Why modern cars are getting heavier and how it affects safety and efficiency

Modern cars are becoming heavier due to larger bodies, batteries, and comfort features. But how does this extra weight affect safety, energy use, and the environment? Discover what the latest research from CBS, KBA, IIHS, and ICCT reveals.

New cars are getting heavier — and that isn’t by accident. The average buyer is drifting away from tiny hatchbacks, while demand for electric vehicles with hefty battery packs is rising. Add in the popularity of SUVs and the push for more comfort and safety features — that’s a cocktail for increasing mass. But at what point does extra weight stop being an ally and start becoming a liability — in terms of fuel (or energy), environmental impact, and safety for others on the road? Let’s dig in.

Why modern vehicles are gaining weight

A recent report from the Netherlands’ statistics agency (CBS) reveals that over the last decade, the average mass of a passenger car increased by 94 kg. Meanwhile, cars are also growing in length and width. In Germany, data from KBA for 2025 show that SUVs are the dominant segment: in July, they accounted for 34.3 % of new registrations.

The main driver behind mass growth is the shift toward EVs and hybrids: battery packs themselves are heavy components, adding tens or even hundreds of kilograms to a platform. CBS explicitly points out that the rising share of EVs is seen in the upward pull on the average mass. Consumer demand also plays a role: the 2025 Global Automotive Consumer Study (Deloitte) shows a trend toward preferring larger bodies and SUVs in key markets.

One gap: in the last year, no reliable European studies quantitatively break down how much comfort or safety systems (extra insulation, sensors, actuators) contribute to weight gain. That kind of granularity is more common in older literature, which was excluded per factual criteria.

Weight and safety: advantages with caveats

Bigger doesn’t automatically mean safer. In a 2025 IIHS report, it’s noted that the protective benefit of added mass saturates beyond a certain point: additional weight yields diminishing returns, and after that, weight can harm others. Ultra-heavy vehicles may shield their own occupants somewhat better, but they become serious risks for other road users. Pedestrians and cyclists are especially vulnerable. That’s a major thread in criticisms from Euro NCAP and ETSC: growing size and mass reduce odds of safety for weaker parties in city collisions.

When IIHS released its September 2025 battery of ratings for seven electric vehicles, some heavy models scored well for occupant protection — but also took hits in scenarios assessing risk to others in collisions.

Weight and energy or fuel consumption

In EVs, weight often functions as a hidden cost: a 2025 Energy paper shows that mass has a significant influence on real-world energy consumption, especially under acceleration, on slopes, or at high speeds. For internal combustion and hybrid vehicles, recent studies provide statistical evidence linking mass to fuel consumption. The Netherlands government published a report (May 2025) comparing WLTP-certified consumption with real-world measurements for both passenger and light commercial vehicles. The gaps can be substantial — and heavier vehicles tend to exacerbate those disparities.

Ecology, life-cycle assessment, and the role of weight

In its July 2025 update, ICCT presents life-cycle analyses showing that, even with heavier battery packs and operational energy use, EVs in most scenarios still come out cleaner overall than fossil-fuel cars. But here’s the key caveat: efficiency — including weight control — remains a crucial lever. In Germany, the ifeu update (February 2025) echoes this: optimizing vehicle parameters (weight, aerodynamics, etc.) is essential to fully realize the environmental benefits of EVs. The IEA’s Global EV Outlook 2025 adds context, highlighting how mass, charging infrastructure density, range, and efficiency combine to shape the EV promise.

Policy, cities, and regulatory responses

Across the EU, regulatory pressure is mounting. In April 2025, the Commission rolled out updates to road safety regulation covering digital vehicle documentation, stronger periodic inspections, and modernization of registration procedures. Pedestrian safety is a focal point: recent amendments to the UN standard R127 address vehicles with large front-end geometries — a response to the trend of bulging, heavy masses. Cities are also pushing back: through the EU Urban Mobility Observatory, 2025 has seen webinars and pilot reforms of parking and pricing schemes to disincentivize oversized vehicles. On the industry side, Transport & Environment continues releasing 2025 reports tracking how manufacturers adjust their lineups to comply with stricter CO₂ limits for 2025–2027 — indirectly shaping weight and class choices.

How the industry is trying to rein in mass

“Lightweighting” isn’t futuristic — it’s here. Technical articles and reviews from 2025 show paths using advanced alloys, composites, and optimized architecture to balance safety, utility, and mass. While not always tied to specific automakers in public reports, these approaches illustrate where the engineering frontier lies. Automakers are increasingly pushed to thread the needle — maintaining crashworthiness and functionality while trimming unnecessary weight, especially in large segments like SUVs where consumers expect both comfort and scale.

Final thoughts: what to keep in mind & forecast

When you pick a car, don’t fall for the assumption that “heavier = safer for all.” The marginal protective benefit of added mass gets eaten up; beyond that, it can harm other road users. Look instead at independent safety scores (IIHS, Euro NCAP) — especially in collision scenarios involving pedestrians and cyclists. In EVs, consider the full energy picture: weight, route profile, and real-world conditions matter more than the headline range sometimes suggests.

Based on 2025 trends, regulatory and market pressure to optimize weight will only grow — especially for SUVs and large vehicles. Over the next few years, expect stronger adoption of lightweight materials, evolving safety standards, and city-level measures (parking fees, urban access limits) pushing back against the bloat. If the industry finds the right balance, EVs can be powerful, safe, and efficient — without endangering others along the way.