NHTSA is developing driverless car safety standards and it has questions – InformTFB

NHTSA is developing driverless car safety standards and it has questions

NHTSA is developing driverless car safety standards and it has questions


Note: the National highway traffic safety administration (NHTSA) and the Department of transportation issued a preliminary notice in November last year on a project to standardize driverless vehicle traffic safety. We asked Egil Juliussen, an experienced automotive industry analyst and EE Times columnist, to tell us about it. In this text, he will explain to us how NHTSA defines driverless cars, what is included in the “safety standards” and what questions the Agency raises for the industry to improve its bill.

On November 19, 2020, NHTSA published a preliminary version of its draft law with safety standards for unmanned vehicles. Comments and amendments to this document are accepted until February 1, 2021. Work on this document marks the beginning of standardization of the rules of operation of unmanned vehicles. The recommendations in this document may become one of the most important for the automotive industry for many years to come. What is NHTSA aiming for and what can we expect from this project?

The name of the bill sounds like “safety Basics for ride automation systems”. The official version of the document with a volume of more than 60 pages was included in the Federal register on December 3, 2020 (18-page section in small print). There is also a link where you can read public comments, and you can leave your own here.

To describe the hardware and software of unmanned vehicles, the Department uses the term “Automated Driving System (ADS)” (driving automation system – approx. an interpreter). I will also stick to this term later in the text.

Summary of the document

The following paragraph is a summary of the ADS bill.

The national highway traffic safety administration collects comments on the document with safety concepts for ride automation systems (ADS). This document will objectively define, evaluate, and Refine ADS security standards, and one of the document’s priorities is flexibility in making edits and updates. The Department strives to use the existing results and tools for the formation of this draft law, as work on the development of modern ADS continues. The Department receives feedback on key aspects that can help resolve issues related to vehicle safety, taking into account innovative developments and in accordance with the requirements of the authorities.

Written comments must be sent by February 1, 2021 to the Federal portal of electronic lawmaking: http://www.regulations.gov. Comments should refer to the case number: NHTSA-2020-0106.

Prerequisites for creating a draft law

The Department came to work on this document after collecting large amounts of data and statistics in the field of driverless transport. The first Federal vehicle safety standards were adopted back in 1966, and even then the Department had statistical data on accidents that allowed it to determine regulations to reduce the number of accidents. Today, there is much more data on road accidents, but there is not enough data to develop driver assistance systems and other safety systems.

Developing standards for ADS is more difficult for a number of reasons:

  • There are no vehicles with ADS that management can test and draw conclusions from
  • There is no operational data that management can analyze
  • Ride automation technologies are rapidly developing, which means that safety standards may become outdated in 10 years
  • The Department doesn’t have enough technical expertise to develop its own ADS

Challenges facing NHTSA

NHTSA, as they say, was caught between a rock and a hard place. There is already criticism in the public field, which says that the document published by the office is too weak, loyal to the automotive industry, and also does not contain technical details and safety rules.

Some of these comments are valid, but they do not take into account the constraints that the office has had to deal with – limited budget, lack of technical resources, and political issues.

Management needs to enlist the support of ride-hailing companies, because they are the ones who have the experience and knowledge of technical aspects, and because this market will continue to develop. NHTSA will be on the right track if it develops security standards for ADS together with the developers of these systems.

Management’s approach to standards development

NHTSA has been engaged in research on driverless driving technologies and has published several publications on this topic. Most of these publications are devoted to what requirements are relevant to the safety of vehicles with ADS. The Department also develops and adapts testing procedures for vehicles with ADS.

How management defines ADS

ADS is hardware and software that together can perform the task of dynamic driving, regardless of the limitations associated with the vehicle’s workspaces.

In less technical terms, ADS provides driving and control functions in the situations that the system is designed for.

What is included in the security standards for ADS?

The NHTSA bill is a complex 64-page document with details about regulatory restrictions, technical details, an analysis of what didn’t work, a discussion of the ADS framework, and security rules that will be implemented in the future. Management closely monitors the impact of technological progress on innovation and strives not to hinder it.

The figure below shows a General picture of what is included in the ADS security standards formulated by NHTSA. Management relies on the research and expertise of companies involved in ADS (automotive and high-tech). The left side shows the actions taken by the management (in black), and the right side shows the contribution of companies from the industry (in blue). The red block in the middle is a potential ADS security project.


The blocks in the figure above correspond to the main content of the document. The draft law identifies two main segments: technologies used in ADS, and administrative measures for implementing and controlling these systems. These segments have subsections shown in the figure:

  • Technical management research: research results and reports
  • Technical studies of industry representatives: an overview of the main technologies of driverless driving
  • Technical studies of industry representatives: proposed structure of the ADS security project
  • Research of technical processes in the industry (standards)
  • Administrative regulatory mechanisms
  • Administrative mechanisms: methods of interaction with the industry

The Department wants information from industry representatives and has included 25 questions in the comments. Comments are accepted until February 1, 2021. The prospects for each of the sections are shown in the figure below.

Technical management measures

NHTSA has done a lot of research to prepare for the development of ADS security standards. The Department has issued four reports:

  • 1.0 AV: Approaching of a revolution in the field of road safety (September 2016)
  • AV 2.0: security Concepts (September 2017)
  • AV 3.0: Preparing for the transport of the future (October 2018)
  • AV 4.0: Leading the U.S. industry in driverless driving technology (January 2020)

The Agency has launched its driverless vehicle transparency and safety initiative (AV Test) to provide the public with access to information about ADS development. 

NHTSA launched the AV Test in June 2020 with support from States, local governments, and private industry stakeholders. The website provides access to data on state activities, current legislation, regulations, ADS promotion measures, as well as data from companies involved in developing and testing ADS.

