Automotive ADAS Market Size, Share, Growth, and Industry Analysis, By Type (Adaptive Cruise Control (ACC), Lane Departure Warning (LDW) System, Park Assist, Blind Spot Detection, Others), By Application (Passenger Car, Light Commercial Vehicle (LCV), Heavy Commercial Vehicle (HCV)), Regional Insights and Forecast to 2035

Automotive ADAS Market Overview

The global Automotive ADAS Market size estimated at USD 124993.27 million in 2026 and is projected to reach USD 1507196.53 million by 2035, growing at a CAGR of 31.87% from 2026 to 2035.

The Automotive ADAS Market is expanding rapidly as vehicle manufacturers integrate advanced safety technologies to meet stricter road safety regulations and growing consumer demand for intelligent driving assistance. More than 92% of newly launched premium passenger vehicles now include at least one Advanced Driver Assistance System (ADAS) feature, while over 58% of mid-range vehicles are equipped with automatic emergency braking, adaptive cruise control, or lane departure warning systems. Camera-based ADAS solutions account for nearly 46% of installed systems globally, followed by radar technologies at approximately 34%. 

The United States remains one of the most influential Automotive ADAS Market regions due to strong vehicle safety regulations, widespread adoption of connected vehicles, and significant investments in autonomous driving technologies. More than 72% of newly registered passenger vehicles include forward collision warning systems, while nearly 68% feature automatic emergency braking. Around 65% of luxury vehicles sold in the U.S. are equipped with Level 2 driving assistance capabilities. More than 35 states permit autonomous vehicle testing under regulated conditions, supporting innovation across OEMs and technology companies. 

Key Findings

• Key Market Driver: More than 81% of governments have strengthened vehicle safety regulations, while approximately 74% of consumers prioritize advanced safety features during vehicle purchases. Nearly 69% of OEM investments target ADAS technologies, and 63% of automotive suppliers continue expanding sensor production capacity.
• Major Market Restraint: Nearly 41% of vehicle manufacturers identify semiconductor shortages as a production constraint, while 38% report increased sensor integration costs. Approximately 35% of consumers consider ADAS-equipped vehicles relatively expensive, and 29% remain concerned about repair costs.
• Emerging Trends: Around 66% of new vehicle platforms integrate AI-enabled perception systems, 61% utilize high-resolution radar, 54% include driver monitoring cameras, and approximately 47% feature over-the-air software updates supporting continuous ADAS improvements.
• Regional Leadership: North America accounts for approximately 33% of global ADAS adoption, Europe 30%, Asia-Pacific 29%, while Latin America and the Middle East & Africa together contribute nearly 8% of installations across vehicle production.
• Competitive Landscape: More than 72% of global ADAS technology development is concentrated among the top automotive suppliers, while approximately 67% of OEM partnerships involve sensor manufacturers. Nearly 59% of product launches focus on AI-enhanced perception and automated safety technologies.
• Market Segmentation: Passenger vehicles contribute approximately 79% of ADAS installations, commercial vehicles 21%. Camera-based solutions account for 46%, radar 34%, LiDAR 8%, and ultrasonic technologies approximately 12% of integrated systems.
• Recent Development: Nearly 64% of newly introduced ADAS platforms feature AI-assisted decision-making, 52% support cloud connectivity, 48% integrate enhanced driver monitoring, and approximately 44% enable software-based feature upgrades through over-the-air updates.

Automotive ADAS Market Latest Trends

The Automotive ADAS Market Trends are increasingly driven by artificial intelligence, machine learning, and advanced sensor fusion technologies. Nearly 66% of newly developed vehicle platforms now combine radar, cameras, ultrasonic sensors, and LiDAR to improve environmental perception. Around 57% of vehicle manufacturers are integrating driver monitoring systems capable of detecting fatigue and distraction using infrared cameras. Automated emergency braking adoption exceeds 70% among premium vehicle manufacturers, while adaptive cruise control installation has crossed 62% across newly launched passenger vehicles. These developments continue strengthening the Automotive ADAS Market Growth, Automotive ADAS Market Forecast, and Automotive ADAS Market Research Report.

