get it back on track. Sometimes the car will disengage the steering assist on its own. In all 14 valid trials, the car failed to stay in the lane.
Model S made a lot of errors in the mountain test. In 18 trials, only 5 of them stayed in the lane. When on the top of the mountain, the Model S turned left and right until the correct position in the lane was determined. Test drivers were shocked because it rarely warned them to take over when looking for the lane, and the car would often turn to the adjacent lane or shoulder.
When the driver intervenes to avoid potential trouble, the active lane keeping system disengages. After the driver re-uses the autopilot, the steering assistance is restored.
One problem that drivers noticed in some vehicles is that even if the driver intends to keep going, he will tend to follow the leading vehicle into the exit lane in slow-moving traffic. When the car is too slow to track the lane line, the active lane keeping system will use the vehicle in front as a guide. If the towing vehicle exits, the trailing vehicle may also exit.
The evidence of the safety benefits of active lane keeping systems is not as obvious as ACC. Nevertheless, the potential for preventing collapse and saving lives remains great. IIHS research shows that, under normal circumstances, preventing lane departure accidents in a year can save nearly 8,000 lives. The Lane Departure Warning system is associated with a 11% reduction in the collision rate of bicycles of all severity, side rubbing and frontal collision, and a 21% reduction in the collision rate of the same type of injury.
IIHS is developing ratings for driver assistance systems. Road and track tests are helping IIHS develop consumer rating plans for advanced driver assistance systems. At the same time, they will make recommendations on regulations for fully autonomous vehicles.
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