UN R171 — Supplement 2 to the 00 series of amendments

New paragraphs 2.31., 2.32. and 2.33. define the Hands On Request (HOR), the Eyes On Request (EOR) and the Direct Control Alert (DCA). A DCA must clearly and prominently instruct the driver to immediately resume at least the lateral control of the vehicle. Before, the instruction was to immediately resume either lateral, or lateral and longitudinal unassisted control. As a minimum, a DCA is considered confirmed when the driver has taken control without any continuous lateral assistance. In the condition for using head posture, “cannot be determined” becomes “can temporarily not be determined”. The manufacturer must now document and explain to the Type Approval Authority the functionality for multiple subsequent short aversions of eye gaze or head posture.

A driver braking input with a higher deceleration than the system induces must override and suspend longitudinal control assistance during the overriding period. The system must not resume this assistance without a separate driver action, but may provide it to avoid inappropriate distances to other road users. If the driver input reduces speed by not more than 30 km/h within 2 seconds, the system may resume assistance without a separate driver action. After resumption, the system may accelerate up to the current maximum speed; the rate of increase of acceleration must be gradual and controllable. Before, such a braking input overrode any feature associated with the longitudinal control, and assistance did not resume without a separate driver action. Technically reasonable tolerances may now be applied to the warning thresholds and the system’s designed speed range, in place of the operational limits.

The system may exceed the specified maximum lateral acceleration by up to 0.3 m/s2, but not above 3 m/s² (M1/N1) or 2.5 m/s² (M2/M3/N2/N3). For time periods of not more than 2 seconds, the system may exceed the specified maximum lateral acceleration by not more than 40 per cent. In that case, it must not exceed 3 m/s² (M1/N1) or 2.5 m/s² (M2/M3/N2/N3) by more than 0.3 m/s2. At the manufacturer’s request and with the Type Approval Authority’s agreement, alternative means may demonstrate the objectives when suitable test tracks are not available (4.2.5.1.1.1.3.). This requires at least one physical test at the overall declared maximum lateral acceleration for each of those paragraphs. In the tests, the production motorcycle option for the target is now of Category L3, “cyclist target” becomes “bicycle target”, and “motorists” or “motorist” becomes “motorcycle”.

Paragraph 5.3.7.2.2.2., which said that the system must not start the manoeuvre when a driver disengagement warning is currently being given, is deleted. In paragraph 5.3.7.2.3.3., the words “or a driver disengagement warning is currently being given” are deleted. Confirmation requests must at least use a specific signal (or combination of signals) in accordance with paragraph 5.5.4.1., in place of a specific visual signal. The system must now aim not to initiate the proposed manoeuvre, even if already confirmed by the driver, unless the listed conditions are met (5.3.7.2.3.5.). Item (a) now says that the target area, lane or path is determined by the system to be clear, in place of “is not obstructed”. In paragraph 5.3.7.2.3.7., “propose” becomes “initiate”, and “other traffic rules” becomes “performance requirements”.

The system must aim not to make an approaching vehicle in the target lane unreasonably decelerate, particularly where the lane change is not urgent (6.2.9.1.1.). Where making another vehicle in the target lane decelerate is necessary due to the traffic situation, the requirements of paragraph 6.2.4.1. apply. In paragraph 6.2.6., the system must generate a signal to activate the direction indicator “unless already activated by the driver”. The merging requirement in paragraph 6.1.2.1. now starts with the condition “If the system has the capability to assist in merging roads”. New item (d) reads: “Provide sufficient lateral distance to safely pass an object adjacent to the lane of travel (e.g., a cyclist in a cycle lane)”. Item (b) on passing a very slow-moving vehicle or road user no longer includes the words “in or near to the lane (such as a cyclist in a cycle lane)”.

In paragraphs 5.1.2., 5.1.3. and 5.5.3.4.1.5., the manufacturer’s “implement strategies” or “take effective measures” duty becomes “the system shall be designed to”. The system must now aim to avoid rapid system fluctuations between ‘stand-by’ and ‘active’ modes, in place of “The manufacturer shall implement strategies” (5.3.5.1.1.). Control actions resulting from cancelling manoeuvres are now named among those that must remain controllable for the driver (5.3.6.1.). On identifying an approaching system boundary of a feature in ‘active mode’, the system must inform the driver with sufficient lead time to respond appropriately. The definition of Dynamic Driving Task (DDT) no longer ends with “in on-road traffic” (2.30.). The words “only a driver is in charge and responsible for vehicle dynamic control” are removed; the text now says that DCAS assists the driver by carrying out operational and tactical functions.

If the manufacturer is to take remedial action addressing DCAS design, the Type Approval Authority must upload the information to DETA in English. Before, if remedial action was required, the Type Approval Authority had to communicate this information to all Type Approval Authorities. The manufacturer must now report at least once a year until the production is definitively discontinued according to paragraph 14. The information listed in the table can be shared in confidence with other Type Approval Authorities on request; the manufacturer must then be notified. New entries read “The system is / is not capable of performing Driver-initiated manoeuvres” and “The system is / is not capable of performing Driver-confirmed manoeuvres”. Paragraph 4.4.2., on an oval surrounding the letters “UI” followed by the Unique Identifier, is deleted.