Software-defined vehicles have become another defining trend in the Automotive ADAS Market. More than 53% of OEMs now provide over-the-air software updates for ADAS enhancements, reducing maintenance requirements and improving feature performance. Approximately 49% of automotive manufacturers are investing in centralized computing architectures replacing distributed electronic control units. Vehicle-to-everything (V2X) communication is expanding, with over 31% of new intelligent mobility projects incorporating connected infrastructure. AI-powered predictive safety systems demonstrate detection accuracy exceeding 90% under controlled testing environments, supporting wider deployment of semi-autonomous driving capabilities across passenger and commercial vehicles.

Automotive ADAS Market Dynamics

DRIVER

"Rising Demand for Intelligent Vehicle Safety Systems"

The primary driver of the Automotive ADAS Market is the increasing implementation of mandatory vehicle safety regulations and consumer preference for advanced protection technologies. More than 84% of fatal road accidents are associated with human error, encouraging governments to promote collision avoidance technologies. Nearly 73% of global OEMs have expanded ADAS integration across multiple vehicle segments. 

RESTRAINTS

"High Sensor Integration and Maintenance Costs"

High production costs remain a significant restraint for the Automotive ADAS Market. Camera modules, radar sensors, LiDAR units, and high-performance processors substantially increase manufacturing expenses. Approximately 43% of vehicle manufacturers report supply chain challenges affecting semiconductor availability. Around 39% indicate calibration complexity increases maintenance requirements after vehicle repairs.

OPPORTUNITY

"Expansion of Connected and Autonomous Mobility"

The expansion of connected transportation and autonomous driving technologies presents substantial opportunities within the Automotive ADAS Market. More than 61% of global automotive technology investments focus on intelligent mobility solutions. Approximately 56% of vehicle development programs now include AI-supported perception algorithms. Vehicle-to-everything communication deployment has increased across smart transportation initiatives. 

CHALLENGE

"Cybersecurity and Functional Safety Compliance"

Cybersecurity, software validation, and functional safety remain major challenges for the Automotive ADAS Market. Nearly 52% of connected vehicle developers identify cybersecurity as a primary engineering priority. Approximately 45% of software development resources are allocated toward safety validation and system verification. More than 37% of OEMs report increasing software complexity as additional sensors and AI functions are integrated into vehicles. 

Automotive ADAS Market Segmentation

The Automotive ADAS Market is segmented by type and application to address varying vehicle safety requirements across passenger and commercial transportation. By type, the market includes Adaptive Cruise Control (ACC), Lane Departure Warning (LDW) System, Park Assist, Blind Spot Detection, and Others. Camera-based systems contribute nearly 46% of ADAS installations, while radar-equipped technologies account for approximately 34%. By application, Passenger Cars represent the largest deployment segment with nearly 79% of installations, followed by Light Commercial Vehicles at around 14% and Heavy Commercial Vehicles at approximately 7%, reflecting increasing adoption of intelligent safety systems across every vehicle category.

BY TYPE

Adaptive Cruise Control (ACC): Adaptive Cruise Control (ACC) represents one of the most widely adopted technologies within the Automotive ADAS Market because it significantly improves highway driving safety and driver convenience. ACC utilizes radar sensors, cameras, ultrasonic sensors, and advanced electronic control units to automatically maintain a safe following distance from surrounding vehicles. More than 68% of premium passenger vehicles now integrate Adaptive Cruise Control as a standard safety feature, while approximately 44% of mid-range vehicle platforms also include the technology. Nearly 72% of long-distance drivers identify adaptive speed management as one of the most valuable driver assistance functions. Radar sensors used by ACC systems can detect vehicles more than 200 meters ahead with object recognition accuracy exceeding 95% under normal weather conditions. 

Lane Departure Warning (LDW) System: Lane Departure Warning systems have become essential components of modern vehicle safety because lane departure contributes to a significant percentage of highway accidents worldwide. Nearly 61% of newly produced passenger vehicles now include LDW functionality either as standard equipment or optional packages. Camera-based lane recognition systems achieve detection accuracy exceeding 94% under clear road marking conditions. Approximately 58% of ADAS software development investments now focus on improving lane detection performance using artificial intelligence and machine learning technologies. Advanced LDW systems monitor steering behavior more than 30 times every second, providing immediate alerts whenever unintended lane movement is detected. 

