5 Things You Should Know about the DOT V2V Mandate

By John Blyler, Contributing Editor

The U.S. Department of Transportation is preparing to mandate how designers will develop vehicle-to-vehicle (V2V) communication systems. Here are five key things you should understand about this action:

1. It’s a proposed mandate.

The National Highway Traffic Safety Administration (NHTSA) has published a notice of proposed rulemaking for what could become the Federal Motor Vehicle Safety Standard (FMVSS) 150. If this proposed standard emerges without significant changes, all automotive manufacturers will have to install dedicated short-range communications (DSRC) systems in new light vehicles by about 2020.

The stated goal of the proposed mandate is to improve safety by enabling cars, trucks, buses, and other vehicles to share information and “talk” with each other. The NHTSA estimates that safety applications enabled by such technology could mitigate the severity of up to 80% of non-impaired crashes. This includes crashes at intersections or while changing lanes.

This graphic depicts examples of crash scenarios and V2V applications. (Courtesy of NHTSA)

This graphic depicts examples of crash scenarios and V2V applications. (Courtesy of NHTSA)

While the mandate encourages a market-based approach to application, some have questioned its capability to innovate upon the pre-selected DSRC platform.

2. DSRC is based on the IEEE 802.11p standard.

Dedicated short-range communications (DSRC) radios are based on a particular type of Vehicle-to-Vehicle (V2V) technology that falls under the IEEE 802.11p Wi-Fi standard.  IEEE 802.11p is an amendment to the IEEE 802.11 “Wi-Fi” standard that adds wireless access for V2V. Specifically, it includes data exchanges between high-speed vehicles and between the vehicles and the roadside infrastructure (so-called V2I communication).

DSRC is licensed in the ITS band of 5.9 GHz (5.85-5.925 GHz). These V2V radios are designed to send and receive short messages 10 times per second over a range of about 1,000 to 1,500 feet, depending on the conditions. DSRC shares vehicle information, such as position, heading, speed, and braking status, to help alert other vehicles of pending accidents and the like. This feature should complement vehicles’ existing autonomous camera, radar, and Lidar technologies to expand awareness beyond the range of any one vehicle’s sensors.

3. There are other approaches.

Remember the communication battles between wireless and cellular providers from the 3G era? Today’s V2V and V2X communications are the latest incarnation of those struggles. Currently, dedicated short-range communications and 5G cellular networks are taking the leading roles.

DSRC has the advantage in that radio platform modules already exist (e.g., General Motors’ 2017 Cadillac cars). Further, the U.S. Department of Transportation plans to require DSRC for all new light vehicles. Regulators in Europe have also embraced DSRC.

However, competitors to DSRC point out that the original IEEE 802.11 standard—the basis for the 802.11p update—was designed for relatively stationary Wi-Fi applications and not for millions of moving vehicles. Further, they note that the arrival of 5G next-generation cellular networks might be a choice for V2V and V2X communications. In addition to covering all V2V requirements, 5G cellular will also handle connections to devices like smart traffic lights, tolls, and other parts of the transportation infrastructure —so-called vehicle-to-everything or V2X communications. Finally, 5G also adds a mobile entertainment capability.

But 5G is not without its issues. For example, the 5G specification is still evolving. In addition, network lag and processing latencies—common in past “next-generation” cellular rollouts—would render the system unreliable for such a critical application. Cellular-based data access also would carry a significant price tag.

4. Government mandates don’t often end well.

The proposed DOT mandate bases V2V and V2I technologies on the DSRC architecture. But many of DSRC’s technical elements were mandated over a decade ago. As a result, they potentially underutilize current wireless technology.

It has been suggested that technology adoption works best when it comes from marketplace competition rather than technology imposition by governing bodies. History in the wireless space suggests that it’s better to avoid stringent device mandates that limit technology to a single choice. The result often sacrifices speed, performance, and power.

In the past, market processes in the communications space have created reliable and interoperable networks. For example, cellular phones without regulatory mandates use both interoperable elements (SMS messaging) and non-interoperable elements (CDMA vs. GSM, operating systems, etc.).

5. The future is a mix.

Ultimately, some combination of short-range and 5G communications may be necessary to make vehicle-to-vehicle connections work reliably. The value of dedicated short-range communications devices is the sharing of information between vehicles and—to some extent—infrastructure. 5G connectivity will complement DSRC while handling the connections to everything else including the Internet of Things (IoT). And there is still the possibility for the proposed DOT mandate to incorporate a broader realization of current wireless and cellular technologies.

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GE's infotainment benchDiagram showing stages of ADAS development.