Volvo’s City Safety
A new study by the Highway Loss Data Institute (HLDI) found that Volvo XC60 midsize SUVs outfitted with a standard collision-avoidance feature called City Safety are far less likely to be involved in low-speed crashes than comparable vehicles without the system. City Safety is designed to help a driver avoid rear-ending another vehicle in slow-moving, heavy traffic.
Volvo and other automakers also offer optional forward collision warning systems designed to help drivers avoid crashes at higher speeds than City Safety does; City Safety addresses more common crashes than higher-speed systems do and has been standard on XC60s since the 2010 model year. It also is standard on 2011-12 S60 sedans and 2012 model S80 sedans and XC70 wagons.
City Safety automatically brakes to avoid a front-to-rear crash in certain low-speed conditions. It uses an infrared laser sensor built into the windshield to monitor the area in front of the SUV when traveling at speeds of about 2 to 19 mph. It detects and reacts to other vehicles within 18 feet of the XC60’s front bumper during both daytime and nighttime driving.
If the speed difference between vehicles is less than 9 mph, City Safety helps drivers avoid some crashes altogether. If the difference is between 9 and 19 mph, the feature may not prevent the crash but will reduce the consequences. It’s not designed to work at speeds faster than 19 mph.
Unlike forward collision warning systems developed to address higher-speed crashes, City Safety doesn’t alert the driver before it engages and brakes at the last instant if the driver doesn’t react in time.

Combined V2V and V2I systems could potentially address about 81% of all-vehicle target crashes, 83% percent of all light-vehicle target crashes, and 72% percent of all heavy-truck target crashes annually.

In addition to the technical challenges of developing V2V or V2I systems, there are also significant deployment challenges related to cost, driver behavior and the legacy vehicle parc. There is an extensive body of work on connected vehicle research, and some background is required before coming back to Ford.

Background

US DOT Connected Vehicles Research. The US Department of Transportation (DOT) sponsors a broad program of connected vehicle research; the research is a multimodal program that involves using wireless communication between vehicles, infrastructure, and personal communications devices to improve safety, mobility, and environmental sustainability. The work is divided into four main areas: Technology, Applications, Technology Policy and Institutional Issues, and Use of Dedicated Short Range Communications (DSRC).

Applications are grouped into three main areas:

• Connected vehicle safety applications are designed to increase situational awareness and reduce or eliminate crashes through vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) data transmission that supports: driver advisories, driver warnings, and vehicle and/or infrastructure controls. These technologies may potentially address up to 82% of crash scenarios with unimpaired drivers, preventing tens of thousands of automobile crashes every year (further research will incorporate heavy vehicle crashes including buses, motor carriers, and rail).

• Connected vehicle mobility applications provide a connected, data-rich travel environment. The network captures real-time data from equipment located on-board vehicles (automobiles, trucks, and buses) and within the infrastructure. The data are transmitted wirelessly and are used by transportation managers in a wide range of dynamic, multi-modal applications to manage the transportation system for optimum performance.

• Connected vehicle environmental applications both generate and capture environmentally relevant real-time transportation data and use this data to create actionable information to support and facilitate “green” transportation choices. They also assist system users and operators with transportation alternatives or options, thus reducing the environmental impacts of each trip.

  Data generated from connected vehicle systems can also provide operators with detailed, real-time information on vehicle location, speed, and other operating conditions. This information can be used to improve system operation. On-board equipment may also advise vehicle owners on how to optimize the vehicle’s operation and maintenance for maximum fuel efficiency.

The current DOT strategy is to prepare the National Highway Traffic Safety Administration (NHTSA) for an agency decision in 2013. This decision will determine whether the agency proceeds with regulatory activities that could require this technology on new vehicles, consumer information programs that help new car buyers understand the effectiveness of this technology, or the need for further research and development.