Park Assist: Park Assist systems continue gaining popularity as urbanization increases vehicle density and parking availability becomes more limited across metropolitan regions. Nearly 56% of premium vehicles and approximately 35% of mid-range passenger vehicles now incorporate automated parking assistance. Ultrasonic sensors account for more than 62% of parking assistance hardware installations, while camera-based surround-view systems represent nearly 48% of integrated solutions. Modern Park Assist technology detects parking spaces with recognition accuracy approaching 96% under standard operating conditions. Around 53% of consumers consider automated parking among the most practical ADAS functions for daily driving. Automated steering assistance reduces parking maneuver time by approximately 28%. 

Blind Spot Detection: Blind Spot Detection (BSD) has become one of the fastest-growing safety technologies in the Automotive ADAS Market due to its ability to reduce side-impact collisions and improve driver awareness during lane changes. The system uses radar sensors, ultrasonic sensors, and high-resolution cameras to monitor adjacent lanes and detect vehicles located in blind zones. Nearly 59% of newly manufactured passenger vehicles now include Blind Spot Detection either as standard equipment or optional safety packages. Premium vehicle adoption exceeds 82%, while nearly 43% of mid-range vehicles integrate BSD technology. Radar sensors used for blind spot monitoring typically detect vehicles at distances of more than 70 meters with object recognition accuracy exceeding 95%. 

Others: The Others segment includes Automatic Emergency Braking (AEB), Driver Monitoring Systems (DMS), Traffic Sign Recognition (TSR), Forward Collision Warning (FCW), Rear Cross Traffic Alert (RCTA), Night Vision Assistance, Adaptive Headlights, and Driver Fatigue Monitoring. These technologies collectively account for nearly 38% of integrated Advanced Driver Assistance System installations worldwide. Automatic Emergency Braking alone is installed in more than 71% of premium vehicles and approximately 49% of newly launched passenger cars. Driver Monitoring Systems are expanding rapidly, with installation rates approaching 45% because regulators increasingly emphasize distraction and fatigue detection. 

BY APPLICATION

Passenger Car: Passenger Cars represent the largest application segment in the Automotive ADAS Market, accounting for nearly 79% of total ADAS installations worldwide. Consumer demand for improved vehicle safety, enhanced driving comfort, and intelligent mobility solutions continues supporting widespread deployment across hatchbacks, sedans, SUVs, and luxury vehicles. More than 72% of premium passenger cars include Automatic Emergency Braking, Adaptive Cruise Control, Lane Departure Warning, and Blind Spot Detection as standard equipment. Approximately 61% of newly introduced SUVs feature Level 2 driver assistance capabilities integrating multiple ADAS technologies. Camera systems account for nearly 48% of passenger vehicle sensor installations, while radar contributes approximately 36%.

Automotive ADAS Market Regional Outlook

The Automotive ADAS Market demonstrates strong regional expansion as automotive manufacturers, technology providers, and regulatory bodies continue prioritizing advanced vehicle safety solutions. North America leads adoption with approximately 33% market share due to high penetration of connected vehicles, advanced automotive infrastructure, and strong demand for automated driving features. Europe contributes nearly 30% market share supported by strict vehicle safety standards and widespread premium vehicle production. Asia-Pacific represents around 29% market share, driven by increasing vehicle production, rising consumer awareness, and rapid technology adoption in China, Japan, and South Korea. 

NORTH AMERICA

North America represents the leading regional contributor to the Automotive ADAS Market, accounting for approximately 33% of global market share due to strong demand for vehicle safety technologies and rapid adoption of intelligent mobility solutions. The region benefits from high penetration of passenger vehicles equipped with adaptive cruise control, automatic emergency braking, lane departure warning, and blind spot detection systems. More than 72% of newly registered premium vehicles in North America include multiple ADAS features, while approximately 68% of newly manufactured passenger vehicles are equipped with automatic emergency braking capabilities. The United States contributes the majority of regional adoption, supported by advanced automotive manufacturing facilities and increasing deployment of autonomous vehicle testing programs. Around 61% of newly produced vehicles in the region utilize radar-based sensing technology, while camera-based ADAS systems account for nearly 48% of installations. Canada is also witnessing increased adoption, with more than 55% of new passenger vehicles integrating advanced safety assistance functions. The presence of major automotive technology developers, strong consumer preference for safety-enhanced vehicles, and increasing demand for Level 2 automated driving systems continue strengthening the Automotive ADAS 