The NHTSA study focuses on driverless driving safety metrics and aims to identify methods, metrics, and tools for evaluating ADS performance. These estimates include the performance and behavior of systems relative to the declared workspaces and objects in them. Recognition capabilities, methods of responding to various events, and fault tolerance when leaving the work area are also evaluated.

The Department has developed several ADS security models and metrics. The ISM metric (instant safety metric) evaluates all physically possible trajectories along which a vehicle and other road users can move, taking into account a set of their possible actions. MPrISM (predictive model of instant security metrics) is an updated approach based on ISM and complements the evaluation method embedded in this metric.

Technical measurements of ADS performance in the industry: key technologies

Vehicles with ADS must perform all the driving functions that drivers perform: “feel” the behavior of other road users, perceive/understand their actions, plan the trajectory, build a path, monitor traffic, speed, and evaluate braking distance. A lot of research in the field of driverless driving is aimed at finding the right solutions for implementing these functions.

ADS engineering tests proposed by industry representatives

The office reviewed three ADS security models proposed by industry representatives. Mobileye offered its RSS (“security with responsibility”) model. RSS is a mathematical model that includes common-sense rules for interacting with other road users. The goal of this model is to minimize the probability of an accident when working within the usual behavioral expectations.

Nvidia offered a different model called Safety Force Field. This system uses numerical methods to assess situations through modeling – the system evaluates whether ADS successfully copes with the perception and control of the environment and does not take inappropriate actions.

In 2018, Rand released a report that proposed security models that looked at how ADS security can be defined and measured.

ADS industry security standards

ISO 26262 describes methods for evaluating functional safety in the development of electrical and / or electronic systems. This is the main standard for ADAS solutions and future ADS.

The ISO 21448 standard (Or “security of intended functions” – SOTIF) is designed to evaluate functions for which information awareness plays a crucial role (as well as for systems in which information awareness is provided through the use of complex sensors and processing algorithms, especially when it comes to emergency intervention systems). SOTIF does not apply to faults specified in ISO 26262.

UL 4600 is a technology standard that is intended for use by manufacturers when developing ADS – it was developed primarily for them.

Administrative arrangements: voluntary ADS security assessment measures

The AV 2.0 document published by the office introduces the concept of voluntary self-assessment of safety (VSSA). This document identifies 12 security factors that ADS developers should consider when developing and testing their systems. As of January 14, 2021, 26 companies have submitted their reports (see Voluntary Safety Self-Assessment | NHTSA)

NCAP also plays an important role in the standardization of security (especially ADAS). It makes sense to add ADS security assessments in new versions of the NCAP standards. For example, in new versions of their documents, you can implement an obstacle course test – data on its results will be useful for car buyers participating in the NCAP certification program.

Currently, the prospects for the development of ADS technology are unclear and depend on many future achievements and innovations. Consequently, the relevant regulatory performance indicators and safety thresholds remain unclear. That is why NHTSA seeks to improve safety through voluntary recommendations, rather than through strict regulations and requirements.

Administrative measures: regulations

NHTSA has already taken steps to ensure data disclosure and disclosure of exceptions to applicable regulations. An example of such a situation is the fact that Nuro was allowed to deploy vehicles with ADS for the transportation of goods.

The Department has broad legal powers in the field of vehicle safety and can apply them to ” reduce the number of accidents and deaths/injuries as a result of them.” NHTSA believes that at some point legal regulation of ADS will become a necessity and is exploring its ways. The Department can create new rules or change existing ones to regulate driverless vehicles.

The office usually used its authority in two ways:

  • Or to oblige companies to implement proven technologies in accordance with standards to meet safety requirements, as well as to customize technologies to meet minimum requirements.
  • Or to regulate voluntarily implemented technologies with minimal security requirements.

The office is also considering the possibility of introducing a new way of regulating standards due to rapid changes in the field of automotive technologies (these changes are associated with the development of automotive SOFTWARE and the introduction of over-the-air update technology). Next-generation road safety standards should provide developers of vehicles, sensors, software, and other technologies required for ADS with sufficient flexibility to change and improve their products without the need for constant adaptation of regulations.

NHTSA’s questions to the industry

Management wants companies from the industry to take an active part in the project and invites them to answer 25 questions. The deadline for submitting comments to the published draft is February 1, 2021. As of January 14, 16 comments had been submitted. A comment from the CTA (organizer of CES 2021) requested an extension of the submission deadline to March 3, 2021. The industry should make more efforts to share its experience in driverless driving with management and implement it in the new bill!

Evolution of the security project for ADS

The figure below shows an attempt to describe the prospects and make predictions about how the NHTSA ADS security standard may evolve. A number of blocks from the previous figure are shown on the left, and future forecasts are highlighted in red. There are a lot of questions about this project-they are presented in red and green blocks.


The big question is whether this project will be needed in such areas of ADS applications as Autonomous trucks, robotaxis, transportation of goods and, ultimately, ADS for consumers. There is another important issue that concerns how this project will develop in accordance with existing security standards. I think that these processes will occur in accordance with the figure above. After the Mobileye presentation at CES 2021 I added consumer ADS to the schema, but only in a level 4 context. Level 5 solutions will appear much later.

Another question concerns the self-government law passed by the House of representatives (but not the Senate) — what impact will it have in the future, when/if it is passed?

To sum up, I believe that the Office has made great efforts to conduct research and promote its safety assessment system, working in a challenging environment. Industry representatives should answer 25 questions presented in the document and apply their experience to improve the draft law.

In the following texts, I will analyze the NHTSA document on driverless vehicle safety standards in full detail.

Web site editor and tester.

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