V2V Communications for Safety. DOT has been conducting research with automotive manufacturers since 2002 in order to assess the feasibility of developing effective crash avoidance systems that utilize vehicle-to-vehicle communications. Vehicle-to-Vehicle Communications for Safety is the dynamic wireless exchange of data between nearby vehicles that offers the opportunity for significant safety improvements. By exchanging anonymous, vehicle-based data regarding position, speed, and location (at a minimum), V2V communications enables a vehicle to:

• sense threats and hazards with a 360 degree awareness of the position of other vehicles and the threat or hazard they present;
• calculate risk;
• issue driver advisories or warnings; or
• or take pre-emptive actions to avoid and mitigate crashes.

At the heart of V2V communications is a basic application known as the “Here I Am” data message. This message can be derived using non-vehicle-based technologies such as GPS to identify location and speed of a vehicle, or vehicle-based sensor data wherein the location and speed data is derived from the vehicle’s computer and is combined with other data such as latitude, longitude, or angle to produce a richer, more detailed situational awareness of the position of other vehicles.

DOT notes that because the Here I Am data message can be derived from non-vehicle-based technologies that are ubiquitous within the marketplace (e.g., smartphones), the ITS Program may leverage an opportunity to accelerate V2V capability and deployment in the near-term and produce safety benefits through reduced crashes sooner than through Original Equipment Manufacturer(OEM) embedded systems only.

DOT’s vision for V2V is that eventually, each vehicle on the roadway (inclusive of automobiles, trucks, buses, motor coaches, and motorcycles) will be able to communicate with other vehicles and that this rich set of data and communications will support a new generation of active safety applications and safety systems.

V2V Communications for Safety is a key component in the DOT’s Vehicle to Vehicle Communications program, and is complemented by research programs that support connectivity among vehicles and infrastructure (V2I) and among vehicles and consumer devices (V2D) to deliver safety and mobility benefits.

On the seven-layer ISO protocol stack model, DSRC occupies stacks 1–2—the Physical and Data Link layers—as does IEEE 802.11p, another standard that can be applied in V2V communications. Source: Weigle 2008. Click to enlarge.

DSRC. DSRC (Dedicated Short Range Communications) is a two-way short- to- medium-range wireless communications capability that permits very high data transmission critical in communications-based active safety applications. In Report and Order FCC-03-324, the Federal Communications Commission (FCC) allocated 75 MHz of spectrum in the 5.9 GHz band for use by Intelligent Transportations Systems (ITS) vehicle safety and mobility applications.

In the US, DSRC refers generically to communications on a dedicated 5.9 GHz frequency band reserved using the Wireless Access in Vehicular Environments (WAVE) protocols defined in the IEEE 1609 standard and its subsidiary parts. These protocols build on the established IEEE 802.11 standards for Wi-Fi wireless networking. Standard messages for DSRC are described in the SAE J2735 standard. These standards continue to evolve.

DSRC is suited to mobile vehicular applications needing high bandwidth and low latency in short range communications (on the order of a few hundred meters). Security is managed through a certificate management scheme that issues new certificates to each radio at regular intervals.

AASHTO

In 2009, AASHTO (American Association of State Highway and Transportation Officials) prepared its IntelliDrive Strategic Plan. Among the specific actions identified in the plan was the need to perform an analysis of the potential approaches for deploying the infrastructure components of Connected Vehicle systems by state and local transportation agencies. The plan also called for the identification of AASHTO’s role in all aspects of Connected Vehicle infrastructure deployment. A report published in June of this year provides the results of that analysis.

Referencing the 2010 NHTSA report, AASHTO consider improving transportation safety the keystone opportunity for Connected Vehicle deployment. In terms of more specific objectives, AASHTO said, applications contributing to improved safety would create results including:

• Reducing the likelihood of collisions at intersections;
• Reducing the likelihood of forward and lateral (lane change and merge) collisions;
• Reducing the likelihood of secondary crashes;
• Reducing the likelihood of road departure crashes; and
• Providing more accurate and timely road condition alerts.

