By Sandeep Kar

The low rollover stability of SUVs and heavy commercial vehicles is forcing automakers to incorporate rollover warning and control systems in these vehicle classes, which possess high rollover propensity. Increasing consumer awareness and concerns raised by the highway safety authorities regarding the poor roll stability limits of SUVs and heavy commercial vehicles is creating increasing pressure on automakers, Tier 1 OEMs and aftermarket participants to develop effective and comprehensive rollover warning and control systems.  Articulated vehicles, with their large weights and dimensions and consequentially high cg heights, are most susceptible to rollover related accidents than any other class of heavy vehicles. With approximately 1.8 million heavy commercial articulated trucks on US roads, there exists a potential market for rollover warning and control systems for articulated vehicles in the US. These systems can also be modified and incorporated to enhance the rollover stability of SUVs and mini-vans thereby offering greater growth potential in the long term.

High Rollover Propensity of Heavy Commercial Vehicles

Rollover is one of the primary causes of highway accidents involving articulated vehicles, causing loss of lives and property worth millions of dollars annually.  Studies on dynamics of heavy trucks have reported that the speeds considered safe by drivers during a steady turn are often close to the rollover threshold limits of the vehicles. Three percent of all crashes in American highways are caused due to rollover, which is the cause of 13 percent of all the fatal crashes involving heavy vehicles. However, it is responsible for one-third of the 43,200 deaths on U.S. highways each year according to NHTSA as shown in Figure 1.

Prevention Strategies

Prevention of rollover in heavy commercial vehicles can be realized through both active as well as passive rollover prevention strategies. Active rollover prevention strategies incorporate hydraulic actuators or active braking and keep the driver out of the control-loop, while passive control systems predicatively warn the driver of an impending rollover situation. Prevention of rollover through active control requires high forces and inertia and keeps the driver out of the loop, passive control strategies are thus considered as potential methods for rollover prevention in heavy vehicles. The impairment of the driver to sense lateral acceleration response raises the need for some form of warning to the driver when the lateral acceleration or other potential rollover indicator’s response approaches a threshold value. While the Static Rollover Threshold (SRT) and Static Safety Factor (SSF) have been used as rollover metrics by NHTSA and other agencies, these are static rollover metrics and inaccurately represent the rollover propensity of vehicles under dynamic directional maneuvers. The development of a dynamic rollover metric that is reliable, measurable and provides sufficient lead-time is required to support the warning and control algorithm.

The advances in low-cost micro-sensors, actuators, warning devices, and high-speed processors have culminated into seamless integration of various monitoring and control devices in vehicles.  Some concepts in roll dynamics monitoring for generating an early warning for the driver have been proposed. The proposed concepts however involve complex challenges in realizing a reliable monitoring device. These include the identification of key response variables related to onset of rollover, measurement, and processing of the variables to be monitored and development of a reliable warning algorithm with minimal probability for false warnings. The three basic stages of a predictive rollover warning strategy are shown in Figure 2.

Market Opportunity

The high mortality rate associated with rollover accidents, highway traffic obstructions and huge losses of property caused due to heavy vehicle rollover is a serious cause of concern in the automotive industry. The automakers are incumbent with intense pressure from consumers and highway traffic safety authorities alike to come up with rollover prevention systems that enhance the rollover stability of heavy commercial vehicles. The pressure on truck makers to incorporate rollover prevention devices is also increasing from transporters who are increasingly becoming aware of the poor rollover stability of heavy vehicles and the impact of rollover induced accidents on their operations.

Given the concerns raised by NHTSA, DOT, public organizations, and transporters, there exist possibilities for the US/Canadian governments to enforce strict rollover stability criteria for heavy trucks. This would create huge pull from the automakers for the rollover warning and control devices to enhance the rollover stability of these vehicles. With nearly two million tractor semi-trailer circulating on US roads, this presents huge opportunities for automotive OEMs and aftermarket participants. Innovative and effective rollover warning and control devices, developed by the participants in this market can help them make headway into the emerging and potentially huge market. These systems, owing to their safety enhancing appeal are guaranteed to be accepted by a broad segment of the market. At the moment the disagreement on a standard rollover stability metric and the fear of litigations for possible failure of the warning and control system is acting as the major impediment towards introduction of these systems in the market. However, truck-makers and component manufacturers are actively conducting research into the development of such devices.

 The integration of rollover warning devices with onboard infotainment and navigation systems presents value addition proposition for the automotive infotainment and navigation market. The operation of a warning and control algorithm requires basic signal processing and infotainment and navigation systems hardware/software architecture can be modified to incorporate the rollover warning and control algorithm.  This would reduce the form factor for the warning device and enhance the value proposition of the infotainment and navigation system, using it hardware platform for providing audio/visual warning to the driver whenever an impending rollover situation is detected.

Conclusions

Increasing safety concerns being raised by a variety of organizations and highway safety authorities is resulting in high importance been attached to prevention of rollover related accidents in US and Canada. Great opportunities exist for both the OE and the aftermarket participants to come up with rollover warning and control devices either as independent systems or incorporated with the infotainment hardware/software platform. The challenges to the market are in the form of non-agreement in the automotive industry regarding a generally accepted and standard rollover metric and active-control mechanism. Rapid progress in research and development pertinent to rollover warning and control as well as consistent pull from consumers and automakers is presenting great opportunities for OEMs and aftermarket manufacturers to develop and market rollover prevention and control devices.

The large population of heavy trucks that are susceptible to rollover related accidents coupled with great pull from the market for rollover prevention devices across all vehicle segments presents a sizeable market potential for these stability enhancement devices. It is expected that the high safety value associated with these devices coupled with the pull from automakers would drive this market’s growth. Based upon the success of these systems in the heavy tucks segment of the automotive industry, these systems can also be modified to be made applicable in SUVs and mini-vans thereby offering the participants a huge market potential in the medium-long term perspective.