EUROPE

Europe holds approximately 30% share of the Automotive ADAS Market, making it one of the most technologically advanced regions for intelligent vehicle safety solutions. The region benefits from strict automotive safety regulations, strong premium vehicle manufacturing capabilities, and increasing consumer demand for automated driving assistance. More than 70% of newly launched European passenger vehicles include at least one ADAS function, while advanced braking and lane assistance systems are becoming standard features across multiple vehicle categories. Germany, France, the United Kingdom, and Italy represent major contributors due to established automotive manufacturing ecosystems and strong investment in vehicle automation technologies. Camera-based ADAS solutions account for nearly 45% of regional installations, while radar technologies contribute approximately 35%. Around 62% of premium vehicles produced in Europe feature adaptive cruise control and advanced collision prevention technologies. European automotive manufacturers are increasingly integrating artificial intelligence, sensor fusion, and vehicle connectivity platforms to improve driving safety and automation capabilities. Nearly 58% of new electric vehicles launched in Europe include advanced driver monitoring and automated parking systems. 

GERMANY Automotive ADAS Market

Germany represents one of the most influential countries within the European Automotive ADAS Market, supported by its strong automotive manufacturing ecosystem, premium vehicle production, and continuous investment in intelligent mobility technologies. Germany accounts for approximately 12% of the global Automotive ADAS Market share and nearly 40% of Europe’s premium vehicle ADAS adoption. More than 78% of newly produced luxury vehicles in Germany include advanced driver assistance features such as Adaptive Cruise Control, Lane Departure Warning, Automatic Emergency Braking, and Blind Spot Detection. German automotive manufacturers are increasingly integrating artificial intelligence, radar sensors, LiDAR systems, and camera-based perception technologies into next-generation vehicles. Around 65% of new passenger vehicles produced in the country feature Level 2 driving assistance capabilities. More than 55% of automotive technology research programs focus on improving autonomous driving functions and software-defined vehicle platforms. The country has a strong testing infrastructure for autonomous vehicles, supporting innovation in urban mobility and highway assistance systems. 

UNITED KINGDOM Automotive ADAS Market

The United Kingdom Automotive ADAS Market is expanding steadily due to increasing adoption of vehicle safety technologies, connected mobility solutions, and autonomous driving research initiatives. The country contributes approximately 7% of the global Automotive ADAS Market share and represents one of the important European markets for intelligent vehicle technologies. More than 68% of newly registered passenger vehicles in the United Kingdom include at least one advanced driver assistance feature. Automatic Emergency Braking adoption exceeds 62%, while Lane Departure Warning systems are installed in nearly 58% of new vehicles. Growing demand for electric vehicles has accelerated ADAS integration, with approximately 54% of newly introduced electric models featuring multiple safety assistance functions. Automotive manufacturers and technology developers in the region are focusing on artificial intelligence-based perception systems, driver monitoring solutions, and connected vehicle communication technologies. Around 47% of automotive technology development projects involve improving autonomous driving capabilities and real-time decision-making systems. 

ASIA-PACIFIC

Asia-Pacific represents one of the fastest-growing regions in the Automotive ADAS Market, accounting for approximately 29% of global market share due to rapid vehicle production expansion, increasing technology adoption, and rising demand for safer transportation systems. The region benefits from strong automotive manufacturing capabilities across China, Japan, South Korea, and India. More than 64% of newly manufactured passenger vehicles in Asia-Pacific are equipped with at least one ADAS function, while premium vehicle adoption exceeds 75%. China contributes the largest regional share, supported by high vehicle production volumes and significant investments in intelligent mobility technologies. Japan continues strengthening the market through advanced automotive engineering and early adoption of autonomous driving solutions. Camera-based ADAS systems account for nearly 47% of regional installations, while radar technologies represent approximately 33%. Around 59% of electric vehicles produced in Asia-Pacific integrate advanced safety assistance features, including automated parking, adaptive cruise control, and driver monitoring systems. Automotive manufacturers across the region are investing heavily in artificial intelligence, semiconductor technologies, and sensor fusion platforms to improve vehicle automation. More than 52% of new vehicle development programs include software-based ADAS enhancements and connected vehicle capabilities. 