One of the major downsides of V2V is time is would take to equip all cars, trucks, and buses to achieve these benefits. (As a result, some analysis has suggested that the addition of communications between in-vehicle equipment and a roadside infrastructure (vehicle-to-infrastructure or V2I communications) would allow some safety benefits of VII to be generated more quickly and could incentivize in-vehicle equipment deployments.)

In its 2011 report, AASHTO notes that USDOT’s original VII (Vehicle-Infrastructure Integration) approach assumed that DSRC would be required for all V2V and V2I communications. While the FCC had allocated the spectrum for safety applications, it allowed unused bandwidth to be applied to other uses, including mobility and convenience applications. Early assessments suggested that safety applications would not consume the entire available bandwidth, and, therefore, the program proceeded with an assumption that both safety and non-safety applications would be supported through this nationwide network of DSRC equipment.

However, newer deployment scenarios reflect a shift in subsequent thinking relating to the core wireless communications technologies that support V2V and V2I connectivity. During the course of the initial VII program, wireless technology and mobile communications devices proliferated, and telecommunications providers expanded bandwidth through 3^rd generation (3G) services to support high-speed transmission of text, voice, and video data. The subsequent Connected Vehicle programs, beginning in 2009, continue to emphasize DSRC with its high-speed, low-latency, secure data communications capability for V2V and V2I safety applications, AASHTO notes, but do acknowledge the potential of other communications approaches for non-safety applications, including mobility applications.

However, AASHTO continues in its report, compared to other wireless communications technologies, DSRC is still early in its development and application life cycle. Proof-of-concept demonstrations have been deployed in Michigan and California, but there are to date no widespread deployments. US DOT is currently developing a Safety Pilot Program for a large demonstration of V2V and V2I safety applications in 2011-2013.

The AASHTO report also notes that cellular network services, while ubiquitous, are not generally appropriate for real-time localized data exchange. Network latencies and the potential for dropped connections make cellular services inappropriate for real-time V2V and I2V safety applications.

The Wi-Fi family of technologies provide wireless communications to replace wired connections for local area networks; the protocols are described by the IEEE 802.11 standards. Wi-Fi is not specifically designed for vehicular applications, but has been used effectively to communicate between vehicles and fixed stations, such as parking lots and maintenance yards, AASHTO observes. Wi-Fi connections from vehicles to roadside collectors have been used in probe data collection applications in Michigan.

Ford

Ford has been looking at vehicle connectivity for a long time, says Mike Shulman, technical leader, Ford Research and Advanced Engineering, who focuses on the intelligent vehicle applications. Ford’s basic approach to connectivity is to leverage the customer smartphones where possible or appropriate; Ford’s SYNC technology (developed with Microsoft) exemplifies that approach. Using SYNC the in-vehicle system has the ability to do a hands-free, voice-activated phone call, or automatically call 911 in the case of an accident. (Ford is now also trialing an Operator Assist feature for the cloud-based network of SYNC Services, giving all registered Services users complimentary access to a live operator for help with business searches and address entry for turn-by-turn directions.)

SYNC represents a different approach than that taken by embedded systems, such as GM’s OnStar. The AASHTO report observes:

The relatively long average lifespan results in some interesting market dynamics for passenger vehicles, and consequently complex dynamics for the deployment of Connected Vehicle equipment. Specifically, any fixed equipment (including, for example, Connected Vehicle OBEs) sold on a passenger vehicle will be in use for an average of 12 years. The passenger vehicle market is also marked by rather long development cycles. A new vehicle platform takes about four years to develop. Typically the components used in the vehicle are “frozen” about one year into the development cycle. Given the comparatively fast lifecycle for consumer electronics equipment (about 18 months) this means that consumer electronics related equipment embedded in a vehicle (phone, radio, media interface, navigation, etc.) will be about 15 years (10 generations) old by the time the average vehicle is retired. In other words, the radios and other equipment are already a few years old before they have even reached the showroom floor.

A good example of this issue was the OnStar system, which initially used an analog cellular telephone. The first vehicles with this system were sold around 1997. In early 2003 the FCC announced a five-year “sunset”, after which the cellular providers would no longer be required to support the analog mobile phone system. Despite a request for delay, the so called “analog sunset” became effective in February 2008. Shortly thereafter most carriers ceased providing analog mobile phone service. At that point at least five years of GM production vehicles and about three years of Lexus vehicles were on the road using this system. The OnStar systems in those vehicles became obsolete on Feb 18, 2008.

Similar issues have occurred with iPod plugs, USB plugs, memory cards, navigation databases, hands-free systems, and other technological conveniences manufactured into passenger vehicles. In general the passenger vehicle industry is also exceedingly cost conscious...As a result, deploying Connected Vehicle equipment in vehicles requires that the system provides clear value to the vehicle user (such that a vehicle manufacturer can be sure that the added feature will provide value to the customer commensurate with the cost of the equipment). This value must be realizable by customers in a time frame that is relevant to their ownership of the vehicles (that is, they must realize its value while they own the car, and preferably when they are considering their vehicle purchase). These considerations are generally in conflict with the dynamics of the market. The time required to achieve sufficient penetration in the fleet, such that some benefits (value) are obvious to the owner, is longer than that which would motivate the installation (and cost) of the equipment.

—AASHTO Connected Vehicle Infrastructure Deployment Analysis

Ford’s current work on V2V communications for crash avoidance—as demonstrated at the Forward with Ford event—is built on DSRC; however, says Shulman, Ford also believes that a modified WiFi-type implementation for intelligent vehicles could be added to smartphones or GPS systems and connect to SYNC like today’s phones to accelerate the deployment of V2V and V2I applications.

There is handshaking that goes on with WiFi in general. We stripped away a lot of handshaking for these apps—we want to turn it into a broadcast message.

It’s not to say that one [communications] method is the right method, they all have their strengths and weaknesses. If you have two cars about to collide at an intersection, you need something with high availability and low latency on a dedicated channel. But if you’re broken down in Montana, you need a cell phone. We’re thinking about it in a more holisitic way, what applications can we deliver based on different systems.

— Mike Shulman

Specialized system such as forward-looking radar are not really built off of commercial technologies, Shulman notes, and the volumes are low.

It’s not something that would go into a Fiesta or Focus. We wanted to think about this right from the beginning as something that goes on all vehicles. WiFI is basically in laptops and smartphones and in the new SYNC vehicles. We just modify it a little bit.

—Mike Shulman

Among the intelligent vehicle applications Ford is exploring overall are:

• Expanded safety applications. Intelligent vehicles could warn drivers if there is a risk of collision when changing lanes, approaching a stationary or parked vehicle, or if another driver loses control. Drivers also could be alerted if their vehicle is on a path to collide with another vehicle at an intersection, when a vehicle ahead stops or slows suddenly, or when a traffic pattern changes on a busy highway.

• Green potential. By reducing crashes, intelligent vehicles could ease traffic delays, which would save drivers both time and fuel costs. Congestion also could be avoided through a network of intelligent vehicles and infrastructure that processes traffic and road information. A traffic management center would send this information to intelligent vehicles, which could then suggest less congested routes to drivers.

• Intersection assistance. Intelligent vehicles show great potential in assisting drivers in hazardous situations, such as intersections where the view is compromised in one or both directions. If the vehicles are able to communicate, the vehicle approaching the intersection will be aware of another approaching vehicle and alert the driver.