JAPAN Automotive ADAS Market

Japan represents a highly advanced market within the Automotive ADAS Market due to its strong automotive engineering capabilities, aging population concerns, and early adoption of intelligent vehicle safety technologies. Japan contributes approximately 9% of the global Automotive ADAS Market share and remains one of the leading countries in Asia-Pacific for automated driving technology development. More than 74% of newly manufactured passenger vehicles in Japan include advanced driver assistance functions such as Adaptive Cruise Control, Lane Departure Warning, Automatic Emergency Braking, and Parking Assistance. Japanese automotive manufacturers have significantly expanded investments in artificial intelligence, sensor fusion, and autonomous driving platforms, with nearly 60% of new vehicle development programs incorporating advanced safety software. Camera-based ADAS systems represent approximately 49% of installations in Japan, while radar technologies contribute nearly 34%. Around 68% of premium vehicles sold in the country feature Level 2 driving assistance capabilities. Driver monitoring systems are gaining adoption, with installation rates exceeding 42% across newly launched intelligent vehicles. 

CHINA Automotive ADAS Market

China is the largest contributor to the Asia-Pacific Automotive ADAS Market, supported by its massive vehicle production capacity, rapid electric vehicle expansion, and strong government focus on intelligent transportation systems. China accounts for approximately 15% of the global Automotive ADAS Market share, making it one of the most significant markets for advanced driver assistance technologies. More than 63% of newly produced passenger vehicles in China include at least one ADAS feature, while electric vehicles demonstrate adoption rates exceeding 70% for intelligent safety technologies. Camera-based systems represent nearly 46% of ADAS installations, while radar-based solutions contribute approximately 35%. Around 58% of newly launched electric vehicles include advanced functions such as adaptive cruise control, automated parking, lane assistance, and driver monitoring systems. Chinese automotive manufacturers are increasing investments in artificial intelligence algorithms, autonomous driving platforms, and high-performance computing systems. More than 50% of smart vehicle development programs in China focus on improving perception accuracy, decision-making capabilities, and connected vehicle communication.

MIDDLE EAST & AFRICA

The Middle East & Africa region represents an emerging market within the Automotive ADAS Market, accounting for approximately 8% of global market share. Increasing adoption of luxury vehicles, growing investments in smart transportation infrastructure, and rising awareness regarding vehicle safety technologies are supporting regional expansion. Countries such as the United Arab Emirates, Saudi Arabia, and South Africa are witnessing higher demand for advanced driver assistance features due to increasing vehicle modernization initiatives. More than 55% of premium vehicles sold in major Middle Eastern markets include technologies such as Adaptive Cruise Control, Blind Spot Detection, and Automated Parking Assistance. Radar-based ADAS systems account for nearly 36% of regional installations, while camera-based technologies represent approximately 44%. Around 42% of newly introduced vehicles in urban areas feature collision warning and driver assistance functions. Smart city development projects across the region are encouraging integration of connected vehicles and intelligent transportation systems. Saudi Arabia and the UAE are investing in autonomous mobility testing, with nearly 35% of smart transportation programs including ADAS-related technologies. 

List of Key Automotive ADAS Market Companies

• Continental AG
• Delphi Automotive PLC
• Robert Bosch GmbH
• Autoliv Inc
• Denso Corporation
• Valeo
• Magna International
• Mobileye NV
• TASS International

Top Two Companies with Highest Share

• Robert Bosch GmbH: Holds approximately 16% share in the Automotive ADAS Market due to its strong presence in radar sensors, braking systems, and intelligent vehicle safety solutions.
• Continental AG: Accounts for nearly 13% share supported by advanced camera systems, sensor technologies, and large-scale integration of ADAS solutions across passenger and commercial vehicles.

Investment Analysis and Opportunities

The Automotive ADAS Market is attracting significant investments as automotive manufacturers and technology providers focus on improving vehicle safety, automation, and connected mobility solutions. Nearly 68% of automotive technology investments are directed toward advanced sensing systems, artificial intelligence platforms, and software-based vehicle safety features. Around 62% of industry participants are increasing spending on radar, camera, and sensor fusion technologies to improve environmental perception accuracy. More than 55% of automotive companies are prioritizing Level 2 and Level 2+ automated driving capabilities. 

Future opportunities in the Automotive ADAS Market are concentrated around artificial intelligence, autonomous mobility, and connected vehicle ecosystems. Nearly 57% of automotive research programs focus on improving machine learning algorithms, object detection, and predictive safety systems. Around 51% of manufacturers are developing centralized computing architectures to support advanced driver assistance functions. Commercial vehicle operators represent another opportunity area, with approximately 44% of fleet companies evaluating ADAS technologies for improving driver safety and operational efficiency. Emerging markets are also creating new investment opportunities, as nearly 38% of vehicle manufacturers in developing regions are increasing adoption of intelligent safety technologies.

New Products Development

New product development in the Automotive ADAS Market is focused on improving sensor performance, artificial intelligence capabilities, and real-time vehicle decision-making. Approximately 64% of newly developed ADAS platforms integrate advanced sensor fusion technology combining cameras, radar, and ultrasonic systems. Around 52% of automotive technology companies are developing AI-powered perception systems capable of identifying pedestrians, vehicles, and road conditions with improved accuracy. More than 48% of new vehicle safety solutions include enhanced driver monitoring functions using infrared cameras and machine learning algorithms. Manufacturers are also introducing compact sensor modules designed for electric and autonomous vehicles, with nearly 45% of new products targeting software-defined vehicle architectures.

The development of next-generation ADAS products is increasingly focused on affordability, scalability, and integration across different vehicle categories. Nearly 56% of automotive suppliers are working on modular ADAS solutions suitable for passenger cars, light commercial vehicles, and heavy commercial vehicles. Approximately 49% of new product launches involve improved radar technology with extended detection range and higher accuracy. Driver assistance systems supporting automated parking, highway assistance, and collision prevention represent nearly 60% of current product innovation activities. Continuous improvement in semiconductor performance, edge computing, and cloud-connected vehicle platforms is enabling manufacturers to introduce more reliable and efficient Automotive ADAS Market solutions for global automotive customers.

Five Recent Developments

• Robert Bosch GmbH Advanced ADAS Platform Development: The company expanded its intelligent driving technology portfolio by focusing on AI-based safety systems and improved sensor integration. Approximately 60% of its latest automotive technology programs emphasize enhanced perception capabilities, automated assistance functions, and software-driven vehicle safety improvements.
• Continental AG Next-Generation Sensor Technology: Continental introduced advanced sensing solutions designed for improved vehicle environment detection. Nearly 55% of its recent ADAS technology developments focus on radar and camera integration, supporting higher accuracy in collision prevention, lane assistance, and automated driving applications.
• Mobileye NV Artificial Intelligence Driving Solutions: Mobileye strengthened its computer vision-based ADAS solutions by expanding AI processing capabilities. Around 65% of its technology improvements focus on enhanced object recognition, autonomous driving assistance, and real-time decision-making for intelligent vehicle platforms.
• Denso Corporation Vehicle Safety System Expansion: Denso increased development efforts for advanced driver assistance components, including cameras, radar sensors, and integrated control systems. Approximately 58% of new product initiatives focus on improving safety performance and supporting next-generation connected vehicle technologies.
• Valeo Automated Driving Technology Development: Valeo expanded its ADAS product portfolio with improvements in sensing and automated parking solutions. Nearly 50% of recent development activities focus on camera systems, driver assistance software, and intelligent mobility solutions for passenger and commercial vehicles.

Report Coverage of  Automotive ADAS Market 

The Automotive ADAS Market Report provides comprehensive analysis covering major technology segments, vehicle applications, regional performance, competitive landscape, investment trends, and product development activities. The report evaluates key ADAS technologies including Adaptive Cruise Control, Lane Departure Warning, Park Assist, Blind Spot Detection, Automatic Emergency Braking, and other intelligent safety systems. Approximately 46% of market analysis focuses on camera-based technologies, while radar systems represent nearly 34% of technology evaluation.

The Automotive ADAS Market Research Report also examines industry drivers, restraints, challenges, opportunities, and emerging trends influencing future market development. More than 70% of analysis focuses on safety regulations, autonomous driving advancements, artificial intelligence integration, and connected vehicle technologies. The competitive assessment includes major automotive technology providers contributing to approximately 72% of global ADAS innovation activities. The report evaluates sensor technologies, software platforms, vehicle automation levels, and customer adoption patterns across multiple automotive segments. Around 64% of newly introduced ADAS platforms incorporate AI-based decision-making capabilities, while nearly 53% support software-based updates and connected vehicle functions.