• Lane-passing assistance. Intelligent vehicles could help in lane-passing situations where the view is compromised. If vehicles approaching from opposite directions were communicating with each other, they could warn the drivers of oncoming vehicles, potentially avoiding head-on crashes

• Alternative routing. Intelligent vehicles could help reduce the billions of gallons of gas wasted in traffic jams each year. Vehicles experiencing road congestion could alert approaching vehicles to a problem by serving as traffic probes and signal their status to a roadside communication unit. These units would send the data to a traffic management center. The center would then report the congestion to other vehicles via advanced Wi-Fi—called dedicated short-range communication—or with cellular or satellite radio signals. The vehicles could use the information to suggest a new route to the drivers.

MIT and smart intersections

Ford has an ongoing research partnership with MIT in a number of areas, including safety. One of MIT’s projects includes work on a “smart intersection” to reduce collisions. MIT is working on include an algorithm underlying a V2V- and V2I-based Intelligent Transportation System that takes into account models of human driving behavior so that it can work effectively even in situations involving cars without the onboard system.

Accounting for the variable behavior of human drivers has been an ongoing challenge for ITS developers. According to Domitilla Del Vecchio, an assistant professor of mechanical engineering and W.M. Keck Career Development Assistant Professor in Biomedical Engineering at MIT, it is difficult to design a system that is safe without being overly conservative.

Building on the research of others who have modeled human driving behavior, Del Vecchio and researcher Rajeev Verma reasoned that driving actions fall into two main modes: braking and accelerating. Depending on which mode a driver is in at a given moment, there is a finite set of possible places the car could be in the future, whether a tenth of a second later or a full 10 seconds later. This set of possible positions, combined with predictive models of human driving—when and where drivers slow down or speed up around an intersection, for example—all went into building the new algorithm.

The result is a program that is able to compute, for any two vehicles on the road nearing an intersection, a “capture set,” or a defined area in which two vehicles are in danger of colliding. The ITS-equipped car then uses information from its onboard sensors as well as roadside and traffic-light sensors to try to predict what the other car will do, reacting accordingly to prevent a crash.

Del Vecchio and Verma tested their algorithm with a laboratory setup involving two miniature vehicles on overlapping circular tracks: one autonomous and one controlled by a human driver. Out of 100 trials, there were 97 instances of collision avoidance. The vehicles entered the capture set three times; one of these times resulted in a collision.

In the three “failed” trials, Del Vecchio says the trouble was largely due to delays in communication between ITS vehicles and the workstation, which represents the roadside infrastructure that captures and transmits information about non-ITS-equipped cars.

One way to handle this problem is to improve the communication hardware as much as possible, but the researchers say there will probably always be delays, so their next step is to make the system robust to these delays; that is, to ensure that the algorithm is conservative enough to avoid a situation in which a communication delay could mean the difference between crashing and not crashing.

The researchers have already begun to test their system in full-size vehicles with human drivers; future work will focus on incorporating driver reaction-time data to refine when the system must actively take control of the car and when it can merely provide a passive warning to the driver. They are also working on algorithms that can account for up to eight vehicles at once, to prevent a situation in which slowing down or speeding up to avoid one car could actually cause a collision with another.

Eventually, the researchers also hope to build in sensors for weather and road conditions and take into account car-specific manufacturing details — all of which affect handling — to help their system make even better informed decisions.

The theory behind the algorithm and some experimental results will be published in a forthcoming issue of the journal IEEE Robotics and Automation Magazine.

(Ford hosted Green Car Congress at the Forward with Ford event in June.)

Resources

• AASHTO Connected Vehicle Infrastructure Deployment Analysis (FHWA-JPO-11-090, June 2011)

• Achieving the Vision: from VII to IntelliDrive (US Department of Transportation RITA, ITS Joint Program Office, April 2010).

• Frequency of Target Crashes for IntelliDrive Safety Systems (DOT HS 811 381, October 2010)

• A Vehicle-to-Vehicle Communication Protocol for Cooperative Collision Warning

• Standards: WAVE / DSRC / 802.11p (Dr. Michele Weigle, Old Dominion University, 2008)

• DOT ITS Strategic Research Plan, 2010–2014